05. RabbitMQ的消息持久化

05. RabbitMQ的消息持久化

• 消息的可靠性是RabbitMQ的一大特色，那么RabbitMQ是如何避免消息丢失？

• • 消费者的ACK确认机制，可以防止消费者丢失消息
  • 万一在消费者消费之前，RabbitMQ服务器宕机了，那消息也会丢失

• 想要将消息持久化， 必须将路由、队列和发送消息方法都要持久化才可以（所谓持久化，就是将消息写入到磁盘中。当由于mq服务器宕机，或者程序异常停止，重新启动依然可以读取到之前发送的消息）

1. 整合发布/订阅模式的持久化

生产者代码

package presistent;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.MessageProperties;
import util.ConnectionUtil;

/**
 * @author WeiHong
 * @date 2021 -  09 - 14 16:44
 * 消息持久化
 */
public class sender {
    public static void main(String[] args) throws Exception {
        //1.获取连接
        Connection connection = ConnectionUtil.getConnection();
        //2.在连接中建立信道
        Channel channel = connection.createChannel();
        //3.声明路由
        //参数1：路由名
        //参数2：路由键类型
        //参数3：是否持久化
        channel.exchangeDeclare("prisistent_exchange_test","fanout",true);
        //4.发送消息
        String msg = "hello";
        channel.basicPublish("prisistent_exchange_test","", MessageProperties.PERSISTENT_TEXT_PLAIN,msg.getBytes());
        System.out.println("发送的消息为：" + msg);
        channel.close();
        connection.close();

    }
}

消费者1代码

package presistent;

import com.rabbitmq.client.*;
import util.ConnectionUtil;

import java.io.IOException;

/**
 * @author WeiHong
 * @date 2021 -  09 - 14 16:56
 */
public class recer1 {
    public static void main(String[] args) throws Exception {
        //1.建立连接
        Connection connection = ConnectionUtil.getConnection();
        //2.在连接中建立信道
        Channel channel = connection.createChannel();
        //2.1声明队列
        channel.queueDeclare("prisistent_exchange_queuq1",true,false,false,null);
        //2.2通过队列绑定路由
        channel.queueBind("prisistent_exchange_queuq1","prisistent_exchange_test","");
        //3定义内部类实现handDclare接收消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String msg = new String(body);
                System.out.println("【消费者1】="+msg);
            }

        };

        //4.监听队列
        channel.basicConsume("prisistent_exchange_queuq1",true,consumer);
    }

}

消费者2代码

package presistent;

import com.rabbitmq.client.*;
import util.ConnectionUtil;

import java.io.IOException;

/**
 * @author WeiHong
 * @date 2021 -  09 - 14 16:56
 */
public class recer2 {
    public static void main(String[] args) throws Exception {
        //1.建立连接
        Connection connection = ConnectionUtil.getConnection();
        //2.在连接中建立信道
        Channel channel = connection.createChannel();
        //2.1声明队列
        channel.queueDeclare("prisistent_exchange_queuq2",true,false,false,null);
        //2.2通过队列绑定路由
        channel.queueBind("prisistent_exchange_queuq2","prisistent_exchange_test","");
        //3定义内部类实现handDclare接收消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String msg = new String(body);
                System.out.println("【消费者2】="+msg);
            }

        };

        //4.监听队列
        channel.basicConsume("prisistent_exchange_queuq2",true,consumer);
    }

}

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