This method is used to select the corresponding method in the servlet by the corresponding name in Javaee development.
Note: The main code is as follows
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { /** * This is the problem of setting up browser encoding */ req.setCharacterEncoding("UTF-8"); resp.setContentType("text/html,charset=UTF-8"); String servletPath = req.getServletPath(); String methodName = servletPath.substring(1); methodName = methodName.substring(0, methodName.length()-4); System.out.println(methodName); try { /** * Selection of servlet corresponding method based on reflection mechanism */ Method method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class); /** * Call the corresponding method with reflection */ method.invoke(this, req,resp); } catch (Exception e) { e.printStackTrace(); System.out.println("Here's where the reflection mechanism went wrong when you logged in!"); req.getRequestDispatcher("error.jsp").forward(req, resp); } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); }
Example
Note: Submitting action="<%=request.getContextPath()%>/saveTeacher.ado" in the form form form on the subsequent jsp page can directly invoke the saveTeacher method in the servlet through the reflection mechanism.
public class AdministratorsServlet extends HttpServlet { private static final long serialVersionUID = 1L; @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { /** * This is the problem of setting up browser encoding */ req.setCharacterEncoding("UTF-8"); resp.setContentType("text/html,charset=UTF-8"); String servletPath = req.getServletPath(); String methodName = servletPath.substring(1); methodName = methodName.substring(0, methodName.length()-4); System.out.println(methodName); try { /** * Selection of servlet corresponding method based on reflection mechanism */ Method method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class, HttpServletResponse.class); /** * Call the corresponding method with reflection */ method.invoke(this, req,resp); } catch (Exception e) { e.printStackTrace(); System.out.println("Here's where the reflection mechanism went wrong when you logged in!"); req.getRequestDispatcher("error.jsp").forward(req, resp); } } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doGet(req, resp); } /** * Basic Operation for Teachers */ /** * Add a teacher * @param req * @param resp * @throws ServletException * @throws IOException */ private void saveTeacher(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { try { Teachers teacher = new Teachers(); teacher.setTeacherId(Integer.parseInt(req.getParameter("teacherId"))); teacher.setTeacherName(req.getParameter("teacherName")); teacher.setSex(req.getParameter("sex")); teacher.setPhoneNo(req.getParameter("phoneNo")); teacher.setAddress(req.getParameter("address")); teacher.setBirthday(new Date(new SimpleDateFormat("yyyy-MM-dd").parse(req.getParameter("birthday")).getTime())); teacher.setSalary(new BigDecimal(req.getParameter("salary"))); ITeachersService teacherService = new TeachersServiceImpl(); int rows = teacherService.save(teacher); if(rows>0) { System.out.println("Success in preserving a teacher's basic information!"); req.getRequestDispatcher("saveSuccess.jsp").forward(req, resp); } } catch (Exception e) { e.printStackTrace(); System.out.println("Failed to add basic information about a teacher object!"); resp.sendRedirect("error.jsp"); } } }
First, configure the relevant information in the web.xml file as follows
Note: * in <url-pattern>*.ado</url-pattern> represents the selected corresponding method
<servlet>
<servlet-name>AdministratorsServlet</servlet-name>
<servlet-class>cn.gbb.student_achievement_system.controller.AdministratorsServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AdministratorsServlet</servlet-name>
<url-pattern>*.ado</url-pattern>
</servlet-mapping>
2. When submitting from form in jsp page, we need to pay attention to the content of action it submits.
Note: <form action="<%=request.getContextPath()%>/saveTeacher.ado" method="get">
1 <body style="height: 100%;width: 100%; background-image:url(lib/skr.jpg); background-size: cover;"> 2 <div style="height: 100px;width: 100%; text-align: center;"> 3 <h1>Student Achievement Management System</h1> 4 </div> 5 <div align="center"> 6 <form action="<%=request.getContextPath() %>/saveTeacher.ado" method="get"> 7 <% 8 Teachers_Login teacherLogin = (Teachers_Login) request.getAttribute("teacherLogin"); 9 %> 10 <input type="hidden" name="teacherId" value="<%=teacherLogin.getTeacherId()%>"> 11 <input type="hidden" name="teacherName" value="<%=teacherLogin.getTeacherName()%>"> 12 <table> 13 <tr> 14 <th colspan="2" align="center">Please fill in the teacher's basic information.</th> 15 </tr> 16 <tr> 17 <td>Staff number:</td> 18 <td><%=teacherLogin.getTeacherId()%></td> 19 </tr> 20 <tr> 21 <td>Full name:</td> 22 <td><%=teacherLogin.getTeacherName()%></td> 23 </tr> 24 <tr> 25 <td>Gender:</td> 26 <td><input type="text" name="sex"></td> 27 </tr> 28 <tr> 29 <td>Telephone number?</td> 30 <td><input type="text" name="phoneNo"></td> 31 </tr> 32 <tr> 33 <td>Family address:</td> 34 <td><input type="text" name="address"></td> 35 </tr> 36 <tr> 37 <td>Date of birth:</td> 38 <td><input type="text" name="birthday"></td> 39 </tr> 40 <tr> 41 <td>Wages:</td> 42 <td><input type="text" name="salary"></td> 43 </tr> 44 <tr> 45 <td colspan="2" style="text-align: center;"><input type="submit" value="Determine"><input type="reset" value="Reset"></td> 46 </tr> 47 </table> 48 </form> 49 <p style="text-align: center;"><a href="administratorsMain.jsp">Back to home page</a></p> 50 </div> 51 </body>
Summary: In this way, you can select the corresponding method in the servlet when submitting the jsp page. I hope it will be helpful to you. Thank you!!!!