MQTT——java简单测试(二)

服务端代码:

 1 package bsit.mqtt.demo.one_way;
 2 
 3 import org.eclipse.paho.client.mqttv3.MqttClient;
 4 import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
 5 import org.eclipse.paho.client.mqttv3.MqttDeliveryToken;
 6 import org.eclipse.paho.client.mqttv3.MqttException;
 7 import org.eclipse.paho.client.mqttv3.MqttMessage;
 8 import org.eclipse.paho.client.mqttv3.MqttPersistenceException;
 9 import org.eclipse.paho.client.mqttv3.MqttTopic;
10 import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
11 /**
12  * 
13  * Title:Server
14  * Description: 服务器向多个客户端推送主题,即不同客户端可向服务器订阅相同主题
15  * @author chenrl
16  * 2016年1月6日下午3:29:28
17  */
18 public class Server {
19 
20     public static final String HOST = "tcp://192.168.1.3:61613";
21     public static final String TOPIC = "toclient/124";
22     public static final String TOPIC125 = "toclient/125";
23     private static final String clientid = "server";
24 
25     private MqttClient client;
26     private MqttTopic topic;
27     private MqttTopic topic125;
28     private String userName = "admin";
29     private String passWord = "password";
30 
31     private MqttMessage message;
32 
33     public Server() throws MqttException {
34         // MemoryPersistence设置clientid的保存形式,默认为以内存保存
35         client = new MqttClient(HOST, clientid, new MemoryPersistence());
36         connect();
37     }
38 
39     private void connect() {
40         MqttConnectOptions options = new MqttConnectOptions();
41         options.setCleanSession(false);
42         options.setUserName(userName);
43         options.setPassword(passWord.toCharArray());
44         // 设置超时时间
45         options.setConnectionTimeout(10);
46         // 设置会话心跳时间
47         options.setKeepAliveInterval(20);
48         try {
49             client.setCallback(new PushCallback());
50             client.connect(options);
51             topic = client.getTopic(TOPIC);
52             topic125 = client.getTopic(TOPIC125);
53         } catch (Exception e) {
54             e.printStackTrace();
55         }
56     }
57 
58     public void publish(MqttTopic topic , MqttMessage message) throws MqttPersistenceException,
59             MqttException {
60         MqttDeliveryToken token = topic.publish(message);
61         token.waitForCompletion();
62         System.out.println("message is published completely! "
63                 + token.isComplete());
64     }
65 
66     public static void main(String[] args) throws MqttException {
67         Server server = new Server();
68 
69         server.message = new MqttMessage();
70         server.message.setQos(2);
71         server.message.setRetained(true);
72         server.message.setPayload("给客户端124推送的信息".getBytes());
73         server.publish(server.topic , server.message);
74         
75         server.message = new MqttMessage();
76         server.message.setQos(2);
77         server.message.setRetained(true);
78         server.message.setPayload("给客户端125推送的信息".getBytes());
79         server.publish(server.topic125 , server.message);
80 
81         System.out.println(server.message.isRetained() + "------ratained状态");
82     }
83 }

客户端代码:

 1 package bsit.mqtt.demo.one_way;  
 2   
 3 import java.util.concurrent.Executors;  
 4 import java.util.concurrent.ScheduledExecutorService;  
 5 import java.util.concurrent.TimeUnit;  
 6 
 7 import org.eclipse.paho.client.mqttv3.MqttClient;  
 8 import org.eclipse.paho.client.mqttv3.MqttConnectOptions;  
 9 import org.eclipse.paho.client.mqttv3.MqttException;  
10 import org.eclipse.paho.client.mqttv3.MqttSecurityException;  
11 import org.eclipse.paho.client.mqttv3.MqttTopic;  
12 import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
13   
14 public class Client {  
15   
16     public static final String HOST = "tcp://192.168.1.3:61613";  
17     public static final String TOPIC = "toclient/124";  
18     private static final String clientid = "client124";  
19     private MqttClient client;  
20     private MqttConnectOptions options;  
21     private String userName = "admin";
22     private String passWord = "password";
23   
24     private ScheduledExecutorService scheduler;  
25   
26     private void start() {  
27         try {  
28             // host为主机名,clientid即连接MQTT的客户端ID,一般以唯一标识符表示,MemoryPersistence设置clientid的保存形式,默认为以内存保存  
29             client = new MqttClient(HOST, clientid, new MemoryPersistence());  
30             // MQTT的连接设置  
31             options = new MqttConnectOptions();  
32             // 设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录,这里设置为true表示每次连接到服务器都以新的身份连接  
33             options.setCleanSession(true);  
34             // 设置连接的用户名  
35             options.setUserName(userName);  
36             // 设置连接的密码  
37             options.setPassword(passWord.toCharArray());  
38             // 设置超时时间 单位为秒  
39             options.setConnectionTimeout(10);  
40             // 设置会话心跳时间 单位为秒 服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线,但这个方法并没有重连的机制  
41             options.setKeepAliveInterval(20);  
42             // 设置回调  
43             client.setCallback(new PushCallback());  
44             MqttTopic topic = client.getTopic(TOPIC);  
45             //setWill方法,如果项目中需要知道客户端是否掉线可以调用该方法。设置最终端口的通知消息    
46             options.setWill(topic, "close".getBytes(), 2, true);  
47               
48             client.connect(options);  
49             //订阅消息  
50             int[] Qos  = {1};  
51             String[] topic1 = {TOPIC};  
52             client.subscribe(topic1, Qos);  
53             
54         } catch (Exception e) {  
55             e.printStackTrace();  
56         }  
57     }  
58    
59     public static void main(String[] args) throws MqttException {     
60         Client client = new Client();  
61         client.start();  
62     }  
63 }  

MQTT订阅回调类:

 1 package bsit.mqtt.demo.one_way;  
 2   
 3 import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
 4 import org.eclipse.paho.client.mqttv3.MqttCallback;  
 5 import org.eclipse.paho.client.mqttv3.MqttMessage;  
 6   
 7 /**  
 8  * 发布消息的回调类  
 9  *   
10  * 必须实现MqttCallback的接口并实现对应的相关接口方法CallBack 类将实现 MqttCallBack。  
11  * 每个客户机标识都需要一个回调实例。在此示例中,构造函数传递客户机标识以另存为实例数据。
12  * 在回调中,将它用来标识已经启动了该回调的哪个实例。  
13  * 必须在回调类中实现三个方法:  
14  *   
15  *  public void messageArrived(MqttTopic topic, MqttMessage message)接收已经预订的发布。  
16  *   
17  *  public void connectionLost(Throwable cause)在断开连接时调用。  
18  *   
19  *  public void deliveryComplete(MqttDeliveryToken token))  
20  *  接收到已经发布的 QoS 1 或 QoS 2 消息的传递令牌时调用。  
21  *  由 MqttClient.connect 激活此回调。  
22  *   
23  */    
24 public class PushCallback implements MqttCallback {  
25   
26     public void connectionLost(Throwable cause) {  
27         // 连接丢失后,一般在这里面进行重连  
28         System.out.println("连接断开,可以做重连");  
29     }  
30     
31     public void deliveryComplete(IMqttDeliveryToken token) {
32         System.out.println("deliveryComplete---------" + token.isComplete());  
33     }
34 
35     public void messageArrived(String topic, MqttMessage message) throws Exception {
36         // subscribe后得到的消息会执行到这里面  
37         System.out.println("接收消息主题 : " + topic);  
38         System.out.println("接收消息Qos : " + message.getQos());  
39         System.out.println("接收消息内容 : " + new String(message.getPayload()));  
40     }  
41 }  

 运行服务端代码,可看到服务器会给客户端124/125各推送一条消息,

在运行124客户端代码,可看到124客户端接收的信息:

然后把客户端代码的Topic改为TOPIC = "toclient/125";clientid = "client125";再运行该段代码,可看到125客户端接收的信息:

多个客户端订阅同一主题,其clientid必不相同。客户端124/125订阅各自主题的内容,但是不同时间启动,都在启动后接收到各自信息,这体现出了服务器的推送功能。同样的,发送的主题信息,可以在服务器的topic可以看到,访问路径是:http://127.0.0.1:61680/

其实,如若服务端和客户端相互通信,即客户端可以订阅可以发布,服务端可以订阅也可以发布,则可不区分服务端客户端,两边代码几乎一样。类似,两个客户端都在订阅同一主题,这时由第三个客户端发布这一主题的请求,前两个客户端同样可以接受该主题的内容,这时三个客户端的代码几乎一样,只是前两个是订阅,后一个是发布。

以上是自己纯碎学习所得,可能有很多bug,望后来人多多批评指正。

posted @ 2016-01-07 14:23  那些年的草木灰  阅读(38214)  评论(12编辑  收藏  举报