CQL Template API
CqlTemplate 类（及其反应式变体 ReactiveCqlTemplate）是核心 CQL 包中的核心类。它处理资源的创建和释放。它执行核心 CQL 工作流的基本任务，例如语句创建和执行，并留待应用程序代码提供 CQL 并提取结果。 CqlTemplate 类执行 CQL 查询和更新语句，对 ResultSet 实例进行迭代，并提取返回的参数值。它还会捕获 CQL 异常，并将它们转换为在 org.springframework.dao 包中定义的通用、更多的信息性异常层次结构。
The CqlTemplate class (and its reactive variant ReactiveCqlTemplate) is the central class in the core CQL package.
It handles the creation and release of resources.
It performs the basic tasks of the core CQL workflow, such as statement creation and execution, and leaves application code to provide CQL and extract results.
The CqlTemplate class executes CQL queries and update statements, performs iteration over ResultSet instances and extraction of returned parameter values.
It also catches CQL exceptions and translates them to the generic, more informative, exception hierarchy defined in the org.springframework.dao package.
当您将 CqlTemplate`用于您的代码时，您只需实现具有明确定义的契约的回调接口。给定 `Connection，`PreparedStatementCreator`回调接口将使用提供的 CQL 和任何必需的参数创建一个 prepared statement。`RowCallbackHandler`接口从 `ResultSet`的每一行中提取值。
When you use the CqlTemplate for your code, you need only implement callback interfaces, which have a clearly defined contract.
Given a Connection, the PreparedStatementCreator callback interface creates a prepared statement with the provided CQL and any necessary parameter arguments.
The RowCallbackHandler interface extracts values from each row of a ResultSet.
CqlTemplate 可在 DAO 实现中直接通过包含 SessionFactory 引用的实例化使用，或者在 Spring 容器中进行配置并作为 Bean 引用提供给 DAO。CqlTemplate 是 CassandraTemplate 的基础构建块。
The CqlTemplate can be used within a DAO implementation through direct instantiation with a SessionFactory reference or be configured in the Spring container and given to DAOs as a bean reference. CqlTemplate is a foundational building block for CassandraTemplate.
此类发出的所有 CQL 都在与模板实例的全限定类名（通常为 CqlTemplate，但如果您使用 CqlTemplate 类的自定义子类，可能有所不同）对应的类目下以 DEBUG 级别记录。
All CQL issued by this class is logged at the DEBUG level under the category corresponding to the fully-qualified class name of the template instance (typically CqlTemplate, but it may be different if you use a custom subclass of the CqlTemplate class).
您可以通过配置 CQL API 实例（CqlTemplate、AsyncCqlTemplate 和 ReactiveCqlTemplate）上的这些参数来控制获取大小、一致性级别和重试策略的默认值。如果没有设置特定查询选项，则应用默认设置。
You can control fetch size, consistency level, and retry policy defaults by configuring these parameters on the CQL API instances: CqlTemplate, AsyncCqlTemplate, and ReactiveCqlTemplate.
Defaults apply if the particular query option is not set.
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Examples of CqlTemplate Class Usage
此部分提供了一些关于 `CqlTemplate`类在实际使用中的示例。这些示例并非 `CqlTemplate`公开的所有功能的详尽列表。有关该内容，请参见 Javadoc。
This section provides some examples of the CqlTemplate class in action.
These examples are not an exhaustive list of all functionality exposed by the CqlTemplate.
See the Javadoc for that.
Querying (SELECT) with CqlTemplate
下面的查询获取表中的行数：
The following query gets the number of rows in a table:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}以下查询使用绑定变量：
The following query uses a bind variable:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}以下示例查询 String：
The following example queries for a String:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}以下示例查询并填充单个域对象：
The following example queries and populates a single domain object:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}以下示例查询并填充多个域对象：
The following example queries and populates multiple domain objects:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}如果最后两个代码片断实际上存在于同一个应用程序中，那么消除两个 RowMapper 匿名内部类中存在的重复并将其提取到一个可以由 DAO 方法引用的单个类（通常是 static 嵌套类）中是有意义的。
If the last two snippets of code actually existed in the same application, it would make sense to remove the duplication present in the two RowMapper anonymous inner classes and extract them out into a single class (typically a static nested class) that can then be referenced by DAO methods.
例如，最好将最后一个代码片断写成如下形式：
For example, it might be better to write the last code snippet as follows:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}INSERT, UPDATE, and DELETE with CqlTemplate
您可以使用 execute(…) 方法执行 INSERT、UPDATE 和 DELETE 操作。参数值通常以可变参数或对象数组的形式提供。
You can use the execute(…) method to perform INSERT, UPDATE, and DELETE operations.
Parameter values are usually provided as variable arguments or, alternatively, as an object array.
以下示例展示如何使用 CqlTemplate 执行 INSERT 操作：
The following example shows how to perform an INSERT operation with CqlTemplate:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}以下示例展示如何使用 CqlTemplate 执行 UPDATE 操作：
The following example shows how to perform an UPDATE operation with CqlTemplate:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}下面的示例演示如何使用 CqlTemplate 执行 DELETE 操作：
The following example shows how to perform an DELETE operation with CqlTemplate:
-
Imperative
-
Reactive
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}/*
* Copyright 2023-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.ReactiveCqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class ReactiveCqlTemplateExamples {
private ReactiveCqlTemplate reactiveCqlTemplate = null;
void examples() {
// tag::rowCount[]
Mono<Integer> rowCount = reactiveCqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
Mono<Integer> countOfActorsNamedJoe = reactiveCqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
Mono<String> lastName = reactiveCqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Mono<Actor> actor = reactiveCqlTemplate.queryForObject(
"SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}},
1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
Flux<Actor> actors = reactiveCqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
Flux<String> lastNames = reactiveCqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
Flux<Actor> findAllActors() {
return reactiveCqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void insert() {
// tag::insert[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
}
@Test
void update() {
// tag::update[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
}
@Test
void delete() {
long actorId = 1;
// tag::delete[]
Mono<Boolean> applied = reactiveCqlTemplate.execute(
"DELETE FROM actor WHERE id = ?",
actorId);
// end::delete[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}Other CqlTemplate operations
你可以使用 execute(..) 方法来执行任何任意的 CQL，结果是，该方法通常用于 DDL 语句，它被大量重载，其中使用了采用回调接口、绑定变量阵列等方法的变体。
You can use the execute(..) method to execute any arbitrary CQL.
As a result, the method is often used for DDL statements.
It is heavily overloaded with variants that take callback interfaces, bind variable arrays, and so on.
下面的示例演示如何使用传递给 execute() 方法的所有不同的 API 对象来创建和删除表：
The following example shows how to create and drop a table by using different API objects that are all passed to the execute() methods:
/*
* Copyright 2020-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https:://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra.example;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.springframework.data.cassandra.core.cql.CqlTemplate;
import org.springframework.data.cassandra.core.cql.RowMapper;
import org.springframework.data.cassandra.core.cql.generator.DropTableCqlGenerator;
import org.springframework.data.cassandra.core.cql.keyspace.DropTableSpecification;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* @author Mark Paluch
*/
//@formatter:off
public class CqlTemplateExamples {
private CqlTemplate cqlTemplate = null;
void examples() {
// tag::rowCount[]
int rowCount = cqlTemplate.queryForObject("SELECT COUNT(*) FROM t_actor", Integer.class);
// end::rowCount[]
// tag::countOfActorsNamedJoe[]
int countOfActorsNamedJoe = cqlTemplate.queryForObject(
"SELECT COUNT(*) FROM t_actor WHERE first_name = ?", Integer.class, "Joe");
// end::countOfActorsNamedJoe[]
// tag::lastName[]
String lastName = cqlTemplate.queryForObject(
"SELECT last_name FROM t_actor WHERE id = ?",
String.class, 1212L);
// end::lastName[]
// tag::rowMapper[]
Actor actor = cqlTemplate.queryForObject("SELECT first_name, last_name FROM t_actor WHERE id = ?",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}, 1212L);
// end::rowMapper[]
// tag::listOfRowMapper[]
List<Actor> actors = cqlTemplate.query(
"SELECT first_name, last_name FROM t_actor",
new RowMapper<Actor>() {
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
});
// end::listOfRowMapper[]
// tag::preparedStatement[]
List<String> lastNames = cqlTemplate.query(
session -> session.prepare("SELECT last_name FROM t_actor WHERE id = ?"),
ps -> ps.bind(1212L),
(row, rowNum) -> row.getString(0));
// end::preparedStatement[]
}
// tag::findAllActors[]
List<Actor> findAllActors() {
return cqlTemplate.query("SELECT first_name, last_name FROM t_actor", ActorMapper.INSTANCE);
}
enum ActorMapper implements RowMapper<Actor> {
INSTANCE;
public Actor mapRow(Row row, int rowNum) {
Actor actor = new Actor();
actor.setFirstName(row.getString("first_name"));
actor.setLastName(row.getString("last_name"));
return actor;
}
}
// end::findAllActors[]
@Test
void prepared() {
long actorId = 1;
// tag::insert[]
cqlTemplate.execute(
"INSERT INTO t_actor (first_name, last_name) VALUES (?, ?)",
"Leonor", "Watling");
// end::insert[]
// tag::update[]
cqlTemplate.execute(
"UPDATE t_actor SET last_name = ? WHERE id = ?",
"Banjo", 5276L);
// end::update[]
// tag::delete[]
cqlTemplate.execute(
"DELETE FROM t_actor WHERE id = ?",
5276L);
// end::delete[]
}
@Test
void other() {
// tag::other[]
cqlTemplate.execute("CREATE TABLE test_table (id uuid primary key, event text)");
DropTableSpecification dropper = DropTableSpecification.dropTable("test_table");
String cql = DropTableCqlGenerator.toCql(dropper);
cqlTemplate.execute(cql);
// end::other[]
}
static class Actor {
void setFirstName(String first_name) {
}
void setLastName(String last_name) {}
}
}Controlling Cassandra Connections
应用程序通过使用 CqlSession 对象连接到 Apache Cassandra，Cassandra CqlSession 跟踪跟单个节点的多个连接，旨在成为一个线程安全的长生存期对象，通常，你可以为整个应用程序使用一个单独的 CqlSession。
Applications connect to Apache Cassandra by using CqlSession objects.
A Cassandra CqlSession keeps track of multiple connections to the individual nodes and is designed to be a thread-safe, long-lived object.
Usually, you can use a single CqlSession for the whole application.
Spring 通过 SessionFactory 获取一个 Cassandra CqlSession，SessionFactory 是 Spring Data for Apache Cassandra 的一部分，它是一个泛化的连接工厂，它让容器或框架对应用程序代码隐藏连接处理和路由问题。
Spring acquires a Cassandra CqlSession through a SessionFactory. SessionFactory is part of Spring Data for Apache Cassandra and is a generalized connection factory.
It lets the container or framework hide connection handling and routing issues from the application code.
下面的示例演示如何配置一个默认的 SessionFactory：
The following example shows how to configure a default SessionFactory:
-
Imperative
-
Reactive
CqlSession session = … // get a Cassandra Session
CqlTemplate template = new CqlTemplate();
template.setSessionFactory(new DefaultSessionFactory(session));CqlSession session = … // get a Cassandra Session
ReactiveCqlTemplate template = new ReactiveCqlTemplate(new DefaultBridgedReactiveSession(session));CqlTemplate 和其他模板 API 实现为每个操作获取一个 CqlSession，由于它们长期存在的性质，在调用所需操作后，会话不会被关闭，正确资源释放的职责在于使用该会话的容器或框架。
CqlTemplate and other Template API implementations obtain a CqlSession for each operation.
Due to their long-lived nature, sessions are not closed after invoking the desired operation.
Responsibility for proper resource disposal lies with the container or framework that uses the session.
你可以在 org.springframework.data.cassandra.core.cql.session 包中找到 diverse SessionFactory 实现。
You can find various SessionFactory implementations within the org.springframework.data.cassandra.core.cql.session
package.
Exception Translation
Spring Framework 为各种不同的数据库和映射技术提供异常转换，这些技术传统上是 JDBC 和 JPA，Spring Data for Apache Cassandra 通过提供 org.springframework.dao.support.PersistenceExceptionTranslator 接口的实现来将这个特性扩展到 Apache Cassandra。
The Spring Framework provides exception translation for a wide variety of database and mapping technologies.
This has traditionally been for JDBC and JPA.
Spring Data for Apache Cassandra extends this feature to Apache Cassandra by providing an implementation of the org.springframework.dao.support.PersistenceExceptionTranslator interface.
映射到 Spring 的 一致的数据访问异常层级 的动机是让您编写可移植且描述性的异常处理代码，而无需诉诸于与特定 Cassandra 异常进行编码和处理。Spring 的所有数据访问异常均继承自 DataAccessException 类，因此，您可确保在单个 try-catch 块内捕获所有与数据库相关异常。
The motivation behind mapping to Spring’s consistent data access exception hierarchy
is to let you write portable and descriptive exception handling code without resorting to coding against and handling specific Cassandra exceptions.
All of Spring’s data access exceptions are inherited from the
DataAccessException class, so you can be sure that you can catch all database-related exceptions within a single try-catch block.
ReactiveCqlTemplate 和 ReactiveCassandraTemplate 尽早传播异常，在处理响应式序列期间发生的异常作为错误信号发出。
ReactiveCqlTemplate and ReactiveCassandraTemplate propagate exceptions as early as possible.
Exceptions that occur during the processing of the reactive sequence are emitted as error signals.