<dependency>
     <groupId>com.rabbitmq</groupId>
     <artifactId>amqp-client</artifactId>
     <version>5.4.2</version>
 </dependency>

Hello World

建立一對一簡單通訊

//生產者
public class Send {
    private final static String QUEUE_NAME = "hello world";

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.56.128");
        factory.setUsername("admin");
        factory.setPassword("123456");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        String message = "Hello world";
        //第一個引數 為"" 表示使用預設的Exchange
        channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
        System.out.println("[x] Sent '" + message + "'");
        channel.close();
        connection.close();
    }

}
 

//消費者
public class Recv {
    private static final String QUEUE_NAME = "hello world";

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.56.128");
        factory.setUsername("admin");
        factory.setPassword("123456");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
        Consumer consumer = new DefaultConsumer(channel) {
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties,
                                       byte[] body) throws IOException {
                String message = new String(body, "UTF-8");
                System.out.print(" [x] Received '" + message + "'");
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);



    }
}
 

Work Queues

建立一對多通訊，和上述例子一致，只是開了多個消費者執行緒。

//生產者
public class NewTask {
    private final static String QUEUE_NAME = "hello";

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.56.128");
        factory.setUsername("admin");
        factory.setPassword("123456");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME,false,false,false,null);
        String[] messages = new String[]{"First message.", "Second message..",
                "Third message...", "Fourth message....", "Fifth message....."};
        for(String message : messages){
            channel.basicPublish("",QUEUE_NAME,null,message.getBytes());
            System.out.println("[x] Sent " + message);
        }
        channel.close();
        connection.close();
    }

}
 

//消費者
public class Worker {
    private static final String QUEUE_NAME = "hello";

    private static void doWork(String task) throws InterruptedException{
        for(char ch : task.toCharArray()){
            if(ch == '.'){
                Thread.sleep(1000);
            }
        }
    }

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.56.128");
        factory.setUsername("admin");
        factory.setPassword("123456");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.queueDeclare(QUEUE_NAME,false,false,false,null);
        Consumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                super.handleDelivery(consumerTag, envelope, properties, body);
                String message = new String(body,"UTF-8");
                System.out.println(" [X] received " +message);
                try{
                    doWork(message);//模擬長時工作
                }catch (InterruptedException e){
                    e.printStackTrace();
                }finally {
                    System.out.println(" [x] done");
                }

            }
        };
        //公平分發，RabbitMQ同一時刻最多接收一條訊息，在一個worker完成之前不會在分訊息給它，會把訊息分給不那麼忙的worker
        int prefetchCount = 1;
        channel.basicQos(prefetchCount);
        //message acknowledged 訊息確認標識
        boolean autoAck = true;
        channel.basicConsume(QUEUE_NAME,autoAck,consumer);

    }

}

開啟多個worker消費者時，生產者的訊息會迴圈分發

NewTask

[x] Sent First message. [x] Sent Second message.. [x] Sent Third message... [x] Sent Fourth message.... [x] Sent Fifth message.....

worker-1

 [X] received First message.  [x] done  [X] received Third message...  [x] done  [X] received Fifth message.....  [x] done

worker-2

 [X] received Second message..  [x] done  [X] received Fourth message....  [x] done