RabbitMQ日常(一)HelloWorld之模擬收發消息

下圖爲一個簡易的RabbitMQ流程草圖，RabbitMQ一般流程爲：

1. 由生產者創建消息後，放置在（交換機）exchange中
2. RabbitMQ通過相關配置綁定exchange和queue（隊列）
3. 消費者通過channel（管道）獲取channel中的消息
   

實驗環境：

1. rabbitmq 3.7.14（使用rpm安裝）

主要步驟爲：

1. 創建一個Springboot項目，小白請自行百度
2. 通過maven的pom文件引入相關依賴jar包
3. 編寫生產端、消費端代碼

• pom.xml文件

<?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>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.rabbitMQ</groupId>
    <artifactId>mq_demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mq_demo</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-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.rabbitmq</groupId>
            <artifactId>amqp-client</artifactId>
            <version>5.6.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

生產者代碼

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

public class Produce {

    public static void main(String[] args) throws Exception{
        ConnectionFactory connectionFactory= new ConnectionFactory();
        connectionFactory.setHost("你的主機IP");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection=connectionFactory.newConnection();

        Channel channel=connection.createChannel();
        String msg="This is a message2!";
        //這裏的test01爲隊列名稱
        channel.basicPublish("","test01",null,msg.getBytes());
        channel.close();
        connection.close();

    }
}

消費者代碼

package com.new_rabbitmq;

import com.rabbitmq.client.*;
import com.rabbitmq.client.impl.AMQImpl;

import java.io.IOException;

public class Consumer {

    public static void main(String[] args) throws Exception{
        //創建鏈接
        ConnectionFactory connectionFactory= new ConnectionFactory();
        connectionFactory.setHost("你的主機IP");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");
        Connection connection=connectionFactory.newConnection();
        //創建一個管道
        Channel channel=connection.createChannel();
        // 聲明一個隊列
        channel.queueDeclare("test01",true,false,false,null);
        // 創建消費者
        DefaultConsumer consumer= new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                //super.handleDelivery(consumerTag, envelope, properties, body);
                String message = new String(body, "utf-8");
                System.out.println("[Receive]：" + message);
            }
        };
        channel.basicConsume("test01",true,consumer);
	/*
	//創建消費者的第二種方式
        DeliverCallback deliverCallback = (consumer, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" + message + "'");
        };
        channel.basicConsume(queueName, true, deliverCallback, consumer -> { });
    */
    }
}

總結：

1. 上面總結了兩種創建consumer的方法（雖然是官網抄的），但重點是 channel.basicConsume(“test01”,true,consumer); 這裏的true是代表自動簽收（生產一般不用自動簽收）。
2. 根據rabbitMQ的原理：我們這裏需要先啓動消費者端，再啓動生產端，纔可以看到消費者監聽隊列的效果！