java實現隊列和交換機的聲明

在之前我們都是基于RabbitMQ控制臺來創建隊列、交換機。但是在實際開發時，隊列和交換機是程序員定義的，將來項目上線，又要交給運維去創建。那么程序員就需要把程序中運行的所有隊列和交換機都寫下來，交給運維。在這個過程中是很容易出現錯誤的。
因此推薦的做法是由程序啟動時檢查隊列和交換機是否存在，如果不存在自動創建。

3.8.1.基本API

SpringAMQP提供了一個Queue類，用來創建隊列：

SpringAMQP還提供了一個Exchange接口，來表示所有不同類型的交換機：


我們可以自己創建隊列和交換機，不過SpringAMQP還提供了ExchangeBuilder來簡化這個過程：

而在綁定隊列和交換機時，則需要使用BindingBuilder來創建Binding對象：

3.8.2.fanout示例(基于Bean聲明)

在consumer中創建一個類，聲明隊列和交換機：

package com.itheima.consumer.config;import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.FanoutExchange;
import org.springframework.amqp.core.Queue;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class FanoutConfig {/*** 聲明交換機* @return Fanout類型交換機*/@Beanpublic FanoutExchange fanoutExchange(){return new FanoutExchange("hmall.fanout");}/*** 第1個隊列*/@Beanpublic Queue fanoutQueue1(){return new Queue("fanout.queue1");}/*** 綁定隊列和交換機*/@Beanpublic Binding bindingQueue1(Queue fanoutQueue1, FanoutExchange fanoutExchange){return BindingBuilder.bind(fanoutQueue1).to(fanoutExchange);}/*** 第2個隊列*/@Beanpublic Queue fanoutQueue2(){return new Queue("fanout.queue2");}/*** 綁定隊列和交換機*/@Beanpublic Binding bindingQueue2(Queue fanoutQueue2, FanoutExchange fanoutExchange){return BindingBuilder.bind(fanoutQueue2).to(fanoutExchange);}
}

實際測試：

package com.itheima.consumer.config;import org.springframework.amqp.core.*;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class FanoutConfiguration {/*** 聲明fanout類型交換機* @return*/@Beanpublic FanoutExchange fanoutExchange(){// 兩種聲明方法都可以// return ExchangeBuilder.fanoutExchange("hmall.fanout2").build();return new FanoutExchange("hmall.fanout2");}/*** 聲明默認持久化的fanout.queue3隊列* @return*/@Beanpublic Queue fanoutQueue3(){// 兩種聲明方法都可以// return QueueBuilder.durable("fanout.queue3").build();return new Queue("fanout.queue3");}/*** 綁定隊列和交換機* @param fanoutExchange* @param fanoutQueue3* @return*/@Beanpublic Binding fanoutBinding3(FanoutExchange fanoutExchange,Queue fanoutQueue3){return BindingBuilder.bind(fanoutQueue3).to(fanoutExchange);}/*** 聲明默認持久化的fanout.queue4隊列* @return*/@Beanpublic Queue fanoutQueue4(){// 兩種聲明方法都可以return QueueBuilder.durable("fanout.queue4").build();
//        return new Queue("fanout.queue4");}/*** 綁定隊列和交換機* @return*/@Beanpublic Binding fanoutBinding4(){return BindingBuilder.bind(fanoutQueue4()).to(fanoutExchange());}
}

3.8.2.direct示例(基于Bean聲明)

direct模式由于要綁定多個KEY，會非常麻煩，每一個Key都要編寫一個binding：

package com.itheima.consumer.config;import org.springframework.amqp.core.*;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
public class DirectConfig {/*** 聲明交換機* @return Direct類型交換機*/@Beanpublic DirectExchange directExchange(){return ExchangeBuilder.directExchange("hmall.direct").build();}/*** 第1個隊列*/@Beanpublic Queue directQueue1(){return new Queue("direct.queue1");}/*** 綁定隊列和交換機*/@Beanpublic Binding bindingQueue1WithRed(Queue directQueue1, DirectExchange directExchange){return BindingBuilder.bind(directQueue1).to(directExchange).with("red");}/*** 綁定隊列和交換機*/@Beanpublic Binding bindingQueue1WithBlue(Queue directQueue1, DirectExchange directExchange){return BindingBuilder.bind(directQueue1).to(directExchange).with("blue");}/*** 第2個隊列*/@Beanpublic Queue directQueue2(){return new Queue("direct.queue2");}/*** 綁定隊列和交換機*/@Beanpublic Binding bindingQueue2WithRed(Queue directQueue2, DirectExchange directExchange){return BindingBuilder.bind(directQueue2).to(directExchange).with("red");}/*** 綁定隊列和交換機*/@Beanpublic Binding bindingQueue2WithYellow(Queue directQueue2, DirectExchange directExchange){return BindingBuilder.bind(directQueue2).to(directExchange).with("yellow");}
}

3.8.4.基于注解聲明

基于@Bean的方式聲明隊列和交換機比較麻煩，Spring還提供了基于注解方式來聲明。

注意聲明的文件是Listener下的，在監聽者位置聲明

例如，我們同樣聲明Direct模式的交換機和隊列：

@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "direct.queue1"),exchange = @Exchange(name = "hmall.direct", type = ExchangeTypes.DIRECT),key = {"red", "blue"}
))
public void listenDirectQueue1(String msg){System.out.println("消費者1接收到direct.queue1的消息：【" + msg + "】");
}@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "direct.queue2"),exchange = @Exchange(name = "hmall.direct", type = ExchangeTypes.DIRECT),key = {"red", "yellow"}
))
public void listenDirectQueue2(String msg){System.out.println("消費者2接收到direct.queue2的消息：【" + msg + "】");
}

是不是簡單多了。
再試試Topic模式：

@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "topic.queue1"),exchange = @Exchange(name = "hmall.topic", type = ExchangeTypes.TOPIC),key = "china.#"
))
public void listenTopicQueue1(String msg){System.out.println("消費者1接收到topic.queue1的消息：【" + msg + "】");
}@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "topic.queue2"),exchange = @Exchange(name = "hmall.topic", type = ExchangeTypes.TOPIC),key = "#.news"
))
public void listenTopicQueue2(String msg){System.out.println("消費者2接收到topic.queue2的消息：【" + msg + "】");
}

小結