JAVA实现长连接 含心跳检测 Demo

                实现原理：

       长连接的维持，是要客户端程序，定时向服务端程序，发送一个维持连接包的。
       如果，长时间未发送维持连接包，服务端程序将断开连接。

客户端：
       Client通过持有Socket的对象，可以随时（使用sendObject方法）发送Massage Object(消息)给服务端。
       如果keepAliveDelay毫秒（程序中是2秒）内未发送任何数据，则自动发送一个KeepAlive Object(心跳)给服务端，用于维持连接。
       由于，我们向服务端，可以发送很多不同的消息对象，服务端也可以返回不同的对象。所以，对于返回对象的处理，要编写具体的ObjectAction实现类进行处理。通过Client.addActionMap方法进行添加。这样，程序会回调处理。

服务端：
        由于客户端会定时（keepAliveDelay毫秒）发送维持连接的信息过来，所以，服务端要有一个检测机制。
        即当服务端receiveTimeDelay毫秒（程序中是3秒）内未接收任何数据，则自动断开与客户端的连接。
         ActionMapping的原理与客户端相似（相同）。

         通过添加相应的ObjectAction实现类，可以实现不同对象的响应、应答过程。

Demo:

package socket.keepalive.test;import java.io.Serializable;import java.text.SimpleDateFormat;import java.util.Date;/** *  * 维持连接的消息对象（心跳对象） */public class KeepAlive implements Serializable{ private static final long serialVersionUID = -2813120366138988480L; /* 覆盖该方法，仅用于测试使用。  * @see java.lang.Object#toString()  */ @Override public String toString() {  return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())+"\t维持连接包"; }}

 

package socket.keepalive.test;import java.io.IOException;import java.io.InputStream;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.net.Socket;import java.net.UnknownHostException;import java.util.Collections;import java.util.concurrent.ConcurrentHashMap;/** * C/S架构的客户端对象，持有该对象，可以随时向服务端发送消息。 * <p> * 创建时间：2010-7-18 上午12:17:25 * @author HouLei * @since 1.0 */public class Client { /**  * 处理服务端发回的对象，可实现该接口。  */ public static interface ObjectAction{  void doAction(Object obj,Client client); }  public static final class DefaultObjectAction implements ObjectAction{  public void doAction(Object obj,Client client) {   System.out.println("处理：\t"+obj.toString());  } }   public static void main(String[] args) throws UnknownHostException, IOException {  String serverIp = "127.0.0.1";  int port = 65432;  Client client = new Client(serverIp,port);  client.start(); }  private String serverIp; private int port; private Socket socket; private boolean running=false; //连接状态  private long lastSendTime; //最后一次发送数据的时间  //用于保存接收消息对象类型及该类型消息处理的对象 private ConcurrentHashMap<Class, ObjectAction> actionMapping = new ConcurrentHashMap<Class,ObjectAction>();  public Client(String serverIp, int port) {  this.serverIp=serverIp;  this.port=port; }  public void start() throws UnknownHostException, IOException {  if(running)return;  socket = new Socket(serverIp,port);  System.out.println("本地端口："+socket.getLocalPort());  lastSendTime=System.currentTimeMillis();  running=true;  new Thread(new KeepAliveWatchDog()).start();  //保持长连接的线程，每隔2秒项服务器发一个一个保持连接的心跳消息  new Thread(new ReceiveWatchDog()).start();    //接受消息的线程，处理消息 }  public void stop(){  if(running)running=false; }  /**  * 添加接收对象的处理对象。  * @param cls 待处理的对象，其所属的类。  * @param action 处理过程对象。  */ public void addActionMap(Class<Object> cls,ObjectAction action){  actionMapping.put(cls, action); } public void sendObject(Object obj) throws IOException {  ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());  oos.writeObject(obj);  System.out.println("发送：\t"+obj);  oos.flush(); }  class KeepAliveWatchDog implements Runnable{  long checkDelay = 10;  long keepAliveDelay = 2000;  public void run() {   while(running){    if(System.currentTimeMillis()-lastSendTime>keepAliveDelay){     try {      Client.this.sendObject(new KeepAlive());     } catch (IOException e) {      e.printStackTrace();      Client.this.stop();     }     lastSendTime = System.currentTimeMillis();    }else{     try {      Thread.sleep(checkDelay);     } catch (InterruptedException e) {      e.printStackTrace();      Client.this.stop();     }    }   }  } }  class ReceiveWatchDog implements Runnable{  public void run() {   while(running){    try {     InputStream in = socket.getInputStream();     if(in.available()>0){      ObjectInputStream ois = new ObjectInputStream(in);      Object obj = ois.readObject();      System.out.println("接收：\t"+obj);      ObjectAction oa = actionMapping.get(obj.getClass());      oa = oa==null?new DefaultObjectAction():oa;      oa.doAction(obj, Client.this);     }else{      Thread.sleep(10);     }    } catch (Exception e) {     e.printStackTrace();     Client.this.stop();    }    }  } } }

 

package socket.keepalive.test;import java.io.IOException;import java.io.InputStream;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.net.ServerSocket;import java.net.Socket;import java.util.concurrent.ConcurrentHashMap;/** * C/S架构的服务端对象。 * <p> * 创建时间：2010-7-18 上午12:17:37 * @author HouLei * @since 1.0 */public class Server { /**  * 要处理客户端发来的对象，并返回一个对象，可实现该接口。  */ public interface ObjectAction{  Object doAction(Object rev, Server server); }  public static final class DefaultObjectAction implements ObjectAction{  public Object doAction(Object rev,Server server) {   System.out.println("处理并返回："+rev);   return rev;  } }  public static void main(String[] args) {  int port = 65432;  Server server = new Server(port);  server.start(); }  private int port; private volatile boolean running=false; private long receiveTimeDelay=3000; private ConcurrentHashMap<Class, ObjectAction> actionMapping = new ConcurrentHashMap<Class,ObjectAction>(); private Thread connWatchDog;  public Server(int port) {  this.port = port; } public void start(){  if(running)return;  running=true;  connWatchDog = new Thread(new ConnWatchDog());  connWatchDog.start(); }  @SuppressWarnings("deprecation") public void stop(){  if(running)running=false;  if(connWatchDog!=null)connWatchDog.stop(); }  public void addActionMap(Class<Object> cls,ObjectAction action){  actionMapping.put(cls, action); }  class ConnWatchDog implements Runnable{  public void run(){   try {    ServerSocket ss = new ServerSocket(port,5);    while(running){     Socket s = ss.accept();     new Thread(new SocketAction(s)).start();    }   } catch (IOException e) {    e.printStackTrace();    Server.this.stop();   }     } }  class SocketAction implements Runnable{  Socket s;  boolean run=true;  long lastReceiveTime = System.currentTimeMillis();  public SocketAction(Socket s) {   this.s = s;  }  public void run() {   while(running && run){    if(System.currentTimeMillis()-lastReceiveTime>receiveTimeDelay){     overThis();    }else{     try {      InputStream in = s.getInputStream();      if(in.available()>0){       ObjectInputStream ois = new ObjectInputStream(in);       Object obj = ois.readObject();       lastReceiveTime = System.currentTimeMillis();       System.out.println("接收：\t"+obj);       ObjectAction oa = actionMapping.get(obj.getClass());       oa = oa==null?new DefaultObjectAction():oa;       Object out = oa.doAction(obj,Server.this);       if(out!=null){        ObjectOutputStream oos = new ObjectOutputStream(s.getOutputStream());        oos.writeObject(out);        oos.flush();       }      }else{       Thread.sleep(10);      }     } catch (Exception e) {      e.printStackTrace();      overThis();     }     }   }  }    private void overThis() {   if(run)run=false;   if(s!=null){    try {     s.close();    } catch (IOException e) {     e.printStackTrace();    }   }   System.out.println("关闭："+s.getRemoteSocketAddress());  }   } }