RabbitMQ系列(三)--Java API

基于java使用RabbitMQ

框架：SpringBoot1.5.14.RELEASE

maven依赖：

<dependency>
    <groupId>com.rabbitmq</groupId>
    <artifactId>amqp-client</artifactId>
    <version>3.6.5</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-amqp</artifactId>
</dependency>

本文只是操作原生RabbitMQ，并没有和SpringBoot进行整合，后面介绍整合，基于注解使用

一、quick start

1.1、Consumer

public static void main(String[] args) throws Exception{
        //1 创建一个ConnectionFactory, 并进行配置
        ConnectionFactory factory = new ConnectionFactory();
        factory.setVirtualHost("/");
        factory.setHost("139.196.75.238");
        factory.setPort(5672);
        //2 通过连接工厂创建连接
        Connection connection = factory.newConnection();
        //3 通过connection创建一个Channel
        Channel channel = connection.createChannel();

        //4 声明（创建）一个队列
        channel.queueDeclare("test002", true, false, false, null);

        //5 创建消费者
        QueueingConsumer queueingConsumer = new QueueingConsumer(channel);

        //6 设置Channel
        channel.basicConsume("test002", true, queueingConsumer);

        while(true){
            //7 获取消息
            QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();
            String msg = new String(delivery.getBody());
            log.info(msg);
        }
    }
}

参数解释：

　　durable：是否持久化，Durable：是，即使服务器重启，这个队列也不会消失，Transient：否

　　exclusive：这个queue只能由一个exchange监听restricted to this connection，使用场景：顺序消费

　　autoDelete：当最后一个Binding到Exchange的Queue删除之后，自动删除该Exchange

　　arguments：参数

　　autoACK：是否自动签收，对应着手动签收

1.2、Producer

public class Producer {

    public static void main(String[] args) throws Exception{
        //1 创建一个ConnectionFactory, 并进行配置
        ConnectionFactory factory = new ConnectionFactory();
        factory.setVirtualHost("/");
        factory.setHost("139.196.75.238");
        factory.setPort(5672);
        //2 通过连接工厂创建连接
        Connection connection = factory.newConnection();
        //3 通过connection创建一个Channel
        Channel channel = connection.createChannel();
        //4 通过Channel发送数据
        for(int i=0; i < 5; i++){
            String msg = "Hello RabbitMQ!";
            //1 exchange   2 routingKey
            channel.basicPublish("", "test002", null, msg.getBytes());
        }
        //5 关闭相关的连接
        channel.close();
        factory.clone();
    }
}

参数解释：

　　exchange name：

　　routingKey：路由规则

　　BasicProperties：

　　body：message中的body

结果：

17:43:49.351 [main] INFO com.it.quickstart.Consumer - Hello RabbitMQ!
17:43:49.351 [main] INFO com.it.quickstart.Consumer - Hello RabbitMQ!
17:43:49.351 [main] INFO com.it.quickstart.Consumer - Hello RabbitMQ!
17:43:49.351 [main] INFO com.it.quickstart.Consumer - Hello RabbitMQ!
17:43:49.351 [main] INFO com.it.quickstart.Consumer - Hello RabbitMQ!

　　我们使用RabbitMQ，需要首先在可视化界面确定queue，exchange是否创建，对应关系是否正常，这是一个大前提

1.3、自定义消费者

　　之前接收message，通过while(true)，感觉太low了，RabbitMQ支持实现自定义消费者，只需要集成DefaultConsumer，重写handlerDelivery，

构造器

public class MyConsumer extends DefaultConsumer {
    public MyConsumer(Channel channel) {
        super(channel);
    }

    @Override
    public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
        System.err.println("-----------consume message----------");
        System.err.println("consumerTag: " + consumerTag);
        System.err.println("envelope: " + envelope);
        System.err.println("properties: " + properties);
        System.err.println("body: " + new String(body));
    }
}

而consumer只需要修改

//5 创建消费者
QueueingConsumer queueingConsumer = new QueueingConsumer(channel);            //去掉这一步

//6 设置Channel
channel.basicConsume("test002", true, new MyConsumer(channel));

结果：

-----------consume message----------
consumerTag: amq.ctag-YK7CnvWxTpm6hmuyUyqSkQ
envelope: Envelope(deliveryTag=1, redeliver=false, exchange=, routingKey=test002)
properties: #contentHeader<basic>(content-type=null, content-encoding=null, headers=null, delivery-mode=null, priority=null, correlation-id=null, reply-to=null, expiration=null, message-id=null, timestamp=null, type=null, user-id=null, app-id=null, cluster-id=null)
body: Hello RabbitMQ By MyConsumer!

二、Exchange

　　Exchange有四种方式Fanout、Direct、Topic、Headers，而我们上面的例子，并没有定义Exchange，RabbitMQ默认使用AMQP default，

要求routing key和queue name相同

　　本文只是介绍前三种，Headers几乎用不到

2.1、Fanout

fanout效率是最好的，不需要routing key，你可以随便设置都无所谓，只要consumer和producer的Exchange name相同

producer

public class Producer {

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setVirtualHost("/");
        factory.setHost("139.196.75.238");
        factory.setPort(5672);

        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        String exchangeName = "exchange_fanout";
        channel.basicPublish(exchangeName, "", null, "send message by fanout".getBytes());
    }
}

consumer

public class Consumer {

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setVirtualHost("/");
        factory.setHost("139.196.75.238");
        factory.setPort(5672);

        factory.setAutomaticRecoveryEnabled(true);
        factory.setNetworkRecoveryInterval(3000);

        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        String exchangeName = "exchange_fanout";
        String exchangeType = "fanout";
        String queueName = "queue_fanout";
        String routingKey = "";    //不设置路由键

        channel.exchangeDeclare(exchangeName, exchangeType, true, false, false, null);
        channel.queueDeclare(queueName, true, false, false, null);
        channel.queueBind(queueName, exchangeName, routingKey);

        channel.basicConsume(queueName, true, new MyConsumer(channel));
    }
}

结果：

-----------consume message----------
consumerTag: amq.ctag-rXw7SbaR5aWVMQxZY6SfEA
envelope: Envelope(deliveryTag=1, redeliver=false, exchange=exchange_fanout, routingKey=)
properties: #contentHeader<basic>(content-type=null, content-encoding=null, headers=null, delivery-mode=null, priority=null, correlation-id=null, reply-to=null, expiration=null, message-id=null, timestamp=null, type=null, user-id=null, app-id=null, cluster-id=null)
body: send message by fanout

我们声明queue和exchange之后，要先观察exchange和queue对应关系

点击exchange name，进去查看是否binding成功，如果成功如下图

注意点：

　　1、fanout模式下不是直接操作Queue，而是把消息发送给Exchange，由Exchange把消息分发给与之绑定的Queue，也就是广播模式

　　2、Queue必须和Exchange进行绑定

　　3、每个Consumer的Queue name不能相同，个人测试下，相同的Queue name，只能有一个Consumer收到消息

2.2、Direct

　　完全把代码贴出来太浪费篇幅了，而且毫无意思，后面只说一下区别，顺便说一下，对于queue和exchange的declare无论放到producer还是

Consumer都可以的，个人习惯Consumer，而且二者启动顺序没有要求，因为RabbitMQ的消息具有堆积功能

Producer：

 String exchangeName = "exchange_direct";
 String routingKey = "key.direct";

 channel.basicPublish(exchangeName, routingKey, null, "send message by direct".getBytes());

Consumer：

String exchangeName = "exchange_direct";
String exchangeType = "direct";
String queueName = "queue_direct";
String routingKey = "key.direct";

channel.exchangeDeclare(exchangeName, exchangeType, true, false, false, null);
channel.queueDeclare(queueName, true, false, false, null);
channel.queueBind(queueName, exchangeName, routingKey);

channel.basicConsume(queueName, true, new MyConsumer(channel));

结果：

-----------consume message----------
consumerTag: amq.ctag-6UeNiGs1K-gMWbwvVn8F5A
envelope: Envelope(deliveryTag=1, redeliver=false, exchange=exchange_direct, routingKey=key.direct)
properties: #contentHeader<basic>(content-type=null, content-encoding=null, headers=null, delivery-mode=null, priority=null, correlation-id=null, reply-to=null, expiration=null, message-id=null, timestamp=null, type=null, user-id=null, app-id=null, cluster-id=null)
body: send message by direct

说明：

Direct要求routingKey完全一致

2.3、 topic

Producer：

String exchangeName = "exchange_topic";
String routingKey1 = "user.save";
String routingKey2 = "user.update";
String routingKey3 = "user.delete.abc";
//5 发送

String msg = "Send Message By topic";
channel.basicPublish(exchangeName, routingKey1 , null , msg.getBytes());
channel.basicPublish(exchangeName, routingKey2 , null , msg.getBytes());
channel.basicPublish(exchangeName, routingKey3 , null , msg.getBytes());

Consumer：

String exchangeName = "exchange_topic";
String exchangeType = "topic";
String queueName = "queue_topic";
String routingKey = "user.*";

channel.exchangeDeclare(exchangeName, exchangeType, true, false, false, null);
channel.queueDeclare(queueName, true, false, false, null);
channel.queueBind(queueName, exchangeName, routingKey);

说明：

　　Topic支持通配符匹配，#匹配一个或多个单词，*匹配一个单词