/**
   * 添加一个学生信息
   *
   * @return
   * @throws Exception
   */
  public String addS() throws Exception {
    init();
    if (pictureUpload() != null) {
      student.setImageUrl(pictureUpload());
    }

    personService.saveStudent(student);
    request.setAttribute("SUCCESS", "添加学生成功");
    return "addSuccess";
  }
  /**
   * 处理学生信息的修改
   *
   * @return
   * @throws Exception
   */
  public String updateSDeal() throws Exception {
    init();
    if (pictureUpload() != null) {
      student.setImageUrl(pictureUpload());
      if (oldPicturePath != null) { // 设置了新的图片就删除原来的图片
        File file = new File(oldPicturePath);
        if (file.exists()) {
          file.delete();
        }
      }
    }
    personService.updateStudent(student);
    response.getWriter().write("<script type='text/javascript'> alert('修改学生信息成功')</script>");
    response.flushBuffer();
    response.getWriter().close();

    return NONE;
  }
  /**
   * 对学生信息的修改,可以是学生本身或者管理员
   *
   * @return
   * @throws Exception
   */
  public String updateS() throws Exception {
    init();
    String studentId = request.getParameter("studentId"); // 从请求参数过来的是老师更改
    if (studentId == null) {
      studentId = request.getSession().getAttribute("USER_ID").toString(); // 从session获得的是学生更改的
    }
    Student student = personService.getStudent(studentId);

    String imageUrl = student.getImageUrl();
    if (imageUrl != null) {
      oldPicturePath = imageUrl;
      imageUrl = imageUrl.substring(imageUrl.lastIndexOf("\\") + 1);
      String relativeUrl = "File/images/" + imageUrl;
      student.setImageUrl(relativeUrl);
    }

    request.setAttribute("student", student);

    return "updateSSuccess";
  }