【SpringBoot MQ系列教程】RabbitMq 初体验

【SpringBoot MQ系列教程】RabbitMq 初体验

mq 在异步解耦削峰的优势非常突出，现在很多的项目都会用到，掌握 mq 的知识点，了解如何顺畅的使用 mq，可以说是一个必备的职业技能点了

接下来我们进入 rabbitmq 的学习过程

I. 环境准备

在测试之前，需要安装 rabbitmq，下面分别给出 mac + centos 的安装教程

1. mac 安装

安装命令

brew install rabbitmq

## 进入安装目录
cd /usr/local/Cellar/rabbitmq/3.7.5

# 启动
brew services start rabbitmq
# 当前窗口启动
rabbitmq-server

启动控制台之前需要先开启插件

./rabbitmq-plugins enable rabbitmq_management

进入控制台: http://localhost:15672/

用户名和密码：guest,guest

2. centos 安装

安装命令

yum install erlang
wget http://www.rabbitmq.com/releases/rabbitmq-server/v3.6.15/rabbitmq-server-3.6.15-1.el6.noarch.rpm
yum install rabbitmq-server-3.6.15-1.el6.noarch.rpm

插件开启

rabbitmq-plugins enable rabbitmq_management
# 启动
rabbitmq-server -detached

3. 配置

添加账号，设置权限

## 添加账号
./rabbitmqctl add_user admin admin
## 添加访问权限
./rabbitmqctl set_permissions -p "/" admin ".*" ".*" ".*"
## 设置超级权限
./rabbitmqctl set_user_tags admin administrator

4. 项目环境

接下我们创建一个 SpringBoot 项目，用于简单的体验一下 rabbitmq 的发布和消费消息

springboot 版本为2.2.1.RELEASE
rabbitmq 版本为 3.7.5

依赖配置文件 pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.1.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
</properties>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-amqp</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </pluginManagement>
</build>
<repositories>
    <repository>
        <id>spring-snapshots</id>
        <name>Spring Snapshots</name>
        <url>https://repo.spring.io/libs-snapshot-local</url>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
    <repository>
        <id>spring-milestones</id>
        <name>Spring Milestones</name>
        <url>https://repo.spring.io/libs-milestone-local</url>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
    </repository>
    <repository>
        <id>spring-releases</id>
        <name>Spring Releases</name>
        <url>https://repo.spring.io/libs-release-local</url>
        <snapshots>
            <enabled>false</enabled>
        </snapshots>
    </repository>
</repositories>

在application.yml配置文件中，添加 rabbitmq 的相关属性

spring:
  rabbitmq:
    virtual-host: /
    username: admin
    password: admin
    port: 5672

II. 实例演示

接下来我们看一个hello world版本的 rabbitmq 的使用姿势，一个简单发布消息、消费消息

1. 发布消息

消息发布，我们主要借助AmqpTemplate来实现

@Component
public class PublishDemo {
    @Autowired
    private AmqpTemplate amqpTemplate;

    public String publish2mq(String ans) {
        String msg = "hello world = " + ans;
        System.out.println("publish: " + msg);
        amqpTemplate.convertAndSend(Pkg.exchange, Pkg.routing, msg);
        return msg;
    }
}

上面的 case 中，主要方法在于amqpTemplate#convertAndSend，第一个参数为 exchangeName, 第二个为 routingKey

常量配置如下

class Pkg {
    final static String exchange = "topic.e";
    final static String routing = "r";
    final static String queue = "topic.a";
}

2. 消费消息

消费消息，需要指定 Queue，通过 routingKey 绑定 exchange，如下

@Service
public class ConsumerDemo {

    @RabbitListener(bindings = @QueueBinding(value = @Queue(value = Pkg.queue, durable = "false", autoDelete = "true"),
            exchange = @Exchange(value = Pkg.exchange, ignoreDeclarationExceptions = "true",
                    type = ExchangeTypes.TOPIC), key = Pkg.routing))
    public void consumer(String msg) {
        System.out.println("consumer msg: " + msg);
    }
}

3. 测试 demo

写一个简单的 rest 接口，用于接收参数，发布消息到 mq，并被ConsumerDemo消费

@RestController
public class PubRest {
    @Autowired
    private PublishDemo publishDemo;

    @GetMapping(path = {"", "/", "/publish"})
    public String publish(String name) {
        return publishDemo.publish2mq(name);
    }
}