java - 如何在HiveMQ中正确连接身份验证？

我正在尝试使用HiveMQ通过简单身份验证将客户端连接到服务器。在HiveMQ客户端上，我创建了一个客户端，并使用connectWith()指定我要使用简单身份验证进行连接。输入用户名和密码后，我得到一个MqttClientStateException，我在下面留下了它。我是否应该像在本教程中一样输入username和password来在服务器上手动存储/配置用户名和密码：

https://hivemq.github.io/hivemq-mqtt-client/docs/mqtt_operations/connect.html#authenticationauthorization。

码：

Mqtt5BlockingClient publisher = Mqtt5Client.builder()
    .identifier(UUID.randomUUID().toString()) // the unique identifier of the MQTT client. The ID is randomly generated between
    .serverHost("localhost")  // the host name or IP address of the MQTT server. Kept it localhost for testing. localhost is default if not specified.
    .serverPort(1883)  // specifies the port of the server
    .addConnectedListener(context -> ClientConnectionRetreiver.printConnected("Publisher1"))         // prints a string that the client is connected
    .addDisconnectedListener(context -> ClientConnectionRetreiver.printDisconnected("Publisher1"))  // prints a string that the client is disconnected
    .buildBlocking();  // creates the client builder
    publisher.connectWith() // connects the client
        .simpleAuth()
            .username("Username")
            .password("Password".getBytes())
            .applySimpleAuth();

例外：

Exception in thread "SubThread1" com.hivemq.client.mqtt.exceptions.MqttClientStateException: MQTT client is not connected.
at com.hivemq.client.internal.mqtt.MqttBlockingClient.subscribe(MqttBlockingClient.java:101)
at com.hivemq.client.internal.mqtt.message.subscribe.MqttSubscribeBuilder$Send.send(MqttSubscribeBuilder.java:184)
at com.main.SubThread.run(SubThread.java:83)
at java.base/java.lang.Thread.run(Thread.java:834)

最佳答案

您忘了发送连接消息

publisher.connectWith()
        .simpleAuth()
            .username("Username")
            .password("Password".getBytes())
            .applySimpleAuth()
        .send();

如果您确实要对客户端进行身份验证，则必须配置服务器。使用HiveMQ，您可以使用基于文件角色的访问控制扩展（https://www.hivemq.com/extension/file-rbac-extension/）进行简单的身份验证。