谁能帮我看看这个applet为什么不能正常运行？

Question

keyDown(Event evt,int key)这个方法从jdk1.1以后都被processKeyEvent(KeyEvent)取代了
所以你的
public boolean keyDown(Event e,int key){………………}应该修改为：
public void processKeyEvent(KeyEvent key) 
    {          switch(currentmode)
        {
            case READY :
                  { if(key.getKeyCode() == 's' || key.getKeyCode() =='S')
                    currentmode=GAMING;
                    break;
                  }
            case PAUSE :
                  { if(key.getKeyCode() == 'p' || key.getKeyCode() =='P')
                    currentmode=GAMING;
                    break;
                  }
            case OVER :
                  {currentmode = READY;   // °´ÈÎÒâ¼ü×¼±¸ÓÎÏ·
                   break;
                   }
            case GAMING :
                  { if(key.getKeyCode() == 'p' || key.getKeyCode() == 'P') currentmode = PAUSE;
                    if(key.getKeyCode() == 'r' || key.getKeyCode() == 'R') currentmode = READY;
                    if(key.getKeyCode() == Event.LEFT&&Gun>=10)Gun-=5;
                    if(key.getKeyCode() == Event.RIGHT&&Gun<=(10+getSize().width))Gun+=5;
                    if(key.getKeyCode() == Event.UP)
                    {                    }
                    if(key.getKeyCode() == Event.DOWN)
                    if(key.getKeyCode() =='f'||key.getKeyCode()=='F')
                     {
                      bullet[BUNUM-1][0]=Gun;
                      bullet[BUNUM-1][1]=800;
                      BUNUM++;
                      if(BUNUM>50)
                      BUNUM=0;
                      }
                     break;
                  }
        }
       
    }