不个简单的聊天程序

Question

import java.net.*;import java.awt.*;import java.io.*;import java.awt.event.*;import javax.swing.*;public class Server extends JFrame implements ActionListener{  TextField tf=new TextField(23);  TextArea ta=new TextArea();  Button bt=new Button("out");  ServerSocket ss;  Socket sk;    void run(){  try{       add(tf);       add(ta);       add(bt);       setLayout(new FlowLayout());       bt.addActionListener(this);       setSize(300,300);       setDefaultCloseOperation(EXIT_ON_CLOSE);       setVisible(true);       ss=new ServerSocket(8700);
                         while(true){
          Socket sk=ss.accept();     BufferedReader br=new BufferedReader(new InputStreamReader(sk.getInputStream()));          String ch=br.readLine();     ta.append(ch);
       System.out.println(ch);    }   }       catch(IOException e){        e.printStackTrace(); }}public void actionPerformed(ActionEvent e){   if(e.getActionCommand()=="out")     {       String st=tf.getText();     try{       OutputStream os=sk.getOutputStream();       os.write(st.getBytes());
                      os.flush();     }     catch(IOException o){}     }   } public static void main(String [] ii){        new Server().run(); } }
class Client extends JFrame implements ActionListener{
         TextArea tf2=new TextArea();
         TextField ta2=new TextField(23);
         Button bt2=new Button("out");
         Socket se;
      void wap(){
        try{
             add(tf2);
             add(ta2);
             add(bt2);
             bt2.addActionListener(this);   
             setLayout(new FlowLayout());
             setSize(300,300);
             setDefaultCloseOperation(EXIT_ON_CLOSE);
             setVisible(true);
             se=new Socket(InetAddress.getByName("127.0.0.1"),8700);
      while(true){
        BufferedReader la=new BufferedReader(new InputStreamReader(se.getInputStream()));
                   String sn=la.readLine();
                  // tf2.append("\n");
                       tf2.append(sn); 
}
        }
             catch(IOException t){
                     t.printStackTrace();
}
         
}
      public void actionPerformed( ActionEvent e){
              if(e.getActionCommand()=="out"){
                     String st=ta2.getText();
                     try{
                      OutputStream ap=se.getOutputStream();
                         ap.write(st.getBytes());
                         ap.flush();
}
                     catch(IOException i){
                         i.printStackTrace();
}
}
}    
       public static void main(String args[]){
                    new Client().wap();
}  
}      为啥点“out”后没反应呢