File Aggregator

从版本 5.5 开始，引入了“FileAggregator”来涵盖在启用 START/END 标记时“FileSplitter”使用案例的另一面。为了方便，“FileAggregator”实现了所有三个序列详细信息策略：

Starting with version 5.5, a FileAggregator is introduced to cover other side of FileSplitter use-case when START/END markers are enabled. For convenience the FileAggregator implements all three sequence details strategies:

  • 具有 `FileHeaders.FILENAME`属性的 `HeaderAttributeCorrelationStrategy`用于关联键计算。当在 `FileSplitter`上启用标记时，它不会填充序列详情标头，因为开始/结束标记消息也包含在序列大小中。`FileHeaders.FILENAME`仍会为发出的每一行（包括开始/结束标记消息）填充。

  • The HeaderAttributeCorrelationStrategy with the FileHeaders.FILENAME attribute is used for correlation key calculation. When markers are enabled on the FileSplitter, it does not populate sequence details headers, since START/END marker messages are also included into the sequence size. The FileHeaders.FILENAME is still populated for each line emitted, including START/END marker messages.

  • FileMarkerReleaseStrategy - 检查组中的 FileSplitter.FileMarker.Mark.END`消息，然后将 `FileHeaders.LINE_COUNT`标头值与组大小减去 `2 - `FileSplitter.FileMarker`实例进行比较。它还实现在 `GroupConditionProvider`中使用的 `AbstractCorrelatingMessageHandler`的一个便利 `conditionSupplier`联系人。有关更多信息，请参见 Message Group Condition。

  • The FileMarkerReleaseStrategy - checks for FileSplitter.FileMarker.Mark.END message in the group and then compare a FileHeaders.LINE_COUNT header value with the group size minus 2 - FileSplitter.FileMarker instances. It also implements a convenient GroupConditionProvider contact for conditionSupplier function to be used in the AbstractCorrelatingMessageHandler. See Message Group Condition for more information.

  • `FileAggregatingMessageGroupProcessor`只从组中移除 `FileSplitter.FileMarker`消息并收集其余消息到列表有效负载中以进行产生。

  • The FileAggregatingMessageGroupProcessor just removes FileSplitter.FileMarker messages from the group and collect the rest of messages into a list payload to produce.

以下清单展示了配置“FileAggregator”的可能方法：

The following listing shows possible ways to configure a FileAggregator:

  • Java DSL

  • Kotlin DSL

  • Java

  • XML

@Bean
public IntegrationFlow fileSplitterAggregatorFlow(TaskExecutor taskExecutor) {
    return f -> f
            .split(Files.splitter()
                    .markers()
                    .firstLineAsHeader("firstLine"))
            .channel(c -> c.executor(taskExecutor))
            .filter(payload -> !(payload instanceof FileSplitter.FileMarker),
                    e -> e.discardChannel("aggregatorChannel"))
            .<String, String>transform(String::toUpperCase)
            .channel("aggregatorChannel")
            .aggregate(new FileAggregator())
            .channel(c -> c.queue("resultChannel"));
}
@Bean
fun fileSplitterAggregatorFlow(taskExecutor: TaskExecutor?) =
    integrationFlow {
        split(Files.splitter().markers().firstLineAsHeader("firstLine"))
        channel { executor(taskExecutor) }
        filter<Any>({ it !is FileMarker }) { discardChannel("aggregatorChannel") }
        transform(String::toUpperCase)
        channel("aggregatorChannel")
        aggregate(FileAggregator())
        channel { queue("resultChannel") }
    }
@serviceActivator(inputChannel="toAggregateFile")
@Bean
public AggregatorFactoryBean fileAggregator() {
    AggregatorFactoryBean aggregator = new AggregatorFactoryBean();
    aggregator.setProcessorBean(new FileAggregator());
    aggregator.setOutputChannel(outputChannel);
    return aggregator;
}
<int:chain input-channel="input" output-channel="output">
    <int-file:splitter markers="true"/>
    <int:aggregator>
        <bean class="org.springframework.integration.file.aggregator.FileAggregator"/>
    </int:aggregator>
</int:chain>

如果“FileAggregator”的默认行为不能满足目标逻辑，建议使用各个策略配置聚合器端点。有关详细信息，请参阅“FileAggregator”JavaDocs。

If default behavior of the FileAggregator does not satisfy the target logic, it is recommended to configure an aggregator endpoint with individual strategies. See FileAggregator JavaDocs for more information.