Java之通过反射机制选择servlet中的对应的方法

此方法用于在对Javaee开发中的通过对应的名称而选择servlet中的对应的方法

注：主要代码如下

protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        /**
         * 这是设置浏览器编码的问题
         */
        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 {
            /**
             * 根据反射机制选择servlet对应的方法
             */
            Method method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class,
                    HttpServletResponse.class);
            /**
             * 利用反射调用对应的方法
             */
            method.invoke(this, req,resp);
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("这里是登录的时候反射机制的地方出错了！");
            req.getRequestDispatcher("error.jsp").forward(req, resp);
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }

示例

注：在后面的jsp页面中提交form表单中的 action="<%=request.getContextPath() %>/saveTeacher.ado"可以直接通过反射机制调用servlet中的saveTeacher方法

public class AdministratorsServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        /**
         * 这是设置浏览器编码的问题
         */
        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 {
            /**
             * 根据反射机制选择servlet对应的方法
             */
            Method method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class,
                    HttpServletResponse.class);
            /**
             * 利用反射调用对应的方法
             */
            method.invoke(this, req,resp);
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("这里是登录的时候反射机制的地方出错了！");
            req.getRequestDispatcher("error.jsp").forward(req, resp);
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }

    /**
     * 基于对教师的基本操作
     */

    /**
     * 添加一个教师
     * @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("保存一个教师基本信息成功！");
                req.getRequestDispatcher("saveSuccess.jsp").forward(req, resp);
            }
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("添加一个教师对象基本信息的时候失败！");
            resp.sendRedirect("error.jsp");
        }

    }
}

一、首先在web.xml文件里面配置相关的信息如下

注： <url-pattern>*.ado</url-pattern>  中的*则代表所选的对应方法

<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>

二、在jsp页面中from表单提交的时候需要注意它提交的action里面的内容

注： <form action="<%=request.getContextPath() %>/saveTeacher.ado" method="get">

 <body style="height: 100%;width: 100%; background-image:url(lib/skr.jpg); background-size: cover;">
         <div style="height: 100px;width: 100%; text-align: center;">
             <h1>学生成绩管理系统</h1>
         </div>
         <div align="center">
                 <form action="<%=request.getContextPath() %>/saveTeacher.ado" method="get">
                     <%
                         Teachers_Login teacherLogin = (Teachers_Login) request.getAttribute("teacherLogin");
                     %>
                         <input type="hidden" name="teacherId" value="<%=teacherLogin.getTeacherId()%>">
                         <input type="hidden" name="teacherName" value="<%=teacherLogin.getTeacherName()%>">
                     <table>
                         <tr>
                             <th colspan="2" align="center">请填写教师的基本信息</th>
                         </tr>
                         <tr>
                             <td>职工号：</td>
                             <td><%=teacherLogin.getTeacherId()%></td>
                         </tr>
                         <tr>
                             <td>姓名：</td>
                             <td><%=teacherLogin.getTeacherName()%></td>
                         </tr>
                         <tr>
                             <td>性别：</td>
                             <td><input type="text" name="sex"></td>
                         </tr>
                         <tr>
                             <td>电话号码：</td>
                             <td><input type="text" name="phoneNo"></td>
                         </tr>
                         <tr>
                             <td>家庭住址：</td>
                             <td><input type="text" name="address"></td>
                         </tr>
                         <tr>
                             <td>出生日期：</td>
                             <td><input type="text" name="birthday"></td>
                         </tr>
                         <tr>
                             <td>工资：</td>
                             <td><input type="text" name="salary"></td>
                         </tr>
                         <tr>
                             <td colspan="2" style="text-align: center;"><input type="submit" value="确定"><input type="reset" value="重置"></td>
                         </tr>
                     </table>
                 </form>
                 <p style="text-align: center;"><a href="administratorsMain.jsp">返回首页</a></p>
         </div>
 </body>

总结：这样就可以在jsp页面提交的时候选择servlet里面的所对应的方法了，希望对您有所帮助，谢谢！！！！！