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1、过期消息（死信）

过期消息也叫TTL消息，TTL：Time To Live
消息的过期时间有两种设置方式：设置单条消息的过期时间和通过队列属性设置消息过期时间

2、设置消息过期的两种方式

队列的过期时间决定了在没有任何消费者的情况下，队列中的消息可以存活多久；
注意事项：如果消息和对列都设置过期时间，则消息的TTL以两者之间较小的那个数值为准。

2.1、设置单条消息的过期时间

2.1.1、配置文件application.yml

server:port: 8080
spring:application:name: ttl-test01rabbitmq:host: 你的服务器IPport: 5672username: 你这账号password: 你的密码virtual-host: powermy:exchangeName: exchange.ttl.aqueueName: queue.ttl.a

2.1.2、配置类RabbitConfig

package com.power.config;import org.springframework.amqp.core.*;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class RabbitConfig {@Value("${my.exchangeName}")private String exchangeName;@Value("${my.queueName}")private String queueName;//创建交换机@Beanpublic DirectExchange directExchange(){return ExchangeBuilder.directExchange(exchangeName).build();}//创建队列@Beanpublic Queue queue(){return QueueBuilder.durable(queueName).build();}@Beanpublic Binding binding(DirectExchange exchangeName,Queue queueName){return BindingBuilder.bind(queueName).to(exchangeName).with("info");}
}

2.1.3、发送消息业务类service（核心代码）

package com.power.service;import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageBuilder;
import org.springframework.amqp.core.MessageProperties;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Service;import javax.annotation.Resource;
import java.util.Date;@Service
@Slf4j
public class MessageService {@Resourceprivate RabbitTemplate rabbitTemplate;@Beanpublic void sendMsg(){//设置消息过期的核心代码MessageProperties messageProperties = new MessageProperties();messageProperties.setExpiration("30000");//设置消息过期时间Message message = MessageBuilder.withBody("hello world".getBytes()).andProperties(messageProperties).build();rabbitTemplate.convertAndSend("exchange.ttl.a","info",message);log.info("消息发送完毕，发送时间是："+new Date());}
}

2.1.4、启动类

package com.power;import com.power.service.MessageService;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;import javax.annotation.Resource;@SpringBootApplication
public class Application implements ApplicationRunner {@Resourceprivate MessageService messageService;public static void main(String[] args) {SpringApplication.run(Application.class);}@Overridepublic void run(ApplicationArguments args) throws Exception {messageService.sendMsg();}
}

2.1.5、依赖文件pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.power</groupId><artifactId>rabbit_05_ttl01</artifactId><version>1.0-SNAPSHOT</version><name>rabbit_05_ttl01</name><!-- FIXME change it to the project's website --><url>http://www.example.com</url><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.6.13</version><relativePath/></parent><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.24</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

2.1.6、测试

启动项目：

登录rabbitmq后台：
在消息有效期内，可以获取到消息。

超过消息有效期，获取不到消息。

2.2、通过队列属性设置消息过期时间

2.1.1、配置文件application.yml

server:port: 8080
spring:application:name: ttl-test02rabbitmq:host: 你的服务器IPport: 5672username: 你这账号password: 你的密码virtual-host: powermy:exchangeName: exchange.ttl.bqueueName: queue.ttl.b

2.1.2、配置类RabbitConfig（核心代码）

package com.power.config;import org.springframework.amqp.core.*;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import java.util.HashMap;
import java.util.Map;@Configuration
public class RabbitConfig {@Value("${my.exchangeName}")private String exchangeName;@Value("${my.queueName}")private String queueName;//创建交换机@Beanpublic DirectExchange directExchange(){return ExchangeBuilder.directExchange(exchangeName).build();}//创建队列@Beanpublic Queue queue(){//设置队列消息的过期时间，超过这个有效期，队列内的所有消息都会过期//方式1：new Queue的方式Map<String, Object> arguments = new HashMap<>();arguments.put("x-message-ttl",30000);return new Queue(queueName,true,false,false,arguments);//        方式2：建造者方式
//        return QueueBuilder.durable(queueName).withArguments(arguments).build();}@Beanpublic Binding binding(DirectExchange exchangeName,Queue queueName){return BindingBuilder.bind(queueName).to(exchangeName).with("info");}
}

2.2.3、发送消息业务类service

package com.power.service;import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageBuilder;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Service;import javax.annotation.Resource;
import java.util.Date;@Service
@Slf4j
public class MessageService {@Resourceprivate RabbitTemplate rabbitTemplate;@Beanpublic void sendMsg(){Message message = MessageBuilder.withBody("hello world".getBytes()).build();rabbitTemplate.convertAndSend("exchange.ttl.b","info",message);log.info("消息发送完毕，发送时间是："+new Date());}
}

2.2.4、启动类

package com.power;import com.power.service.MessageService;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;import javax.annotation.Resource;@SpringBootApplication
public class Application implements ApplicationRunner {@Resourceprivate MessageService messageService;public static void main(String[] args) {SpringApplication.run(Application.class);}@Overridepublic void run(ApplicationArguments args) throws Exception {messageService.sendMsg();}
}

2.2.5、依赖文件pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.power</groupId><artifactId>rabbit_05_ttl02</artifactId><version>1.0-SNAPSHOT</version><name>rabbit_05_ttl02</name><!-- FIXME change it to the project's website --><url>http://www.example.com</url><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.6.13</version><relativePath/></parent><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.24</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build></project>

2.2.6、测试

启动项目：
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