类:
ServerMQTT
ClientMQTT
PushCallback
注: 例子中需要修改的地方:
1、localhost: 修改为上节安装服务的ip地址;
2、1883:修改为上节安装服务的端口,在配置文件中可修改,默认是(1883);
ServerMQTT类:
[java] view plain copy
1. /**
2. * Created by Administrator on 18-2-10.
3. */
4.
5. import org.eclipse.paho.client.mqttv3.MqttClient;
6. import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
7. import org.eclipse.paho.client.mqttv3.MqttDeliveryToken;
8. import org.eclipse.paho.client.mqttv3.MqttException;
9. import org.eclipse.paho.client.mqttv3.MqttMessage;
10. import org.eclipse.paho.client.mqttv3.MqttPersistenceException;
11. import org.eclipse.paho.client.mqttv3.MqttTopic;
12. import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
13. /**
14. *
15. * Title:Server
16. * 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
17. * @author admin
18. * 2017年2月10日下午17:41:10
19. */
20. public class ServerMQTT {
21.
22. //tcp://MQTT安装的服务器地址:MQTT定义的端口号
23. public static final String HOST = "tcp://localhost:1883";
24. //定义一个主题
25. public static final String TOPIC = "topic11";
26. //定义MQTT的ID,可以在MQTT服务配置中指定
27. private static final String clientid = "server11";
28.
29. private MqttClient client;
30. private MqttTopic topic11;
31. private String userName = "mosquitto";
32. private String passWord = "";
33.
34. private MqttMessage message;
35.
36. /**
37. * 构造函数
38. * @throws MqttException
39. */
40. public ServerMQTT() throws MqttException {
41. // MemoryPersistence设置clientid的保存形式,默认为以内存保存
42. client = new MqttClient(HOST, clientid, new MemoryPersistence());
43. connect();
44. }
45.
46. /**
47. * 用来连接服务器
48. */
49. private void connect() {
50. MqttConnectOptions options = new MqttConnectOptions();
51. options.setCleanSession(false);
52. options.setUserName(userName);
53. options.setPassword(passWord.toCharArray());
54. // 设置超时时间
55. 10);
56. // 设置会话心跳时间
57. 20);
58. try {
59. client.setCallback(new PushCallback());
60. client.connect(options);
61.
62. topic11 = client.getTopic(TOPIC);
63. } catch (Exception e) {
64. e.printStackTrace();
65. }
66. }
67.
68. /**
69. *
70. * @param topic
71. * @param message
72. * @throws MqttPersistenceException
73. * @throws MqttException
74. */
75. public void publish(MqttTopic topic , MqttMessage message) throws MqttPersistenceException,
76. MqttException {
77. MqttDeliveryToken token = topic.publish(message);
78. token.waitForCompletion();
79. "message is published completely! "
80. + token.isComplete());
81. }
82.
83. /**
84. * 启动入口
85. * @param args
86. * @throws MqttException
87. */
88. public static void main(String[] args) throws MqttException {
89. ServerMQTT server = new ServerMQTT();
90.
91. server.message = new MqttMessage();
92. 1);
93. server.message.setRetained(true);
94. "hello,topic11".getBytes());
95. server.publish(server.topic11 , server.message);
96. "------ratained状态");
97. }
98. }
ClientMQTT类:
[java] view plain copy
1. /**
2. *
3. * Description:
4. * @author admin
5. * 2017年2月10日下午17:50:15
6. */
7.
8. import java.util.concurrent.ScheduledExecutorService;
9. import org.eclipse.paho.client.mqttv3.MqttClient;
10. import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
11. import org.eclipse.paho.client.mqttv3.MqttException;
12. import org.eclipse.paho.client.mqttv3.MqttTopic;
13. import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
14.
15. public class ClientMQTT {
16.
17. public static final String HOST = "tcp://localhost:1883";
18. public static final String TOPIC = "topic11";
19. private static final String clientid = "client11";
20. private MqttClient client;
21. private MqttConnectOptions options;
22. private String userName = "admin";
23. private String passWord = "password";
24.
25. private ScheduledExecutorService scheduler;
26.
27. private void start() {
28. try {
29. // 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
30. client = new MqttClient(HOST, clientid, new MemoryPersistence());
31. // MQTT的连接设置
32. options = new MqttConnectOptions();
33. // 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
34. options.setCleanSession(true);
35. // 设置连接的用户名
36. options.setUserName(userName);
37. // 设置连接的密码
38. options.setPassword(passWord.toCharArray());
39. // 设置超时时间 单位为秒
40. 10);
41. // 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
42. 20);
43. // 设置回调
44. client.setCallback(new PushCallback());
45. MqttTopic topic = client.getTopic(TOPIC);
46. //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
47. "close".getBytes(), 2, true);
48.
49. client.connect(options);
50. //订阅消息
51. int[] Qos = {1};
52. String[] topic1 = {TOPIC};
53. client.subscribe(topic1, Qos);
54.
55. } catch (Exception e) {
56. e.printStackTrace();
57. }
58. }
59.
60. public static void main(String[] args) throws MqttException {
61. ClientMQTT client = new ClientMQTT();
62. client.start();
63. }
64. }
PushCallback类:
[java] view plain copy
1. /**
2. *
3. * Description:
4. * @author admin
5. * 2017年2月10日下午18:04:07
6. */
7.
8. import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
9. import org.eclipse.paho.client.mqttv3.MqttCallback;
10. import org.eclipse.paho.client.mqttv3.MqttMessage;
11.
12. /**
13. * 发布消息的回调类
14. *
15. * 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。
16. * 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。
17. * 在回调中,将它用来标识已经启动了该回调的哪个实例。
18. * 必须在回调类中实现三个方法:
19. *
20. * public void messageArrived(MqttTopic topic, MqttMessage message)接收已经预订的发布。
21. *
22. * public void connectionLost(Throwable cause)在断开连接时调用。
23. *
24. * public void deliveryComplete(MqttDeliveryToken token))
25. * 接收到已经发布的 QoS 1 或 QoS 2 消息的传递令牌时调用。
26. * 由 MqttClient.connect 激活此回调。
27. *
28. */
29. public class PushCallback implements MqttCallback {
30.
31. public void connectionLost(Throwable cause) {
32. // 连接丢失后,一般在这里面进行重连
33. "连接断开,可以做重连");
34. }
35.
36. public void deliveryComplete(IMqttDeliveryToken token) {
37. "deliveryComplete---------"
38. }
39.
40. public void messageArrived(String topic, MqttMessage message) throws Exception {
41. // subscribe后得到的消息会执行到这里面
42. "接收消息主题 : "
43. "接收消息Qos : "
44. "接收消息内容 : " + new String(message.getPayload()));
45. }
46. }
server类启动的结果:
[html] view plain copy
1. deliveryComplete---------true
2. message is published completely! true
3. true------ratained状态
client类启动的结果:
[html] view plain copy
1. 接收消息主题 : topic11
2. 接收消息Qos : 1
3. 接收消息内容 : hello,topic11
jar包下载:
demo下载: