客户端和服务端

http://blog.csdn.net/zhu_tianwei/article/details/42983689

2015

另外一个MQTT发布订阅客户端paho-mqtt-client或mqttv3采用回调的方式实现消息的接收，下面看一下实现：

1.消息接收回调类

[java] view plain copy

print ?

package cn.smartslim.mqtt.demo.paho;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.MqttTopic;
/**
* 发布消息的回调类
*
* 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。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。在回调中，将它用来标识已经启动了该回调的哪个实例。
* ?必须在回调类中实现三个方法：
*
* public void messageArrived(MqttTopic topic, MqttMessage message)
* 接收已经预订的发布。
*
* public void connectionLost(Throwable cause)
* 在断开连接时调用。
*
* public void deliveryComplete(MqttDeliveryToken token))
* 接收到已经发布的 QoS 1 或 QoS 2 消息的传递令牌时调用。
* ?由 MqttClient.connect 激活此回调。
*
*/
public class PushCallback implements MqttCallback {
public void connectionLost(Throwable cause) {
// 连接丢失后，一般在这里面进行重连
System.out.println("连接断开，可以做重连");
}
public void deliveryComplete(MqttDeliveryToken token) {
// publish后会执行到这里
System.out.println("deliveryComplete---------"+ token.isComplete());
}
public void messageArrived(MqttTopic topic, MqttMessage message) throws Exception {
// subscribe后得到的消息会执行到这里面
System.out.println("接收消息主题:"+topic.getName());
System.out.println("接收消息Qos:"+message.getQos());
System.out.println("接收消息内容:"+new String(message.getPayload()));
}
}

2.服务端发布消息

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print ?

package cn.smartslim.mqtt.demo.paho;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.MqttPersistenceException;
import org.eclipse.paho.client.mqttv3.MqttTopic;
import org.eclipse.paho.client.mqttv3.internal.MemoryPersistence;
public class Server {
public static final String HOST = "tcp://192.168.36.102:1883";
public static final String TOPIC = "tokudu/yzq124";
private static final String clientid ="server";
private MqttClient client;
private MqttTopic topic;
private String userName = "test";
private String passWord = "test";
private MqttMessage message;
public Server() throws MqttException {
//MemoryPersistence设置clientid的保存形式，默认为以内存保存
client = new MqttClient(HOST, clientid, new MemoryPersistence());
connect();
}
private void connect() {
MqttConnectOptions options = new MqttConnectOptions();
options.setCleanSession(false);
options.setUserName(userName);
options.setPassword(passWord.toCharArray());
// 设置超时时间
options.setConnectionTimeout(10);
// 设置会话心跳时间
options.setKeepAliveInterval(20);
try {
client.setCallback(new PushCallback());
client.connect(options);
topic = client.getTopic(TOPIC);
} catch (Exception e) {
e.printStackTrace();
}
}
public void publish(MqttMessage message) throws MqttPersistenceException, MqttException{
MqttDeliveryToken token = topic.publish(message);
token.waitForCompletion();
System.out.println(token.isComplete()+"========");
}
public static void main(String[] args) throws MqttException {
Server server = new Server();
server.message = new MqttMessage();
server.message.setQos(1);
server.message.setRetained(true);
server.message.setPayload("eeeeeaaaaaawwwwww---".getBytes());
server.publish(server.message);
System.out.println(server.message.isRetained()+"------ratained状态");
}
}

3.客户端接收消息

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print ?

package cn.smartslim.mqtt.demo.paho;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttSecurityException;
import org.eclipse.paho.client.mqttv3.MqttTopic;
import org.eclipse.paho.client.mqttv3.internal.MemoryPersistence;
public class Client {
public static final String HOST = "tcp://192.168.36.102:1883";
public static final String TOPIC = "tokudu/yzq124";
private static final String clientid = "client";
private MqttClient client;
private MqttConnectOptions options;
private String userName = "test";
private String passWord = "test";
private ScheduledExecutorService scheduler;
//重新链接
public void startReconnect() {
scheduler = Executors.newSingleThreadScheduledExecutor();
scheduler.scheduleAtFixedRate(new Runnable() {
public void run() {
if (!client.isConnected()) {
try {
client.connect(options);
} catch (MqttSecurityException e) {
e.printStackTrace();
} catch (MqttException e) {
e.printStackTrace();
}
}
}
}, 0 * 1000, 10 * 1000, TimeUnit.MILLISECONDS);
}
private void start() {
try {
// host为主机名，test为clientid即连接MQTT的客户端ID，一般以客户端唯一标识符表示，MemoryPersistence设置clientid的保存形式，默认为以内存保存
client = new MqttClient(HOST, clientid, new MemoryPersistence());
// MQTT的连接设置
options = new MqttConnectOptions();
// 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
options.setCleanSession(true);
// 设置连接的用户名
options.setUserName(userName);
// 设置连接的密码
options.setPassword(passWord.toCharArray());
// 设置超时时间单位为秒
options.setConnectionTimeout(10);
// 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
options.setKeepAliveInterval(20);
// 设置回调
client.setCallback(new PushCallback());
MqttTopic topic = client.getTopic(TOPIC);
//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
options.setWill(topic, "close".getBytes(), 0, true);
client.connect(options);
//订阅消息
int[] Qos = {1};
String[] topic1 = {TOPIC};
client.subscribe(topic1, Qos);
} catch (Exception e) {
e.printStackTrace();
}
}
public void disconnect() {
try {
client.disconnect();
} catch (MqttException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws MqttException {
Client client = new Client();
client.start();
}
}

Android手机客户端实现demo：

https://github.com/dobermai/android-mqtt-push

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