一、Spring cloud stream概述
二、引入包依赖
<dependency> <groupId>org.springframework.kafka</groupId> <artifactId>spring-kafka</artifactId> <version>2.6.4</version> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-stream-kafka</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-stream-binder-kafka</artifactId> </dependency>
三、自定义信息通道
@Input注解标识一个输入通道
@Output注解标识一个输出通道
通道名称作为参数,如果未提供参数,默认使用方法名称作为通道名称。
如下我们自定义信息通道ExamFinishChannel
public interface ExamFinishChannel { String EXAM_FINISH_OUTPUT = "exam-finish-output"; String EXAM_FINISH_INPUT = "exam-finish-input"; @Output(EXAM_FINISH_OUTPUT) MessageChannel sendExamFinishEvent(); @Input(EXAM_FINISH_INPUT) SubscribableChannel receiveExamFinishEvent(); }
四、SpringCloudStream及kafka配置
spring: cloud: stream: kafka: binder: brokers: ${kafka.brokers:127.0.0.1:9092} bindings: exam-finish-output: destination: ${kafka.exam-finish-event:spacer_tiangong_exam_finish_event_dev} content-type: application/json exam-finish-input: destination: ${kafka.exam-finish-event:spacer_tiangong_exam_finish_event_dev} content-type: application/json group: ${kafka.exam-finish-consumer-group:spacer_tiangong_exam_group}
1、定义了通道名称及分组,binder代表绑定实现的标识名称(如kafka或者rabbit),与3中的定义名称相对应。
2、定义了入站消费者的并发性,指在一个实例内的并发性,不同实例之间本身就是并发的,默认值为1
spring.cloud.stream.bindings.<channelName>.consumer.concurrency=1
3、定义了kafka连接信息
如果未配置autoCommitOffset,默认自动提交偏移量
五、发送消息到输出通道
@Slf4j @EnableBinding(ExamFinishChannel.class) public class ExamFinishProducer { @Autowired private ExamFinishChannel examFinishChannel; public void sendExamFinishEventMsg(ExamFinishEventMessage payload) { examFinishChannel.sendExamFinishEvent().send(MessageBuilder.withPayload(payload).build()); log.info("send msg success: {}", payload); } }
六、从输入通道订阅消息
@Slf4j @EnableBinding(ExamFinishChannel.class) public class ExamFinishConsumer { @StreamListener(ExamFinishChannel.EXAM_FINISH_INPUT) public void receive(ExamFinishEventMessage payload) { log.info("start...."); System.out.println(payload); try { Thread.sleep(1000*10); } catch (InterruptedException e) { e.printStackTrace(); } log.info("receive success end:{}", payload); } }
七、这样完整的消息系统就搭建好了,定义Controller发送消息测试
@Autowired private ExamFinishProducer examFinishProducer; @GetMapping("/test") public void test() { ExamFinishEventMessage examFinishEventMessage = new ExamFinishEventMessage(); examFinishEventMessage.setName("mzq"); examFinishProducer.sendExamFinishEventMsg(examFinishEventMessage); examFinishProducer.sendExamFinishEventMsg(examFinishEventMessage); examFinishProducer.sendExamFinishEventMsg(examFinishEventMessage); examFinishProducer.sendExamFinishEventMsg(examFinishEventMessage); }
八、并发性测试
start.... ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq) start.... ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq) start.... ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq) start.... ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq)
如果将concurrency修改为2,即spring.cloud.stream.bindings.exam-finish-input.consumer.concurrency=2
start... start... ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq) ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq) start... ExamFinishEventMessage(name=mzq) start... ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq) receive success end:ExamFinishEventMessage(name=mzq)
从日志可以看出,实现了两个线程的并发消费。