我如何使用用户名和密码 paho 客户端连接 Java mqtt 客户端

How can i connect a Java mqtt client with username and password paho client

此代码在 Android Studio 中有效,但我如何使用用户名和密码登录? 有人可以帮帮我吗

package com.example.mqtt;


import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;

public class MainActivity extends AppCompatActivity {

    MqttAndroidClient client;
    TextView subText;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        subText = (TextView)findViewById(R.id.subText);

        ///This here are the mqtt broker informations

        String clientId = MqttClient.generateClientId();
        client = new MqttAndroidClient(this.getApplicationContext(), "mqtt://0.0.2.2:1883",clientId);

        try {
            IMqttToken token = client.connect();
            token.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Toast.makeText(MainActivity.this,"connected!!",Toast.LENGTH_LONG).show();
                    setSubscription();

                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Toast.makeText(MainActivity.this,"connection failed!!",Toast.LENGTH_LONG).show();
                }
            });
        } catch (MqttException e) {
            e.printStackTrace();
        }

        client.setCallback(new MqttCallback() {
            @Override
            public void connectionLost(Throwable cause) {

            }

            @Override
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                subText.setText(new String(message.getPayload()));
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken token) {

            }
        });

    }

    public void published(View v){

        String topic = "event";
        String message = "the payload";
        try {
            client.publish(topic, message.getBytes(),0,false);
            Toast.makeText(this,"Published Message",Toast.LENGTH_SHORT).show();
        } catch ( MqttException e) {
            e.printStackTrace();
        }
    }

    private void setSubscription(){

        try{

            client.subscribe("event",0);


        }catch (MqttException e){
            e.printStackTrace();
        }
    }

    public void conn(View v){

        try {
            IMqttToken token = client.connect();
            token.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Toast.makeText(MainActivity.this,"connected!!",Toast.LENGTH_LONG).show();
                    setSubscription();

                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Toast.makeText(MainActivity.this,"connection failed!!",Toast.LENGTH_LONG).show();
                }
            });
        } catch (MqttException e) {
            e.printStackTrace();
        }

    }

    public void disconn(View v){

        try {
            IMqttToken token = client.disconnect();
            token.setActionCallback(new IMqttActionListener() {
                @Override
                public void onSuccess(IMqttToken asyncActionToken) {
                    Toast.makeText(MainActivity.this,"Disconnected!!",Toast.LENGTH_LONG).show();


                }

                @Override
                public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                    Toast.makeText(MainActivity.this,"Could not diconnect!!",Toast.LENGTH_LONG).show();
                }
            });
        } catch (MqttException e) {
            e.printStackTrace();
        }
    }

}

您需要在传递 MqttConnectOptions 对象时使用 client.connect(); 的版本

查看文档 here

String clientId = MqttClient.generateClientId();
client = new MqttAndroidClient(this.getApplicationContext(), "mqtt://0.0.2.2:1883",clientId);

MqttConnectOptions options = new MqttConnectOptions();
options.setUserName("foo");
options.setPassword("bar".toCharArray());

try {
    IMqttToken token = client.connect(options);
    ...