java客户端登陆服务器用户名验证

import java.io.*; import java.net.*; /* *客户端 */ class client {  public static void main(String[] args) throws Exception  {   Socket s = new Socket("192.168.33.1",10008);//建立服务   BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));//读取键盘输入用户名   PrintWriter pw = new PrintWriter(s.getOutputStream(),true);//读到数据往服务端写   BufferedReader bufin =    new BufferedReader(new InputStreamReader(s.getInputStream()));//将客户端返回的数据读入   for(int x = 0;x < 3; x ++)//只登陆3次设定   {    String line = bufr.readLine();//读取用户名    pw.println(line);    if(line == null)//为空用户名终止     break;    pw.println(line);    String info = bufin.readLine();//读取服务端返回的数据    System.out.println("Server info:"+info);    if(info.contains("欢迎登陆"))//用户登录终止     break;   }   bufr.close();   s.close();  } } /* *服务端 */ class ServerThread implements Runnable {  private Socket s;  ServerThread(Socket s)  {   this.s = s;  }  public void run()  {   String ip = s.getInetAddress().getHostAddress();   System.out.println(ip+"...........connect");   try   {    for(int x = 0;x < 3;x ++)    {     BufferedReader bufin = new BufferedReader(new InputStreamReader(s.getInputStream()));//读取客户端发送的数据     String name = bufin.readLine();     if(name == null)      break;     BufferedReader bufr = new BufferedReader(new FileReader("user.txt"));//读取已存入用户账户，本来是读取数据库，这里方便就写了一个文本     PrintWriter out = new PrintWriter(s.getOutputStream(),true);//写入流，服务端写出     String line = null;     boolean flag = false;//判断标记     while((line = bufr.readLine())!= null)//读取数据库(Use.txt)中数据     {      if(line.equals(name))//如果数据库和读取用户名相同，则终止      {       flag = true;       break;      }     }     if(flag)      {       System.out.println(name+":已登录");       out.println(name+":欢迎登陆");       break;      }     else     {      System.out.println(name+":尝试登陆");      out.println(name+":用户名不存在");     }    }    s.close();   }   catch (Exception e)   {    throw new RuntimeException("验证失败");   }  } } class server {  public static void main(String[] args) throws Exception  {   ServerSocket ss = new ServerSocket(10008);//建立服务   while (true)   {    Socket s = ss.accept();//接收客户端传来数据    new Thread(new ServerThread(s)).start();//开启线程   }  } }