Strus2.5更新用户成功后视图自动跳转不成功

Question

public String updateStu(){         StudentService ss = new StudentServiceImpl();         int id = Integer.parseInt(request.getParameter("id"));         Student s = ss.getStudentById(id);          request.setAttribute("stu", s);             try {             request.getRequestDispatcher("/jsps/PrepareUpdate.jsp").forward(request, response);         } catch (ServletException e) {             e.printStackTrace();         } catch (IOException e) {             e.printStackTrace();         }                  String name = request.getParameter("name");         int age = Integer.parseInt(request.getParameter("age"));         Student s1 = new Student(id,name,age);         ss.updateStudent(s1);         try {             response.sendRedirect("../getAll_stu.do");                      } catch (IOException e) {             // TODO 自动生成的 catch 块             e.printStackTrace();         }                 return "update";             }异常显示：Cannot call sendRedirect() after the response has been committed    响应后提交不能调用sendRedirect()