簡單消息監聽容器--SimpleMessageListenerContainer

這個類非常強大，我們可以對他做很多設置，對於消費者的配置項，這個類都可以滿足
監聽隊列（多個隊列）、自動啟動、自動聲明功能
可以設置事務特性、事務管理器、事務屬性、事務容量（並發）、是否開啟事務、回滾消息等
可以設置消費者數量、最大最小數量、批量消費
設置消息確認和自動確認模式、是否重回隊列、異常捕獲handler函數
設置消費者標簽生成策略、是否獨占模式、消費者屬性等
設置具體的轉換器、消息轉換器等
很多基於RabbitMQ的自制定化后端管控台在進行動態配置的時候，也是根據這一特性去實現的。
注意：SimpleMessageListenerContainer可以進行動態設置，比如在運行中的應用可以動態
修改其消費者數量的大小、接收消息的模式等

SimpleMessageListenerContainer為什么可以進行動態感知設置變更？

package com.dwz.spring;

import java.util.UUID;

import org.springframework.amqp.core.AcknowledgeMode;
import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.core.TopicExchange;
import org.springframework.amqp.rabbit.connection.CachingConnectionFactory;
import org.springframework.amqp.rabbit.connection.ConnectionFactory;
import org.springframework.amqp.rabbit.core.RabbitAdmin;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer;
import org.springframework.amqp.rabbit.listener.api.ChannelAwareMessageListener;
import org.springframework.amqp.support.ConsumerTagStrategy;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

import com.rabbitmq.client.Channel;

@Configuration
@ComponentScan("com.dwz.spring.*")
public class RabbitMQConfig {
    
    @Bean
    public ConnectionFactory connectionFactory() {
        CachingConnectionFactory connectionFactory = new CachingConnectionFactory();
        connectionFactory.setAddresses("127.0.0.1:5672");
        connectionFactory.setVirtualHost("/vhost_dwz");
        connectionFactory.setUsername("root_dwz");
        connectionFactory.setPassword("123456");
        return connectionFactory;
    }
    
    @Bean
    public RabbitAdmin rabbitAdmin(ConnectionFactory connectionFactory) {
        RabbitAdmin rabbitAdmin = new RabbitAdmin(connectionFactory);
        System.err.println("RabbitAdmin啟動了。。。");
        //設置啟動spring容器時自動加載這個類(這個參數現在默認已經是true，可以不用設置)
        rabbitAdmin.setAutoStartup(true);
        return rabbitAdmin;
    }
    
    @Bean
    public RabbitTemplate rabbitTemplate(ConnectionFactory connectionFactory) {
        RabbitTemplate rabbitTemplate = new RabbitTemplate(connectionFactory);
        return rabbitTemplate;
    }
    
    /**
     *     針對消費者的配置
     * 1.設置交換機的類型
     * 2.將隊列綁定到交換機
     * FanoutExchange:將消息分發到所有綁定的隊列，無routingkey的概念
     * TopicExchange:多關鍵字匹配
     * HeadersExchange：通過添加屬性key-value匹配
     * DirectExchange:按照routingkey分發到指定隊列
     */
    @Bean
    public TopicExchange exchange001() {
        return new TopicExchange("topic001", true, false);
    }
    
    @Bean
    public Queue queue001() {
        return new Queue("queue001", true);//隊列持久化
    }
    
    @Bean
    public Binding binding001() {
        return BindingBuilder.bind(queue001()).to(exchange001()).with("spring.*");
    }
    
    @Bean
    public TopicExchange exchange002() {
        return new TopicExchange("topic002", true, false);
    }
    
    @Bean
    public Queue queue002() {
        return new Queue("queue002", true);//隊列持久化
    }
    
    @Bean
    public Binding binding002() {
        return BindingBuilder.bind(queue002()).to(exchange002()).with("rabbit.*");
    }
    
    @Bean
    public TopicExchange exchange003() {
        return new TopicExchange("topic003", true, false);
    }
    
    @Bean
    public Queue queue003() {
        return new Queue("queue003", true);//隊列持久化
    }
    
    @Bean
    public Binding binding003() {
        return BindingBuilder.bind(queue003()).to(exchange003()).with("mq.*");
    }
    
    @Bean
    public Queue queue_image() {
        return new Queue("image_queue", true);//隊列持久化
    }
    
    @Bean
    public Queue queue_pdf() {
        return new Queue("pdf_queue", true);//隊列持久化
    }
    
    /*
     *     簡單消息監聽容器
     */
    @Bean
    public SimpleMessageListenerContainer messageContainer(ConnectionFactory connectionFactory) {
        SimpleMessageListenerContainer container = new SimpleMessageListenerContainer(connectionFactory);
        //同時監聽多個隊列
        container.setQueues(queue001(), queue002(), queue003(), queue_image(), queue_pdf());
        //設置當前的消費者數量
        container.setConcurrentConsumers(1);
        container.setMaxConcurrentConsumers(5);
        //設置是否重回隊列
        container.setDefaultRequeueRejected(false);
        //設置自動簽收
        container.setAcknowledgeMode(AcknowledgeMode.AUTO);
        //設置監聽外露
        container.setExposeListenerChannel(true);
        //設置消費端標簽策略
        container.setConsumerTagStrategy(new ConsumerTagStrategy() {
            @Override
            public String createConsumerTag(String queue) {
                return queue + "_" + UUID.randomUUID().toString();
            }
        });
        //設置消息監聽
        container.setMessageListener(new ChannelAwareMessageListener() {
            @Override
            public void onMessage(Message message, Channel channel) throws Exception {
                String msg = new String(message.getBody(), "utf-8");
                System.out.println("-----------消費者：" + msg);
            }
        });
        return container;
    }
}

 自定義消費端標簽策略效果圖：