小编Roy*_*ers的帖子

我正在 Java 中使用 MqttAsyncClient。以下代码只是我使用它的一部分，当我尝试订阅任何主题时出现错误时，问题就出现了：

客户端未连接 (32104)

    private int connections;
    private String topic;

    private MqttAsyncClient client;
    private MqttConnectOptions connOpts;
    private MemoryPersistence persistence;

private void configureMqtt() 
    {
        try 
        {
            logger.info("Starting the Mqtt Configuration...");

            client = new MqttAsyncClient(conf.getServerURI(), conf.getClientID(), persistence);
            connOpts = new MqttConnectOptions();

            connOpts.setCleanSession(true);
            connOpts.setUserName(conf.getUserName());
            connOpts.setPassword(conf.getPassword().toCharArray());
            connOpts.setAutomaticReconnect(true);

            logger.info("The Mqtt protocol has been configured successfully!!!");
        } 
        catch (Exception e) 
        {
            logger.error("An error has happened during Mqtt configuration");
            logger.error(e);
        }
    }

public void startSub()
{
    try
    {
        logger.info("Conecting to: " + conf.getServerURI() + " …