RabbitMQ客户端连接报错原因分析

RabbitMQ客户端连接失败，可能原因包括地址、端口填错、用户名或者密码填错、超过最大连接数。

• 连接地址不正确

  VPC内访问场景下，连接地址不正确时，报错如下：

  [root@ecs-heru RabbitMQ-Tutorial]# java -cp .:rabbitmq-tutorial.jar Send 192.168.125.110 5672 user *******
  Exception in thread "main" java.net.NoRouteToHostException: No route to host (Host unreachable)
  at java.net.PlainSocketImpl.socketConnect(Native Method)
  at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
  at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)

  公网访问场景下，连接地址不正确时，报错如下：

  [root@ecs-heru RabbitMQ-Tutorial]# java -cp .:rabbitmq-tutorial.jar Send 139.xxx.178 5672 user *******
  Exception in thread "main" java.net.SocketTimeoutException: connect timed out
  at java.net.PlainSocketImpl.socketConnect(Native Method)
  at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)

• 端口不正确

  VPC内访问场景下，端口不正确时，报错如下：

  [root@ecs-heru RabbitMQ-Tutorial]# java -cp .:rabbitmq-tutorial.jar Send 192.168.125.111 5673 user *******
  Exception in thread "main" java.net.ConnectException: Connection refused (Connection refused)
  at java.net.PlainSocketImpl.socketConnect(Native Method)
  at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
  at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)

  公网访问场景下，端口不正确时，报错如下：

  [root@ecs-heru RabbitMQ-Tutorial]# java -cp .:rabbitmq-tutorial.jar Send 139.xxx.179 5673 user *******
  Exception in thread "main" java.net.SocketTimeoutException: connect timed out
  at java.net.PlainSocketImpl.socketConnect(Native Method)
  at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
  at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)

• 用户名或密码错误

  [root@ecs-heru RabbitMQ-Tutorial]# java -cp .:rabbitmq-tutorial.jar Send 192.168.125.111 5672 user *******
  Exception in thread "main" com.rabbitmq.client.AuthenticationFailureException: ACCESS_REFUSED - Login was refused using authentication mechanism PLAIN. For details
   see the broker logfile.
  at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:351)
  at com.rabbitmq.client.impl.recovery.RecoveryAwareAMQConnectionFactory.newConnection(RecoveryAwareAMQConnectionFactory.java:64)

• 超过最大连接数