Spring Cloud Stream
Spring Cloud Stream
事件驱动架构（EDA）是一种软件架构范例。事件生产者和事件消费者是 EDA 的两个主要组成部分。生产者的责任是感知任何状态变化并将该状态呈现为事件消息。生产者不知道谁是该事件的消费者以及该事件的结果是什么。事件的传输将通过事件通道进行。
EDA 模型有两种类型：
- Pub/Sub模型：在该模型中，当事件发生或产生时，系统会将该事件作为消息放入事件流中，监听该流的订阅者将消费该事件。
- 事件流：在此模型中，事件写入日志中，事件使用者不订阅事件流。它可以随时从流的任何部分读取事件。
Spring Cloud Stream 是 Spring 库，它帮助开发人员专注于核心应用程序而不是样板连接器代码。它将许多流行的消息传递平台统一到一个易于使用的 API 背后，包括 RabbitMQ、Apache Kafka、Amazon Kinesis、Google PubSub、Solace PubSub+、Azure 事件中心和 Apache RocketMQ。Spring Cloud Stream支持WebFlux、Multi IO（多个输入和输出）、Multi Binder（您可以在单个应用程序中分别使用Kafka和RabbitMQ作为输入和输出通道）、Kafka Stream功能（例如KTable和KStream等）。
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-stream-kafka</artifactId>
</dependency>
package com.cloud.data.stream;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.function.context.config.ContextFunctionCatalogAutoConfiguration;
@SpringBootApplication(exclude=ContextFunctionCatalogAutoConfiguration.class)
public class EventStreamApplication {
public static void main(String[] args) {
SpringApplication.run(EventStreamApplication.class);
}
}
package com.cloud.data.stream;
import org.springframework.cloud.stream.annotation.Input;
import org.springframework.cloud.stream.annotation.Output;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.SubscribableChannel;
public interface EventStream {
String INBOUND = "event-consumer";
String OUTBOUND = "event-producer";
@Input(INBOUND)
SubscribableChannel consumer();
@Output(OUTBOUND)
MessageChannel producer();
}
package com.cloud.data.stream;
import org.springframework.cloud.stream.annotation.EnableBinding;
@EnableBinding(EventStream.class)
public class EventStreamConfig {
}
spring:
cloud:
stream:
kafka:
binder:
brokers: localhost:9092
bindings:
event-consumer:
destination: data_stream
contentType: application/json
event-producer:
destination: data_stream
contentType: application/json
package com.cloud.data.stream;
public class Message {
private Integer id;
private String name;
private String data;
private byte[] bytePayload;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getData() {
return data;
}
public void setData(String data) {
this.data = data;
}
public byte[] getBytePayload() {
return bytePayload;
}
public void setBytePayload(byte[] bytePayload) {
this.bytePayload = bytePayload;
}
}
package com.cloud.data.stream;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/api/event")
public class EventController {
@Autowired
private EventStreamService eventStreamService;
@PostMapping("/produce")
public Boolean sendEvent(@RequestBody Message msg) throws Exception {
return eventStreamService.produceEvent(msg);
}
}
package com.cloud.data.stream;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.integration.support.MessageBuilder;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHeaders;
import org.springframework.stereotype.Service;
import org.springframework.util.MimeTypeUtils;
@Service
public class EventStreamService {
@Autowired
private EventStream eventStream;
public Boolean produceEvent(Message msg) {
System.out.println("Producing events --> id: "+ msg.getId() +" name: "+msg.getName()+" Actual message: "+ msg.getData());
msg.setBytePayload(msg.getData().getBytes());
MessageChannel messageChannel = eventStream.producer();
return messageChannel.send(MessageBuilder.withPayload(msg)
.setHeader(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_JSON).build());
}
}
package com.cloud.data.stream;
import org.springframework.cloud.stream.annotation.StreamListener;
import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.handler.annotation.Payload;
@Configuration
public class EventConsumer {
@StreamListener(EventStream.INBOUND)
public void consumeEvent(@Payload Message msg) {
System.out.println("Inbound message--> id: " + msg.getId() + " name: " + msg.getName() + " Actual message: "
+ msg.getData() + " bytePayload: " + msg.getBytePayload());
}
}
