Spring Cloud Stream 初尝

Posted by shellj on
公司里目前用的是RocketMQ,用的过程中遇到一些问题,逐渐将一些业务转到 kafka 上,正好目前项目是spring boot项目,所以就来试试 spring cloud stream,本地环境有 rabbitmq,所以使用它了。
依赖
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-stream-binder-rabbit</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-stream-test-support</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>
定义接收器
public interface MyReceiver {
    @Input("my-channel")
    SubscribableChannel input();
}
定义发送器
public interface MySender {
    @Output("my-channle")
    MessageChannel output();
}
上面的 @Input()@Output() 里的参数就是绑定的名字,需要使用一致的名字。
接受发送消息
@EnableBinding(value = {MyReceiver.class, MySender.class})
@RestController
@Slf4j
public class MessageController {

     @Autowired
    private MySender sender;
    
    /**
     * 发送
     */
    @PostMapping("/send")
    public void send(@RequestParam("message") String message) {
        sender.output().send(MessageBuilder.withPayload(message).build());
    }

     /**
     * 接收
     */
    @StreamListener("my-channel")
    public void receive(String message) {
        log.info("Received: {}", message);
    }
}
必须加上 @EnableBinding(value = {MyReceiver.class}),使接收生效,在接收方法上加上 @StreamListener("my-channel")
和接收一样,需要加上 @EnableBinding(value = {MySender.class}) 使发送生效(应该是创建代理类吧)。
但上面接收和发送在一个项目里面启动的时候会失败,spring会把 @Input@Output 绑定的名字作为Bean的名字创建Bean,所以就重复了,解决方法是在代码里设置成不同的名字,然后在配置文件里指定 destination
spring:
  cloud:
    stream:
      bindings:
        input:
          destination: my-channel
        output:
          destination: my-channel
最终的代码是
public interface MyReceiver {
    @Input(Sink.INPUT)
    SubscribableChannel input();
}
public interface MySender {
    @Output(Source.OUTPUT)
    MessageChannel output();
}
@EnableBinding(value = {MyReceiver.class, MySender.class})
@RestController
@Slf4j
public class MessageController {

    @Autowired
    private MySender sender;

    @PostMapping("/send")
    public void send(@RequestParam("message") String message) {
        sender.output().send(MessageBuilder.withPayload(message).build());
    }

    @StreamListener(Sink.INPUT)
    public void receive(String message) {
        log.info("Received: {}", message);
    }
}
调用接口可以看到控制台的打印
curl -XPOST 'localhost:8080/send?message=hello-world'