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">

 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>学生成绩管理系统</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">请填写教师的基本信息</th>
15                         </tr>
16                         <tr>
17                             <td>职工号：</td>
18                             <td><%=teacherlogin.getteacherid()%></td>
19                         </tr>
20                         <tr>
21                             <td>姓名：</td>
22                             <td><%=teacherlogin.getteachername()%></td>
23                         </tr>
24                         <tr>
25                             <td>性别：</td>
26                             <td><input type="text" name="sex"></td>
27                         </tr>
28                         <tr>
29                             <td>电话号码：</td>
30                             <td><input type="text" name="phoneno"></td>
31                         </tr>
32                         <tr>
33                             <td>家庭住址：</td>
34                             <td><input type="text" name="address"></td>
35                         </tr>
36                         <tr>
37                             <td>出生日期：</td>
38                             <td><input type="text" name="birthday"></td>
39                         </tr>
40                         <tr>
41                             <td>工资：</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="确定"><input type="reset" value="重置"></td>
46                         </tr>
47                     </table>
48                 </form>
49                 <p style="text-align: center;"><a href="administratorsmain.jsp">返回首页</a></p>
50         </div>
51 </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！！！！！