长连接和短连接的区别、长连接的实现

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长连接和短连接的区别及原理

长连接的实现

package com.zmkj.app.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） * @author sunminghao */ public class LongLinkKeepAlive implements Serializable { 
    /* 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 com.zmkj.app.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。 * @author sunminghao */ public class LongLinkServer { 
    / * 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, LongLinkServer server); } public static final class DefaultObjectAction implements ObjectAction{ 
    @Override public Object doAction(Object rev, LongLinkServer server) { 
    System.out.println("处理并返回："+rev); return rev; } } public static void main(String[] args) { 
    int port = 65432; LongLinkServer server = new LongLinkServer(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 LongLinkServer(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{ 
    @Override 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(); LongLinkServer.this.stop(); } } } class SocketAction implements Runnable{ 
    Socket s; boolean run=true; long lastReceiveTime = System.currentTimeMillis(); public SocketAction(Socket s) { 
    this.s = s; } @Override 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,LongLinkServer.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()); } } } 

package com.zmkj.app.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.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。 * @author sunminghao */ public class LongLinkClient { 
    / * 处理服务端发回的对象，可实现该接口。 */ public static interface ObjectAction{ 
    void doAction(Object obj,LongLinkClient client); } public static final class DefaultObjectAction implements ObjectAction{ 
    @Override public void doAction(Object obj, LongLinkClient 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; LongLinkClient client = new LongLinkClient(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 LongLinkClient(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; @Override public void run() { 
    while(running){ 
    if(System.currentTimeMillis()-lastSendTime>keepAliveDelay){ 
    try { 
    LongLinkClient.this.sendObject(new LongLinkKeepAlive()); } catch (IOException e) { 
    e.printStackTrace(); LongLinkClient.this.stop(); } lastSendTime = System.currentTimeMillis(); }else{ 
    try { 
    Thread.sleep(checkDelay); } catch (InterruptedException e) { 
    e.printStackTrace(); LongLinkClient.this.stop(); } } } } } class ReceiveWatchDog implements Runnable{ 
    @Override 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, LongLinkClient.this); }else{ 
    Thread.sleep(10); } } catch (Exception e) { 
    e.printStackTrace(); LongLinkClient.this.stop(); } } } } }