我写的Java学生成绩管理系统源代码

我写的Java学生成绩管理系统源代码(14)                                 new FileWriter("data.txt")));
            //System.out.println("delete No"+deleteNumber);
            while( (s1 = in2.readLine())!=null)
            {
                out.println(s1);
            }
            out.close();
            }catch (NumberNotFoundException e)
            {
                isDelete = false;
                System.out.println(deleteNumber+" no found :(");   
            }
        }catch(IOException e){}
    }
    public long numberTokenizer(String s)
    throws IOException
    {
        StringTokenizer st =
            new StringTokenizer(s," ");
        return Integer.valueOf((st.nextToken())).longValue();
    }
    public void findData(long find)//查找数据
    throws IOException,NumberNotFoundException
    {
        isFind = true;