Configuring a Step

  • reader: 提供要处理的项的项目读取器。

  • writer: 处理项目读取器提供的项的项目写入器。

尽管必需依赖项列表较短，但 Step 类是一个复杂的类，可能包含许多协作者，例如：

  • transactionManager: 开始和提交处理期间事务的事务管理器。

  • repository: 定期存储 StepExecution 和 ExecutionContext 的存储库。

  • chunk: 在提交事务之前要处理的项数。

尽管 Step 的必需依赖项列表相对较短，但它是一个可能包含许多协作者的极其复杂的类。

Despite the relatively short list of required dependencies for a Step, it is an extremely complex class that can potentially contain many collaborators.

Java

在使用 Java 配置时，您可以使用 Spring Batch 构建器，如下例所示：

When using Java configuration, you can use the Spring Batch builders, as the following example shows:

Java Configuration
/**
 * Note the JobRepository is typically autowired in and not needed to be explicitly
 * configured
 */
@Bean
public Job sampleJob(JobRepository jobRepository, Step sampleStep) {
    return new JobBuilder("sampleJob", jobRepository)
                .start(sampleStep)
                .build();
}

/**
 * Note the TransactionManager is typically autowired in and not needed to be explicitly
 * configured
 */
@Bean
public Step sampleStep(JobRepository jobRepository, (2)
		PlatformTransactionManager transactionManager) { (1)
	return new StepBuilder("sampleStep", jobRepository)
				.<String, String>chunk(10, transactionManager) (3)
				.reader(itemReader())
				.writer(itemWriter())
				.build();
}
1 transactionManager: Spring 的 PlatformTransactionManager 在处理期间开始并提交事务。
2 transactionManager: Spring’s PlatformTransactionManager that begins and commits transactions during processing.
3 repository: JobRepository 的 Java 特定名称，用于定期存储 StepExecution 和 ExecutionContext 处理期间（在提交之前）。
4 repository: The Java-specific name of the JobRepository that periodically stores the StepExecution and ExecutionContext during processing (just before committing).
5 chunk: 该依赖项的 Java 特定名称，表明这是一个基于项目的步骤以及在提交事务之前要处理的项目数。
6 chunk: The Java-specific name of the dependency that indicates that this is an item-based step and the number of items to be processed before the transaction is committed.

请注意，repository 默认为 jobRepository（通过 @EnableBatchProcessing 提供），transactionManager 默认为 transactionManager（从应用程序上下文中提供）。此外，ItemProcessor 是可选的，因为可以将项目可以直接从读取器传递到写入器。

Note that repository defaults to jobRepository (provided through @EnableBatchProcessing) and transactionManager defaults to transactionManager (provided from the application context). Also, the ItemProcessor is optional, since the item could be directly passed from the reader to the writer.

XML

为了简化配置，您可以使用 Spring Batch XML 命名空间，如下例所示：

To ease configuration, you can use the Spring Batch XML namespace, as the following example shows:

XML Configuration
<job id="sampleJob" job-repository="jobRepository"> (2)
    <step id="step1">
        <tasklet transaction-manager="transactionManager"> (1)
            <chunk reader="itemReader" writer="itemWriter" commit-interval="10"/> (3)
        </tasklet>
    </step>
</job>
1 transaction-manager: Spring 的 PlatformTransactionManager 在处理过程中开始并提交事务。
2 transaction-manager: Spring’s PlatformTransactionManager that begins and commits transactions during processing.
3 job-repository: JobRepository 的 XML 特定名称，用于定期存储 StepExecution 和 ExecutionContext 处理期间（在提交之前）。对于内联 <step/>（在 <job/> 中定义的一个），它是一个 <job/> 元素上的属性。对于独立的 <step/>，它被定义为 <tasklet/> 的属性。
4 job-repository: The XML-specific name of the JobRepository that periodically stores the StepExecution and ExecutionContext during processing (just before committing). For an in-line <step/> (one defined within a <job/>), it is an attribute on the <job/> element. For a standalone <step/>, it is defined as an attribute of the <tasklet/>.
5 commit-interval: 在提交事务之前要处理的项目数的 XML 特定名称。
6 commit-interval: The XML-specific name of the number of items to be processed before the transaction is committed.

请注意，job-repository 默认为 jobRepository，transaction-manager 默认为 transactionManager。此外，ItemProcessor 是可选的，因为可以将该项直接从读者直接传递给写作者。

Note that job-repository defaults to jobRepository and transaction-manager defaults to transactionManager. Also, the ItemProcessor is optional, since the item could be directly passed from the reader to the writer.

前述配置包括创建面向项目的步骤所需的唯一必需依赖项：

The preceding configuration includes the only required dependencies to create a item-oriented step:

  • reader: 为处理提供项目的 ItemReader。

  • reader: The ItemReader that provides items for processing.

  • writer: 处理由 ItemReader 提供的项目的 ItemWriter。

  • writer: The ItemWriter that processes the items provided by the ItemReader.