SpringCloudStream事件驱动2步骤-RabbitMQ

Spring Cloud Stream 事件驱动 2步骤

注解/接口了解

Spring Cloud Stream 内置了三个Source、Sink、Processor接口

• Source 发送消息接口 内含@Output(“output”)
• Sink 消息的消费者接口 内含@Input(“input”)
• Processor 继承了Source,Sink

@Output(“output”) 标志为一个输出流，会加入到Spring IOC管理

@Input(“input”) 标志为一个输入流，会加入到Spring IOC管理

@EnableBinding({Source.class,Sink,class}) 开启输入流和输出流的代理绑定

@StreamListener(Sink.INPUT) 监听输入流

@ServiceActivator(inputChannel = Sink.INPUT) 监听输入流，优先级比@StreamListener低

<dependency>
    <groupId>org.springframework.cloudgroupId>
    <artifactId>spring-cloud-starter-stream-rabbitartifactId>
dependency>

一、java实现（任何一种即可）

1、默认实现

• 发布消息实现，发布到Source.OUTPUT的输出流（此是内置的输出接口）

  package com.ksaas.cloud.service.system.infrastructure.event.default2;
  
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.cloud.stream.messaging.Source;
  import org.springframework.messaging.MessageChannel;
  import org.springframework.messaging.support.MessageBuilder;
  import org.springframework.stereotype.Component;
  
  import javax.annotation.Resource;
  
  /**
   * @author kylin
   * @desc 内置的发送代码demo
   */
  @Component
  public class SourcePublisher {
  
      @Resource
      @Qualifier(Source.OUTPUT)
      MessageChannel messageChannel;
  
      public void test(String message) {
          messageChannel.send(MessageBuilder.withPayload(message).build());
          System.out.println("test default source");
      }
  }
  
  

• 接受消息实现，接受到Sink.INPUT的输入流（此是内置的输如入接口）

  package com.ksaas.cloud.service.system.infrastructure.event.default2;
  
  import org.springframework.cloud.stream.annotation.StreamListener;
  import org.springframework.cloud.stream.messaging.Sink;
  import org.springframework.messaging.Message;
  import org.springframework.stereotype.Component;
  
  /**
   * @author kylin
   * 内置的接受端代码demo
   */
  @Component
  public class SinkReceiver {
  
      // 第一种实现，优先级最高
      @StreamListener(Sink.INPUT)
      public void test(Message message) {
          System.out.println("test default sink: " + message);
      }
  
  //	 // 第二种实现，优先级低于@StreamListener
  //    @ServiceActivator(inputChannel = Sink.INPUT)
  //    public void test(Message message) {
  //        System.out.println("test default sink: " + message);
  //    }
  
  //	 // 第三种，优先级最低，采用的@PostConstruct+SubscribableChannel实现
  //    @Resource
  //    @Qualifier(Sink.INPUT)
  //    SubscribableChannel subscribableChannel;
  //    @PostConstruct
  //    public void test() {
  //        subscribableChannel.subscribe(message -> {
  //            System.out.println("test default sink: " + message);
  //        });
  //    }
  }
  
  

• 启动代理绑定

  package com.ksaas.cloud.service.system.infrastructure.event.default2;
  
  import org.springframework.cloud.stream.annotation.EnableBinding;
  import org.springframework.cloud.stream.messaging.Sink;
  import org.springframework.cloud.stream.messaging.Source;
  
  /**
   * @author kylin
   */
  @EnableBinding({Source.class, Sink.class})
  public class DefaultSpringCloudStreamConfig {
  }
  
  

2、自定义实现

• 创建CustomSource接口(名字自定义)：输出流

  package com.ksaas.cloud.service.system.infrastructure.event.custom;
  
  import org.springframework.cloud.stream.annotation.Output;
  import org.springframework.messaging.MessageChannel;
  
  /**
   * 自定义发送端需申明接口，（同Source一样，只是名字区分）
   *
   * @author kylin
   */
  public interface CustomSource {
      String TEST_OUT_PUT = "customOutput";
  
      @Output(TEST_OUT_PUT)
      MessageChannel testOutput();
  }
  
  

• 创建CustomSink接口(名字自定义)：输入流

  package com.ksaas.cloud.service.system.infrastructure.event.custom;
  
  import org.springframework.cloud.stream.annotation.Input;
  import org.springframework.messaging.MessageChannel;
  
  /**
   * 自定义接受端需申明接口，（同Sink一样，只是名字区分）
   *
   * @author kylin
   */
  public interface CustomSink {
      String TEST_IN_PUT = "customInput";
  
      @Input(TEST_IN_PUT)
      MessageChannel testOutput();
  }
  
  

• 发布消息实现，发布到CustomSource.TEST_OUT_PUT的输出流（其实和默认的操作含义一样）

  package com.ksaas.cloud.service.system.infrastructure.event.custom;
  
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.messaging.MessageChannel;
  import org.springframework.messaging.support.MessageBuilder;
  import org.springframework.stereotype.Component;
  
  import javax.annotation.Resource;
  
  /**
   * 自定义的发送端代码demo
   *
   * @author kylin
   */
  
  @Component
  public class CustomSourcePublisher {
  
      @Resource
      @Qualifier(CustomSource.TEST_OUT_PUT)
      MessageChannel messageChannel;
  
      public void test(String message) {
          messageChannel.send(MessageBuilder.withPayload(message).build());
          System.out.println("test custom source");
      }
  }
  
  

• 接受消息实现，接受到CustomSink.TEST_IN_PUT的输入流（其实和默认的操作含义一样）

  package com.ksaas.cloud.service.system.infrastructure.event.custom;
  
  import org.springframework.cloud.stream.annotation.StreamListener;
  import org.springframework.messaging.Message;
  import org.springframework.stereotype.Component;
  
  /**
   * 自定义的接受端代码demo
   *
   * @author kylin
   */
  @Component
  public class CustomSinkReceiver {
  
      @StreamListener(CustomSink.TEST_IN_PUT)
      public void test(Message message) {
          System.out.println();
          System.out.println("test custom sink: " + message);
      }
  }
  // .... 
  

• 启动自定义代理绑定（其实和默认的操作含义一样）

  package com.ksaas.cloud.service.system.infrastructure.event.custom;
  
  import org.springframework.cloud.stream.annotation.EnableBinding;
  
  /**
   * @author kylin
   */
  @EnableBinding({CustomSource.class, CustomSink.class})
  public class CustomSpringCloudStreamConfig {
  }
  
  

二、配置输出流/输入流绑定

配置发送端和消费端的绑定

spring:
  cloud:
    stream:
      bindings:
      	# 默认的发送端 destination 代表绑定到的名称
      	#（不管是默认还是自定义都需要这样关联，除非发送/接口都是一个名称）
        output:
          destination: kylin_default
          content-type: application/json
        # 默认的接受 destination 代表绑定到的名称
        input:
          destination: kylin_default
          content-type: application/json
          group: group-cus1
        
        
        # 自定义：说明customOutput 和customInput 绑定到了 kylin_custom
        customOutput:
          destination: kylin_custom
          content-type: application/json
        customInput:
          destination: kylin_custom
          content-type: application/json
          group: group-cus1