java异常处理的简单练习

class Teacher{  private Computer cmp;  public void shangKe()throws NoPlanException      /*声明异常*/  {    cmp=new Computer();    try    {      cmp.run();    }    catch(LanPingException e)               /*电脑捕获处理蓝屏的异常*/                       {      cmp.recst();    }    catch(MaoYanException e)                /*电脑捕获处理电脑冒烟的异常*/    {      throw new NoPlanException("上课无法继续,因为"+e.getMessage());    /*电脑无法处理这个异常，继续把这个异常抛给老师来处理*/       }        System.out.println("老师上课");                /*没有异常，老师就正常上课*/  }}class LanPingException extends Exception               /*自定义蓝屏异常*/{  LanPingException(String m)  {    super(m);  }}class MaoYanException extends Exception             /*自定义电脑冒烟异常*/{  MaoYanException(String m)  {    super(m);  }}class NoPlanException extends Exception             /*自定义老师处理异常*/{  NoPlanException(String m)  {    super(m);  }}class Computer{  private int state=3;           /*不同的异常状态选择*/    public void run()throws LanPingException,MaoYanException  {    if(state==2)                         {      throw new LanPingException("电脑蓝屏了");        /*符合条件就抛出异常对象*/    }    if(state==3)    {      throw new MaoYanException("电脑冒烟了");    }    System.out.println("电脑运行");  }      public void recst()  {    System.out.println("电脑重启");  }}class ExceptionText{  public static void main(String args[])  {    Teacher t=new Teacher();    try    {      t.shangKe();    }    catch(NoPlanException e)               /*老师捕获处理电脑冒烟异常*/       {      System.out.println(e.toString());    }      }}