Spring Boot异步消息之AMQP讲解及实战（附源码）

Posted 2022-11-26 showswoller

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AMQP（高级消息队列协议）是一个提供统一消息服务的应用层标准高级消息队列协议。是应用层协议的一个开放标准，为面向消息的中间件设计。基于此协议的客户端与消息中间件可 传递消息，并不受客户端/中间件的不同产品，不同开发语言等条件的限制。

下面实现主要用RabbitMQ讲解AMQP实例，因此需要事先安装RabbitMQ和erlang语言

erlang下载地址 https://www.erlang.org/downloads

RabbitMQ下载地址 https://www.rabbitmq.com/download.html 

使用RabbitMQ实现发布/订阅异步消息模式

1：创建发布者应用ch8_2Sender

2：在pom.xml文件中添加依赖

<?xml version="1.0" encoding="UTF-8"?>

-<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://maven.apache.org/POM/4.0.0">

<modelVersion>4.0.0</modelVersion>


-<parent>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>2.1.8.RELEASE</version>

<relativePath/>

<!-- lookup parent from repository -->


</parent>

<groupId>com.ch</groupId>

<artifactId>ch8_2Sender</artifactId>

<version>0.0.1-SNAPSHOT</version>

<name>ch8_2Sender</name>

<description>Demo project for Spring Boot</description>


+<properties>


-<dependencies>


-<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-amqp</artifactId>

</dependency>


+<dependency>


-<dependency>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-test</artifactId>

<scope>test</scope>

</dependency>


-<dependency>

<groupId>org.springframework.amqp</groupId>

<artifactId>spring-rabbit-test</artifactId>

<scope>test</scope>

</dependency>

</dependencies>


-<build>


-<plugins>


-<plugin>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-maven-plugin</artifactId>

</plugin>

</plugins>

</build>

</project>

 3：创建Weather实体类

package com.ch.ch8_2Sender.entity;
import java.io.Serializable;
public class Weather implements Serializable
	private static final long serialVersionUID = -8221467966772683998L;
	private String id;
	private String city;
	private String weatherDetail;
	public String getCity() 
		return city;
	
	public void setCity(String city) 
		this.city = city;
	
	public String getWeatherDetail() 
		return weatherDetail;
	
	public void setWeatherDetail(String weatherDetail) 
		this.weatherDetail = weatherDetail;
	
	public String getId() 
		return id;
	
	public void setId(String id) 
		this.id = id;
	
	@Override
	public String toString() 
		return "Weather [id=" + id + ", city=" + city + ", weatherDetail=" + weatherDetail + "]";
	

4：重写Ch82SenderApplication主类

package com.ch.ch8_2Sender;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageBuilder;
import org.springframework.amqp.core.MessageDeliveryMode;
import org.springframework.amqp.rabbit.connection.CorrelationData;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.amqp.support.converter.Jackson2JsonMessageConverter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import com.ch.ch8_2Sender.entity.Weather;
import com.fasterxml.jackson.databind.ObjectMapper;
@SpringBootApplication
public class Ch82SenderApplication implements CommandLineRunner 
	@Autowired
    private ObjectMapper objectMapper;
	@Autowired 
	RabbitTemplate rabbitTemplate;
	public static void main(String[] args) 
		SpringApplication.run(Ch82SenderApplication.class, args);
	
	/**
	 * 定义发布者
	 */
	@Override
	public void run(String... args) throws Exception 
		//定义消息对象
		Weather weather = new Weather();
		weather.setId("010");
		weather.setCity("北京");
		weather.setWeatherDetail("今天晴到多云，南风5-6级，温度19-26°C");
		//指定Json转换器，Jackson2JsonMessageConverter默认将消息转换成byte[]类型的消息
		rabbitTemplate.setMessageConverter(new Jackson2JsonMessageConverter());
		//objectMapper将weather对象转换为JSON字节数组
		Message msg=MessageBuilder.withBody(objectMapper.writeValueAsBytes(weather))
				.setDeliveryMode(MessageDeliveryMode.NON_PERSISTENT)
                .build();
        // 消息唯一ID
        CorrelationData correlationData = new CorrelationData(weather.getId());
		//使用已封装好的convertAndSend(String exchange , String routingKey , Object message, CorrelationData correlationData)
		//将特定的路由key发送消息到指定的交换机
		rabbitTemplate.convertAndSend(
				"weather-exchange", //分发消息的交换机名称
				"weather.message", //用来匹配消息的路由Key
				msg, //消息体
				correlationData);
	

5：创建订阅者应用ch8_2Receiver-1

package com.ch.ch8_2Receiver1;
import org.springframework.amqp.rabbit.annotation.Exchange;
import org.springframework.amqp.rabbit.annotation.Queue;
import org.springframework.amqp.rabbit.annotation.QueueBinding;
import org.springframework.amqp.rabbit.annotation.RabbitHandler;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.handler.annotation.Payload;
import org.springframework.stereotype.Component;
import com.fasterxml.jackson.databind.ObjectMapper;
/**
 * 定义订阅者Receiver1
 */
@Component
public class Receiver1 
	@Autowired
    private ObjectMapper objectMapper;
	@RabbitListener(
			bindings = 
			@QueueBinding(
				//队列名weather-queue1保证和别的订阅者不一样
				value = @Queue(value = "weather-queue1",durable = "true"),
				//weather-exchange与发布者的交换机名相同
				exchange = @Exchange(value = "weather-exchange",durable = "true",type = "topic"),
				//weather.message与发布者的消息的路由Key相同
				key = "weather.message"
			)	
    )
    @RabbitHandler
    public void receiveWeather(@Payload byte[] weatherMessage)throws Exception
        System.out.println("-----------订阅者Receiver1接收到消息--------");
        //将JSON字节数组转换为Weather对象
        Weather w=objectMapper.readValue(weatherMessage, Weather.class);
        System.out.println("Receiver1收到的消息内容："+w);
    

6:创建订阅者应用ch8_2Receiver-2

package com.ch.ch8_2Receiver1;
import org.springframework.amqp.rabbit.annotation.Exchange;
import org.springframework.amqp.rabbit.annotation.Queue;
import org.springframework.amqp.rabbit.annotation.QueueBinding;
import org.springframework.amqp.rabbit.annotation.RabbitHandler;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.handler.annotation.Payload;
import org.springframework.stereotype.Component;
import com.fasterxml.jackson.databind.ObjectMapper;
/**
 * 定义订阅者Receiver2
 */
@Component
public class Receiver2 
	@Autowired
    private ObjectMapper objectMapper;
	@RabbitListener(
			bindings = 
			@QueueBinding(
				//队列名weather-queue2保证和别的订阅者不一样
				value = @Queue(value = "weather-queue2",durable = "true"),
				//weather-exchange与发布者的交换机名相同
				exchange = @Exchange(value = "weather-exchange",durable = "true",type = "topic"),
				//weather.message与发布者的消息的路由Key相同
				key = "weather.message"
			)	
    )
    @RabbitHandler
    public void receiveWeather(@Payload byte[] weatherMessage)throws Exception
        System.out.println("-----------订阅者Receiver2接收到消息--------");
        Weather w=objectMapper.readValue(weatherMessage, Weather.class);
        //将JSON字节数组转换为Weather对象
        System.out.println("Receiver2收到的消息内容："+w);
     
    

接下来分别运行发布者和订阅者的主类即可，发现一个发布者发布的消息可以被多个订阅者订阅。