聊天小程序客户端不能向服务器端发信息如何解决? 400 报错

聊天小程序客户端不能向服务器端发信息如何解决? 400 报错

小程序客户端：

import java.awt.*;import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.net.*;
public class Client {
 public static void main(String [] agrs){
  new MyWindow();
 }
}

class MyWindow extends JFrame implements ActionListener,WindowListener{
 public static JTextField text1;
 public static JTextField text2;
 public static JTextArea text3;
 public static Socket [] client=new Socket[4];
 public static JRadioButton[]jRadio=new JRadioButton[4];
 public static ClientThread []thread=new ClientThread[4];
 MyWindow(){
  super("客户程序");
  for(int i=0;i<4;i++){
   jRadio[i]=new JRadioButton("对话者"+i);
   thread[i]=null;
  }
  jRadio[0].setSelected(true);
  text1=new JTextField();
  text2=new JTextField();
  text3=new JTextArea();
  this.setLayout(null);
  JScrollPane jsp=new JScrollPane(text3);
  jsp.setBounds(10,10,400,400);
  text1.setBounds(10,420,400,30);
  text2.setBounds(10,460,400,30);
  JPanel pan=new JPanel();
  ButtonGroup g=new ButtonGroup();
  for(int i=0;i<4;i++){
   g.add(jRadio[i]);
   pan.add(jRadio[i]);
  }
  pan.setBounds(10,500,400,30);
  this.add(jsp);this.add(text1);this.add(text2);this.add(pan);
  this.setSize(420,570);
  this.setLocation(300,200);
  this.setResizable(false);
  this.setVisible(true);
  text1.addActionListener(this);
  text2.addActionListener(this);
  this.addWindowListener(this);
 }
 @SuppressWarnings("deprecation")
 public void windowClosing(WindowEvent e){
  for(int i=0;i<4;i++){
   if(client[i]!=null){
    try{
     this.thread[i].socket.close();
     client[i].close();
    }catch(IOException e1){}
    
   }
  }
 }
 public void windowActivated(WindowEvent e){}
 public void windowClosed(WindowEvent e){
  for(int i=0;i<4;i++){
   if(client[i]!=null){
    try{
     this.thread[i].socket.close();
     client[i].close();
    }catch(IOException e1){}
    
   }
  }
 }
 public void windowDeactivated(WindowEvent e){}
 public void windowDeiconified(WindowEvent e){}
    public void windowIconified(WindowEvent e){}
    public void windowOpened(WindowEvent e){}
 public void actionPerformed(ActionEvent e){
  if(e.getSource()==text1){
   for(int i=0;i<4;i++){
    if(client[i]==null){
     try{
      client[i]=new Socket(text1.getText(),4441);
     }catch(IOException g){
      text3.append("链接出错！！！"+"\n");
     }
     thread[i]=new ClientThread(client[i],i);
     thread[i].start();
     jRadio[i].setText(text1.getText());
     break;
    }
   }
  }else if(e.getSource()==text2){
   for(int i=0;i<4;i++){
    if(jRadio[i].isSelected()==true){
     try{
      thread[i].out.writeUTF(text2.getText());
      text3.append(text2.getText()+"\n");
      if(text2.getText().equals("结束")){
       client[i].close();
       client[i]=null;
       thread[i].socket.close();
       jRadio[i].setText("对话者"+i);
      }
      text2.setText("");
     }catch(IOException g2){
      text3.append("读写出错！！！"+"\n");
     }
    
    }
   }
  }
 }
}

class ClientThread extends Thread{
 int i;
 String s;
 Socket socket;
 public DataInputStream in;
 public DataOutputStream out;
 ClientThread(Socket s1,int j){
  i=j;
  socket=s1;
  try{
   in=new DataInputStream(socket.getInputStream());
      out=new DataOutputStream(socket.getOutputStream());
  }catch(IOException g){
   MyWindow.text1.setText("读写出错！！！");
  }
 }
 public void run(){
  while(true){
   try{
    s=in.readUTF();
    if(s.equals("结束")){
     socket.close();
     MyWindow.client[i].close();
     MyWindow.client[i]=null;
     MyWindow.jRadio[i].setText("对话者"+i);
     break;
    }
    MyWindow.text3.append(s+"\n");
   }catch(IOException g1){}
  }
 }
}

小程序服务器端：

import java.io.*;
import java.net.*;
import java.awt.*;

import javax.swing.*;

import java.awt.event.*;
public class Server {
 public static void main(String[]args){
  try{
   new MyWindows();
  }catch(NullPointerException e2){}
 }
}

class MyWindows extends JFrame implements ActionListener,WindowListener{
 public static JTextField text1;
 public static JTextArea text2;
 public static JRadioButton [] radio=new JRadioButton[4];
 public static Socket [] socket=new Socket[4];
 ServerThread [] thread=new ServerThread[4];
 public static ServerSocket server;
 MyWindows(){
  super("服务器程序");
  String s1;
  text1=new JTextField();
  text2=new JTextArea();
  this.setLayout(null);
  JScrollPane jsp=new JScrollPane(text2);
  jsp.setBounds(10,10,400,400);
  text1.setBounds(10,420,400,30);
  JPanel pan=new JPanel();
  ButtonGroup g=new ButtonGroup();
  for(int i=0;i<4;i++){
   radio[i]=new JRadioButton("对话者"+i);
   g.add(radio[i]);
   pan.add(radio[i]);
  }
  radio[0].setSelected(true);
  pan.setBounds(10,455,400,30);
  this.add(jsp);this.add(text1);
  this.add(pan);
  this.setSize(420, 520);
  this.setLocation(300,200);
  this.setResizable(false);
  this.setVisible(true);
  text1.addActionListener(this);
  this.addWindowListener(this);
  while(true){
   try{
    server=new ServerSocket(4441);
   }catch(IOException g1){
    text2.append("读写出错aaaaa！！！"+"\n");
   }
   try{
    for(int i=0;i<4;i++){
     if(socket[i]==null){
      socket[i]=server.accept();
      thread[i]=new ServerThread(socket[i],i);
      radio[i].setText(socket[i].getInetAddress().getHostAddress());
     }  
    }
   }catch(IOException g1){
    text2.append("网络出错！！！"+"\n");
   }
  }
 }
 public void windowClosing(WindowEvent e){
  for(int i=0;i<4;i++){
   if(socket[i]!=null){
    try{
     thread[i].out.writeUTF("结束");
     this.thread[i].socket.close();
     socket[i].close();
    }catch(IOException e1){}
    
   }
  }
  try {
   server.close();
  } catch (IOException e1) {
  }catch(NullPointerException e2){}
  System.exit(1);
 }
 public void windowActivated(WindowEvent e){}
 public void windowClosed(WindowEvent e){
  for(int i=0;i<4;i++){
   if(socket[i]!=null){
    try{
     this.thread[i].socket.close();
     socket[i].close();
    }catch(IOException e1){}
    
   }
  }
 }
 public void windowDeactivated(WindowEvent e){}
 public void windowDeiconified(WindowEvent e){}
    public void windowIconified(WindowEvent e){}
    public void windowOpened(WindowEvent e){}
 public void actionPerformed(ActionEvent e){
  if(e.getSource()==text1){
   for(int i=0;i<4;i++){
    if(radio[i].isSelected()==true){
     try {
      thread[i].out.writeUTF(text1.getText());
      text2.append(text1.getText()+"\n");
      if(text1.getText().equals("结束")){
       thread[i].socket.close();
       socket[i].close();
       socket[i]=null;
       radio[i].setText("对话者"+i);
      }
      text1.setText("");
     } catch (IOException e1) {
      text2.append("读写出错bbbb！！！"+"\n");
     }
    }
   }
  }
 }
}

class ServerThread extends Thread{
 int i;
 public String s;
 public Socket socket;
 public DataInputStream in;
 public DataOutputStream out;
 ServerThread(Socket soc,int j){
  i=j;
  socket=soc;
  try{
   in=new DataInputStream(socket.getInputStream());
   out=new DataOutputStream(socket.getOutputStream()); 
  }catch(IOException g){}
 }
 public void run(){
  while(true){
   try{
    s=in.readUTF();
    if(s.equals("结束")){
     socket.close();
     MyWindows.socket[i].close();
     MyWindows.socket[i]=null;
     MyWindows.radio[i].setText("对话者"+i);
     break;
    }
    MyWindows.text2.append(s+"\n");
   }catch(IOException g1){
   }
  }
 }
}

怎样解决（请改代码）？