基于spring-boot 2.*
作用:
1、异步处理
2、应用解耦
3、流量削峰
相关概念介绍:
Broker:它提供一种传输服务,它的角色就是维护一条从生产者到消费者的路线,保证数据能按照指定的方式进行传输,
Exchange:消息交换机,它指定消息按什么规则,路由到哪个队列。
Queue:消息的载体,每个消息都会被投到一个或多个队列。
Binding:绑定,它的作用就是把exchange和queue按照路由规则绑定起来.
Routing Key:路由关键字,exchange根据这个关键字进行消息投递。
vhost:虚拟主机,一个broker里可以有多个vhost,用作不同用户的权限分离。
Producer:消息生产者,就是投递消息的程序.
Consumer:消息消费者,就是接受消息的程序.
Channel:消息通道,在客户端的每个连接里,可建立多个channel.
添加依赖:
org.springframework.boot spring-boot-starter-amqp
spring-boot配置:
# =========消息队列(消息总线用)========= spring: rabbitmq: host: ${RABBIT_MQ_HOST:192.168.2.166} port: ${RABBIT_MQ_PORT:5672} username: guest password: guest virtual-host: /
生产者实例代码:
创建消息生产者Sender。通过注入AmqpTemplate接口的实例来实现消息的发送,AmqpTemplate接口定义了一套针对AMQP协议的基础操作。在Spring Boot中会根据配置来注入其具体实现。在该生产者,我们会产生一个字符串,并发送到名为hello的队列中。
import java.util.Date; import org.springframework.amqp.core.AmqpTemplate; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; @Component public class Sender { @Autowired private AmqpTemplate rabbitTemplate; public void send() { String context = "hello " + new Date(); System.out.println("Sender : " + context); this.rabbitTemplate.convertAndSend("hello", context); } }
创建消息消费者Receiver。通过@RabbitListener注解定义该类对hello队列的监听,并用@RabbitHandler注解来指定对消息的处理方法。所以,该消费者实现了对hello队列的消费,消费操作为输出消息的字符串内容。
import org.springframework.amqp.rabbit.annotation.RabbitHandler; import org.springframework.amqp.rabbit.annotation.RabbitListener; import org.springframework.stereotype.Component; @Component @RabbitListener(queues = "hello") public class Receiver { @RabbitHandler public void process(String hello) { System.out.println("Receiver : " + hello); } }
创建RabbitMQ的配置类RabbitConfig,用来配置队列、交换器、路由等高级信息。这里我们以入门为主,先以最小化的配置来定义,以完成一个基本的生产和消费过程。
import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import com.rabbitmq.client.impl.AMQImpl.Queue; //这里可以配置具体的队列 @Configuration public class RabbitConfig { @Bean public Queue helloQueue() { return new Queue(); } }
完整配置如下:
@Configuration public class RabbitConfig { private final Logger logger = LoggerFactory.getLogger(this.getClass()); @Value("${spring.rabbitmq.host}") private String host; @Value("${spring.rabbitmq.port}") private int port; @Value("${spring.rabbitmq.username}") private String username; @Value("${spring.rabbitmq.password}") private String password; public static final String EXCHANGE_A = "my-mq-exchange_A"; public static final String EXCHANGE_B = "my-mq-exchange_B"; public static final String EXCHANGE_C = "my-mq-exchange_C"; public static final String QUEUE_A = "QUEUE_A"; public static final String QUEUE_B = "QUEUE_B"; public static final String QUEUE_C = "QUEUE_C"; public static final String ROUTINGKEY_A = "spring-boot-routingKey_A"; public static final String ROUTINGKEY_B = "spring-boot-routingKey_B"; public static final String ROUTINGKEY_C = "spring-boot-routingKey_C"; @Bean public ConnectionFactory connectionFactory() { CachingConnectionFactory connectionFactory = new CachingConnectionFactory(host,port); connectionFactory.setUsername(username); connectionFactory.setPassword(password); connectionFactory.setVirtualHost("/"); connectionFactory.setPublisherConfirms(true); return connectionFactory; } @Bean @Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE) //必须是prototype类型 public RabbitTemplate rabbitTemplate() { RabbitTemplate template = new RabbitTemplate(connectionFactory()); return template; } /** * 针对消费者配置 * 1. 设置交换机类型 * 2. 将队列绑定到交换机 FanoutExchange: 将消息分发到所有的绑定队列,无routingkey的概念 HeadersExchange :通过添加属性key-value匹配 DirectExchange:按照routingkey分发到指定队列 TopicExchange:多关键字匹配 */ @Bean public DirectExchange defaultExchange() { return new DirectExchange(EXCHANGE_A); } /** * 获取队列A * @return */ @Bean public Queue queueA() { return new Queue(QUEUE_A, true); //队列持久 } @Bean public Binding binding() { return BindingBuilder.bind(queueA()).to(defaultExchange()).with(RabbitConfig.ROUTINGKEY_A); } @Bean public Binding bindingB(){ return BindingBuilder.bind(queueB()).to(defaultExchange()).with(RabbitConfig.ROUTINGKEY_B); } }
生产者代码如下:
@Component public class MsgProducer implements RabbitTemplate.ConfirmCallback { private final Logger logger = LoggerFactory.getLogger(this.getClass()); //由于rabbitTemplate的scope属性设置为ConfigurableBeanFactory.SCOPE_PROTOTYPE,所以不能自动注入 private RabbitTemplate rabbitTemplate; /** * 构造方法注入rabbitTemplate */ @Autowired public MsgProducer(RabbitTemplate rabbitTemplate) { this.rabbitTemplate = rabbitTemplate; rabbitTemplate.setConfirmCallback(this); //rabbitTemplate如果为单例的话,那回调就是最后设置的内容 } public void sendMsg(String content) { CorrelationData correlationId = new CorrelationData(UUID.randomUUID().toString()); //把消息放入ROUTINGKEY_A对应的队列当中去,对应的是队列A rabbitTemplate.convertAndSend(RabbitConfig.EXCHANGE_A, RabbitConfig.ROUTINGKEY_A, content, correlationId); } /** * 回调 */ @Override public void confirm(CorrelationData correlationData, boolean ack, String cause) { logger.info(" 回调id:" + correlationData); if (ack) { logger.info("消息成功消费"); } else { logger.info("消息消费失败:" + cause); } } }
消费者代码如下:
@Component @RabbitListener(queues = RabbitConfig.QUEUE_A) public class MsgReceiver { private final Logger logger = LoggerFactory.getLogger(this.getClass()); @RabbitHandler public void process(String content) { logger.info("接收处理队列A当中的消息: " + content); } }