[大数据]rabbitMQ解决消息丢失-手工确认ack

maven配置

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.0</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>SpringbootTest</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>SpringbootTest</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>com.rabbitmq</groupId>
            <artifactId>amqp-client</artifactId>
            <version>5.10.0</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

工具类

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class MqChanneUtils {
    public static Channel getChannel() throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("127.0.0.1");
        factory.setPort(5672);
        factory.setUsername("guest");
        factory.setPassword("guest");
        factory.setVirtualHost("/");
        factory.setConnectionTimeout(20000);
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        return channel;
    }
}

public class SleepUtils {

    public static void sleeper(int i){
        try {
            Thread.sleep(i*1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

生产者

?

public class MessProductor {
    public static void main(String[] args) throws Exception{
        Channel channel = MqChanneUtils.getChannel();

        for(int i = 0; i < 10; i++){
            System.out.println("生产消息:" + i);
            String msg = "Hello RabbitMQ" + i;
            channel.basicPublish("", "test01", null, msg.getBytes());
        }
        //5.记得关闭相关的连接
        channel.close();

    }
}

创建消费者01和02。代码逻辑都是一样的。只不过一个睡眠30s，一个睡眠2秒。这样做为了更好的看到应答效果。在一个消息没应答之前，是无法继续消费消息的。当一个消费者出现问题，比如我停掉01消费者。这时候消费会被02去消费。这样就保证了消息是在被消费后才能从生产者移除。

public class ConsumeConfirm {
    @SneakyThrows
    public static void main(String[] args) {
        Channel channel = MqChanneUtils.getChannel();
        DeliverCallback deliverCallback =(a, delivery)->{
            String receivedMessage = new String(delivery.getBody());
            SleepUtils.sleeper(30); //这里改下时间
            System.out.println(" 接收到消息:"+receivedMessage);
            //应答一个消息，最后false代表只应答当前消息。
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(),false);
        };
        //将通道的应答机制设置手动应答
        boolean autoAck = false;
        channel.basicConsume("test01",autoAck,deliverCallback,consumer->{});
    }
}

?整个效果，01我消费第一条消息后就停掉服务，发现剩下的消息都被02消费了。