用Java实现多线程服务器程序

public class ServerSocket { 
public ServerSocket(int port) 
throws IOException ； 
public Socket accept() throws IOException ； 
public InetAddress getInetAddress() ； 
public int getLocalPort() ； 
public void close() throws IOException ； 
public synchronized void setSoTimeout 
(int timeout) throws SocketException ； 
public synchronized int 
getSoTimeout() throws IOException ； 
} 

//类receiveServer 
import java.io.*; 
import java.util.*; 
import java.net.*; 
public class receiveServer{ 
final int RECEIVE_PORT=9090; 
//该服务器的端口号 
//receiveServer的构造器 
public receiveServer() { 
ServerSocket rServer=null; 
//ServerSocket的实例 
Socket request=null; //用户请求的套接字 
Thread receiveThread=null; 
try{ 
rServer=new ServerSocket(RECEIVE_PORT); 
//初始化ServerSocket 
System.out.println("Welcome to the server!"); 
System.out.println(new Date()); 
System.out.println("The server is ready!"); 
System.out.println("Port: "+RECEIVE_PORT); 
while(true){ //等待用户请求 
request=rServer.accept(); 
//接收客户机连接请求 
receiveThread=new serverThread(request); 
//生成serverThread的实例 
receiveThread.start(); 
//启动serverThread线程 
} 
}catch(IOException e){ 
System.out.println(e.getMessage());} 
} 
public static void main(String args[]){ 
new receiveServer(); 
} //end of main 
} //end of class 
//类serverThread 
import java.io.*; 
import java.net.*; 
class serverThread extends Thread { 
Socket clientRequest; 
//用户连接的通信套接字 
BufferedReader input; //输入流 
PrintWriter output; //输出流 
public serverThread(Socket s) 
{ //serverThread的构造器 
this.clientRequest=s; 
//接收receiveServer传来的套接字 
InputStreamReader reader; 
OutputStreamWriter writer; 
try{ //初始化输入、输出流 
reader=new InputStreamReader 
(clientRequest.getInputStream()); 
writer=new OutputStreamWriter 
(clientRequest.getOutputStream()); 
input=new BufferedReader(reader); 
output=new PrintWriter(writer,true); 
}catch(IOException e){ 
System.out.println(e.getMessage());} 
output.println("Welcome to the server!"); 
//客户机连接欢迎词 
output.println("Now is: 
"+new java.util.Date()+" "+ 
"Port:"+clientRequest.getLocalPort()); 
output.println("What can I do for you?"); 
} 
public void run(){ //线程的执行方法 
String command=null; //用户指令 
String str=null; 
boolean done=false; 
while(!done){ 
try{ 
str=input.readLine(); //接收客户机指令 
}catch(IOException e){ 
System.out.println(e.getMessage());} 
command=str.trim().toUpperCase(); 
if(str==null || command.equals("QUIT")) 
//命令quit结束本次连接 
done=true; 
else if(command.equals("HELP")){ 
//命令help查询本服务器可接受的命令 
output.println("query"); 
output.println("quit"); 
output.println("help"); 
} 
else if(command.startsWith("QUERY")) 
{ //命令query 
output.println("OK to query something!"); 
} 
//else if …….. //在此可加入服务器的其他指令 
else if(!command.startsWith("HELP") && 
!command.startsWith("QUIT") && 
!command.startsWith("QUERY")){ 
output.println("Command not Found! 
Please refer to the HELP!"); 
} 
}//end of while 
try{ 
clientRequest.close(); //关闭套接字 
}catch(IOException e){ 
System.out.println(e.getMessage()); 
} 
command=null; 
}//end of run