import java.io.*;import java.net.*;import java.util.*;import java.sql.*;public class Computer_server {    public static void main(String args[])  {  ServerSocket server=null;Server_thread thread;      Socket you=null;    while(true)     { try{ server=new ServerSocket(4331);}      catch(IOException e1) {System.out.println("正在監聽");}       try{ you=server.accept();}      catch (IOException e)      {System.out.println("正在等待客戶");}      if(you!=null)       {new Server_thread(you).start();   }      else {continue;}    }  }}class Server_thread extends Thread{  Socket socket;Connection Con=null;Statement Stmt=null;   DataOutputStream out=null;DataInputStream  in=null;int n=0;   String s=null;    Server_thread(Socket t)       { socket=t;         try {in=new DataInputStream(socket.getInputStream());             out=new DataOutputStream(socket.getOutputStream());             }         catch (IOException e)         {}       }    public void run()          { while(true)    { double a[]=new double[3] ;int i=0;       try{s=in.readUTF(); StringTokenizer fenxi=new StringTokenizer(s," ,");           while(fenxi.hasMoreTokens())             { String temp=fenxi.nextToken();                try{a[i]=Double.valueOf(temp).doubleValue();i++;}                catch(NumberFormatException e){out.writeUTF("請輸入數字字符");                      }             }           double p=(a[0]+a[1]+a[2])/2.0;           out.writeUTF(" "+Math.sqrt(p*(p-a[0])*(p-a[1])*(p-a[2])));           sleep(2);              }       catch(InterruptedException e){}       catch (IOException e)           {System.out.println("客戶離開");Thread.currentThread().yield();break;          }     }   } }