headers exchange是根据消息header值而不是routing key将消息路由到队列的交换器。
生产者在消息头中以键值对的形式添加一些值，并将其发送到headers exchange,
收到消息后，headers exchange尝试将所有或任何（基于x-match的值）header值与绑定到它的所有队列的值匹配。 如果找到匹配，则将消息路由到绑定值匹配的队列，如果未找到匹配，则忽略该消息
1. 完整示例代码
编写HeaderExchangeConfig.java配置文件，已声明headers exchange及其绑定
@Configuration
public class HeaderExchangeConfig {
@Bean
public HeadersExchange headers() {
return new HeadersExchange("headers");
}
private static class ConsumerConfig {
@Bean
public Queue headersAutoDeleteQueue1() {
return new AnonymousQueue();
}
@Bean
public Queue headersAutoDeleteQueue2() {
return new AnonymousQueue();
}
@Bean
public Queue headersAutoDeleteQueue3() {
return new AnonymousQueue();
}
@Bean
public Binding headersBinding1(HeadersExchange headers, Queue headersAutoDeleteQueue1) {
Map<String, Object> headerMap = new HashMap<>();
headerMap.put("h1", "Header1");
headerMap.put("h2", "Header2");
/**
* 匹配到任意一个就发送至队列
*/
return BindingBuilder.bind(headersAutoDeleteQueue1).to(headers).whereAny(headerMap).match();
}
@Bean
public Binding headersBinding2(HeadersExchange headers, Queue headersAutoDeleteQueue2) {
Map<String, Object> headerMap = new HashMap<>();
headerMap.put("h1", "Header1");
headerMap.put("h2", "Header2");
/**
* 全部匹配到才会发送至队列
*/
return BindingBuilder.bind(headersAutoDeleteQueue2).to(headers).whereAll(headerMap).match();
}
@Bean
public Binding headersBinding3(HeadersExchange headers, Queue headersAutoDeleteQueue3) {
/**
* 匹配到任意一个就发送至队列， 此处与headersBinding1一致，为了证明其也有fanout模式的功能
*/
Map<String, Object> headerMap = new HashMap<>();
headerMap.put("h1", "Header1");
headerMap.put("h2", "Header2");
return BindingBuilder.bind(headersAutoDeleteQueue3).to(headers).whereAny(headerMap).match();
}
}
}
编写生产者
@Component
public class HeaderSender {
private RabbitMessagingTemplate rabbitMessagingTemplate;
public HeaderSender(RabbitMessagingTemplate rabbitMessagingTemplate) {
this.rabbitMessagingTemplate = rabbitMessagingTemplate;
}
public void send() {
String msg = "Hello World!";
Map<String, Object> headerMap = new HashMap<>();
headerMap.put("h1", "Header1");
headerMap.put("h3", "Header3");
rabbitMessagingTemplate.convertAndSend("headers", "", msg, headerMap);
msg = "My Girl!";
headerMap.clear();
headerMap.put("h1", "Header1");
headerMap.put("h2", "Header2");
rabbitMessagingTemplate.convertAndSend("headers", "", msg, headerMap);
}
}
编写消费者
@Component
public class HeaderReceiver {
@RabbitListener(queues = "#{headersAutoDeleteQueue1.name}")
public void receive1(String in) {
System.out.println("临时队列1接收到消息:" + in);
}
@RabbitListener(queues = "#{headersAutoDeleteQueue2.name}")
public void receive2(String in) {
System.out.println("临时队列2接收到消息:" + in);
}
@RabbitListener(queues = "#{headersAutoDeleteQueue3.name}")
public void receive3(String in) {
System.out.println("临时队列3接收到消息:" + in);
}
}
编写测试方法
@SpringBootTest
public class RabbitTest {
@Autowired
private HeaderSender headerSender;
@Test
public void testHeaderSender() {
headerSender.send();
}
}
从结果中不难看出，My Girl消息3个队列都匹配到headers, 而Hello Word消息只有队列1与3匹配到，毕竟他没有h2头啦
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