給出一個百度雲開放平臺的Java客戶端示例程式碼，進行了一點點修改

以上一篇寫的文章中的websocket客戶端為釋出者。訂閱者我們用百度的示例Java程式

訂閱者的客戶端程式碼如下：

package com.mymqtt.baidu;

import java.security.KeyStore;

import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;

import org.eclipse.paho.client.mqttv3.MqttClient;
import
 
 org.eclipse.paho.client.mqttv3.MqttConnectOptions;

public class Client {

    public static void main(String[] args) throws Exception {
        String endpoint = "ssl://gwcheng.mqtt.iot.gz.baidubce.com:1884";   //輸入建立endpoint返回的地址
        String username = "gwcheng/mything1";    //輸入建立thing返回的username
        String password = "H0aUPreSnca3NslTft+oHjwgZEMjZPOfNBgXnb2F+6o="
 
; //輸入建立principal返回的password
        String topic = "helloTopic"; //訂閱的訊息主題，本例是指訂閱helloTopic

        TrustManagerFactory tmf = TrustManagerFactory.getInstance("X509");
        tmf.init((KeyStore)null);
        TrustManager[] trustManagers = tmf.getTrustManagers();

        SSLContext ctx = SSLContext.getInstance("TLS"
 
);
        ctx.init(null, trustManagers, null);

        MqttConnectOptions options = new MqttConnectOptions();
        options.setCleanSession(true);
        options.setUserName(username);
        options.setPassword(password.toCharArray());
        options.setSocketFactory(ctx.getSocketFactory());

        MqttClient client = new MqttClient(endpoint, topic);
        client.connect(options);
        client.setCallback(new PushCallback());
        // 為了不讓程式退出，一直處於接收訊息階段。
        while(true){

            client.subscribe(topic,2);;
        }

        // client.disconnect();
    }
}

好了，執行我們的websocket和Java程式

參考文獻