我想要的效果是,在文本框每输入一个英文单词,回车后将英文和中文解释添加到文本框中.英文单词及其解释可事先定义在程序中.下面是我做的程序,请高手帮帮手,改一下使它达到我想要的效果...

import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class UseText extends Applet implements ActionListener
{
  TextArea ta;
  TextField tf;
  String cha;
  String a;
 String eng[]={"god","good","bad","fine"};
     String ch[]={"上天","好的","坏的","良好"};
  public void init()
  {
     ta=new TextArea(4,30);
    tf=new TextField(30);
    add(ta);
    add(tf);
   tf.addActionListener(this);
   tf.requestFocus();
  }
    public void actionPerformed(ActionEvent e)
     {
      
       if(e.getSource()==tf)
         {  cha=tf.getText();
             if(cha=="god"){a=ch[0];}
             if(cha=="good"){a=ch[1];}
             if(cha=="bat"){a=ch[2];}
              
                   ta.append(tf.getText() + " " + a);  

              tf.setText(" ");    
              repaint();
              
          }
              
     }
}