为了避免污染宿主系统环境，于是在虚拟机中搭建了一个linux环境并且安装了rabbitmq-server。然后在远程连接的时候一直连接失败。官网上面给的例子都是在本地使用系统默认的guest用户连接的。没有给出远程连接的例子，于是阅读文档发现：

    When the serverfirst starts running, and detects that its database is uninitialised or hasbeen deleted, it initialises a fresh database with the following resources:
 
    a virtual hostnamed /
    a user namedguest with a default password of guest, granted full access to the / virtualhost.

也就是刚刚安装好rabbitmq-server，系统会自动创建一个名为“/”的virtual host，同时也会创建一个用户名和密码都是guest的用户，并且应用"/ virtual host"的所有访问权限。因此在rabbitmq安装的机器上使用官网给出的例子：

public class Send {
        // 队列名称
        privatefinal static String QUEUE_NAME = "hello";
 
        publicstatic void main(String[] argv) throws java.io.IOException {
               /**
                * 创建连接连接到MabbitMQ
                */
               ConnectionFactoryfactory = new ConnectionFactory();
               // 设置MabbitMQ所在主机ip或者主机名
               factory.setHost("localhost");
              
               // 创建一个连接
               Connectionconnection = factory.newConnection();
               // 创建一个频道
               Channelchannel = connection.createChannel();
              
               // 指定一个队列
               channel.queueDeclare(QUEUE_NAME,false, false, false, null);
              
               // 发送的消息
               Stringmessage = "hello world!";
               // 往队列中发出一条消息
               channel.basicPublish("",QUEUE_NAME, null, message.getBytes());
               System.out.println("[x] Sent '" + message + "'");
              
               // 关闭频道和连接
               channel.close();
               connection.close();
        }
}

运行是没问题的。如果要切换到远程机器访问的话，单纯的修改factory.setHost("localhost")是不行的。因为guest用户只是被容许从localhost访问。官网文档描述如下：

   "guest" user can only connect via localhost
 
    By default, theguest user is prohibited from connecting to the broker remotely; it can onlyconnect over a > loopback interface (i.e. localhost). This applies both toAMQP and to any other protocols enabled via plugins. Any > other users youcreate will not (by default) be restricted in this way.
 
    This isconfigured via the loopback_users item in the configuration file.
 
    If you wish toallow the guest user to connect from a remote host, you should set theloopback_users configuration item to []. A complete rabbitmq.config which doesthis would look like:

默认情况下，使用下面的命令：

rabbitmqctl environment

会发现：

我现在不想使用默认的guest用户，我新建立了一个用户test，然后授予所有权限，使用下面的命令：

rabbitmqctl add_user test 123456
rabbitmqctl set_user_tags test administrator
rabbitmqctl set_permissions -p / test ".*"".*" ".*"

 

创建用户

为用户设置角色

为用户设置权限

这种方式设置的默认的“/”权限，还可以自己添加其它权限

rabbitmqctl add_vhost vhost_test

然后使用下面的代码远程访问

public class Send2 {
	// 队列名称
	private final static String QUEUE_NAME = "hello";

	public static void main(String[] argv) throws java.io.IOException {
		/**
		 * 创建连接连接到MabbitMQ
		 */
		ConnectionFactory factory = new ConnectionFactory();
		// 设置MabbitMQ所在主机ip或者主机名
		factory.setHost("localhost");
		factory.setPort(5672);
		factory.setUsername("test");
		factory.setPassword("123456");
		factory.setVirtualHost("vhost_test");
		
		// 创建一个连接
		Connection connection = factory.newConnection();
		// 创建一个频道
		Channel channel = connection.createChannel();
		
		// 指定一个队列
		channel.queueDeclare(QUEUE_NAME, false, false, false, null);
		
		// 发送的消息
		String message = "hello world!";
		// 往队列中发出一条消息
		channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
		System.out.println(" [x] Sent '" + message + "'");
		
		// 关闭频道和连接
		channel.close();
		connection.close();
	}
}

public class Recv2 {
	// 队列名称
	private final static String QUEUE_NAME = "hello";

	public static void main(String[] argv) throws java.io.IOException,
			ShutdownSignalException, ConsumerCancelledException,
			InterruptedException {
		
		// 打开连接和创建频道，与发送端一样
		ConnectionFactory factory = new ConnectionFactory();
		factory.setHost("localhost");
		factory.setPort(5672);
		factory.setUsername("test");
		factory.setPassword("123456");
		factory.setVirtualHost("vhost_test");
		
		Connection connection = factory.newConnection();
		Channel channel = connection.createChannel();
		
		// 声明队列，主要为了防止消息接收者先运行此程序，队列还不存在时创建队列。
		channel.queueDeclare(QUEUE_NAME, false, false, false, null);
		System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

		// 创建队列消费者
		QueueingConsumer consumer = new QueueingConsumer(channel);
		// 指定消费队列
		channel.basicConsume(QUEUE_NAME, true, consumer);
		
		while (true) {
			// nextDelivery是一个阻塞方法（内部实现其实是阻塞队列的take方法）
			QueueingConsumer.Delivery delivery = consumer.nextDelivery();
			String message = new String(delivery.getBody());
			System.out.println(" [x] Received '" + message + "'");
		}
	}
}

输出：

 [*] Waiting for messages. To exit press CTRL+C
 [x] Received 'hello world!'

这次连接成功，测试通过