使用Java如何实现异常自定义

     class ChushulingException extends Exception  {    public ChushulingException(String msg)    {      super(msg);    }  }   class ChushufuException extends Exception  {    public ChushufuException(String msg)    {      super(msg);    }  }    class Numbertest   {    public int shang(int x,int y) throws ChushulingException,ChushufuException    {      if(y<0)      {        throw new ChushufuException("您输入的是"+y+",规定除数不能为负数!");//抛出异常      }      if(y==0)      {        throw new ChushulingException("您输入的是"+y+",除数不能为0!");      }      int m=x/y;      return m;    }  }  class Rt001  {    public static void main(String[]args)    {      Numbertest n=new Numbertest();      //捕获异常      try      {        System.out.println("商="+n.shang(1,-3));      }      catch(ChushulingException yc)      {        System.out.println(yc.getMessage());        yc.printStackTrace();      }      catch(ChushufuException yx)      {        System.out.println(yx.getMessage());        yx.printStackTrace();      }      catch(Exception y)      {       System.out.println(y.getMessage());        y.printStackTrace();      }    finally{ System.out.println("finally!");} ////finally不管发没发生异常都会被执行     }  }