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!")

(编辑:aniston)