我们正在尝试从 jdbc 源进行轮询,聚合消息,然后将聚合器的输出发送到 kafka 流和 jdbcMessageHandler (以更新我们轮询的行,以便它们不再被轮询。实际上是单独的表格)。我们正在使用 IntegrationFlow DSL。轮询和聚合工作正常。多个输出/源/通道/处理程序的输出不起作用。
我们当前的流程如下所示:
IntegrationFlowBuilder flowBuilder = IntegrationFlows.from(jdbcMessageSource(), new Consumer<SourcePollingChannelAdapterSpec>(){
@Override
public void accept(SourcePollingChannelAdapterSpec sourcePollingChannelAdapterSpec) {
sourcePollingChannelAdapterSpec.poller(poller);
}
})
.split()
.transform((message)-> {
// do our stuff; output is a simple POJO representing a single row from the db
})
.aggregate(aggregator -> aggregator) // details spared but it works fine; output is a larger POJO containing a collection of the row objects
.channel(this.source.output()) // this goes to kafka
.handle(jdbcMessageHandler()); // doesn't get here
这是我们的投票来源:
@Bean
public MessageSource<Object> jdbcMessageSource() {
JdbcPollingChannelAdapter jdbcPollingChannelAdapter = new JdbcPollingChannelAdapter(this.dataSource, this.properties.getQuery());
jdbcPollingChannelAdapter.setSelectSqlParameterSource(createSqlParameterSource());
return jdbcPollingChannelAdapter;
}
jdbcMessageHandler 就是这样:
@Bean
public MessageHandler jdbcMessageHandler() {
return new JdbcMessageHandler(dataSource, this.properties.getUpdate());
}
this.output 就是这样:
@Autowired
private Source source;
它通过 @EnableBinding(Source.class) 映射到我们的 application.yml 中的 kafka 主题:
spring:
cloud:
stream:
bindings:
output: our.topic
我们的大部分属性都定义在 application.yml 文件中,我们使用这些属性和注释而不是 XMl 配置。
有了上面的内容,它可以很好地写入 kafka,但没有到达 jdbcMessageHandler。
我这样做的时候工作过(在聚合器之后):
.publishSubscribeChannel(publishSubscribeSpec -> publishSubscribeSpec
.subscribe(flow -> flow
.handle(jdbcMessageHandler()))
)
.channel(this.source.output())
但这是错误的顺序;我们要确保首先将消息写入 kafka,然后更新跟踪已成功轮询哪些行的表。
jdbcMessageHandler 简单地包装了一个使用来自消息的值的 INSERT 语句,所以我假设有多种方法可以做到这一点。jdbcOutboundGateway 是一种方式吗?看起来这是为了进行另一个查询并返回一个结果以进行进一步处理,这不适合我们的用例。
还建议使用轮询来更新,因为我们使用轮询作为我们的来源。我调查了这个。我认为这也行不通,因为它似乎在轮询后立即进行更新,甚至在轮询结果被处理之前,所以在最终聚合消息发送到 kafka 之前进行更新的时间也有同样的问题.
编辑:我尝试了下面的答案,所以当前流程是这样的:
@Bean
public IntegrationFlow pollingFlow() {
IntegrationFlowBuilder flowBuilder = IntegrationFlows.from(jdbcMessageSource(), new Consumer<SourcePollingChannelAdapterSpec>(){
@Override
public void accept(SourcePollingChannelAdapterSpec sourcePollingChannelAdapterSpec) {
sourcePollingChannelAdapterSpec.poller(poller);
}
})
.split()
.transform((message)-> {
// transform ResultSet; output is a simple POJO representing a single row from the db
})
.aggregate(aggregator -> aggregator) // details spared but it works fine; output is a larger POJO containing a collection of the row objects
.publishSubscribeChannel(publishSubscribeSpec -> publishSubscribeSpec
.subscribe(flow -> flow
.handle(this.source.output()))
.subscribe(flow -> flow
.handle(jdbcMessageHandler()))
);
}
并在启动时收到以下错误:
java.lang.IllegalArgumentException: Found ambiguous parameter type [interface org.springframework.messaging.MessageHandler] for method match: [public boolean org.springframework.integration.channel.AbstractSubscribableChannel.unsubscribe(org.springframework.messaging.MessageHandler), public void org.springframework.integration.channel.AbstractMessageChannel.configureMetrics(org.springframework.integration.support.management.AbstractMessageChannelMetrics), public void org.springframework.integration.channel.AbstractMessageChannel.setDatatypes(java.lang.Class[]), public org.springframework.messaging.support.ChannelInterceptor org.springframework.integration.channel.AbstractMessageChannel.removeInterceptor(int), public void org.springframework.integration.context.IntegrationObjectSupport.setApplicationContext(org.springframework.context.ApplicationContext) throws org.springframework.beans.BeansException, public boolean org.springframework.integration.channel.AbstractMessageChannel.removeInterceptor(org.springframework.messaging.support.ChannelInterceptor), public java.lang.String org.springframework.integration.context.IntegrationObjectSupport.getComponentName(), public void org.springframework.integration.channel.AbstractMessageChannel.setStatsEnabled(boolean), public void org.springframework.integration.channel.AbstractMessageChannel.setMessageConverter(org.springframework.messaging.converter.MessageConverter), public void org.springframework.integration.context.IntegrationObjectSupport.setMessageBuilderFactory(org.springframework.integration.support.MessageBuilderFactory), public void org.springframework.integration.context.IntegrationObjectSupport.setBeanFactory(org.springframework.beans.factory.BeanFactory), public void org.springframework.integration.context.IntegrationObjectSupport.setComponentName(java.lang.String), public void org.springframework.integration.channel.AbstractMessageChannel.setInterceptors(java.util.List), public final void org.springframework.integration.context.IntegrationObjectSupport.setPrimaryExpression(org.springframework.expression.Expression), public void org.springframework.integration.context.IntegrationObjectSupport.setChannelResolver(org.springframework.messaging.core.DestinationResolver)]
at org.springframework.util.Assert.isNull(Assert.java:113)
at org.springframework.integration.util.MessagingMethodInvokerHelper.findHandlerMethodsForTarget(MessagingMethodInvokerHelper.java:499)
at org.springframework.integration.util.MessagingMethodInvokerHelper.<init>(MessagingMethodInvokerHelper.java:226)
at org.springframework.integration.util.MessagingMethodInvokerHelper.<init>(MessagingMethodInvokerHelper.java:149)
at org.springframework.integration.util.MessagingMethodInvokerHelper.<init>(MessagingMethodInvokerHelper.java:144)
at org.springframework.integration.handler.MethodInvokingMessageProcessor.<init>(MethodInvokingMessageProcessor.java:60)
at org.springframework.integration.handler.ServiceActivatingHandler.<init>(ServiceActivatingHandler.java:37)
at org.springframework.integration.dsl.IntegrationFlowDefinition.handle(IntegrationFlowDefinition.java:985)
at org.springframework.integration.dsl.IntegrationFlowDefinition.handle(IntegrationFlowDefinition.java:964)
at org.springframework.integration.dsl.IntegrationFlowDefinition.handle(IntegrationFlowDefinition.java:950)
我调试并进入了 IntegrationFlowDefinition 上的 .handle() 方法,发现传递的对象以某种方式转换为 DirectChannel,我不明白。