JavaWeb：一个Servelt多个请求

时间：2022-02-20 14:51:46

一个Servelt多个请求

基础模拟

方法一：使用switch方法

 一、方法介绍

  • 方法：switch
  • 优点：方法简单，明了
  • 缺点：维护麻烦，保密性不好

二、代码实现

1、servlet类

package servlet;

/**

 * 使用参数进行多个请求

 */

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

@WebServlet("/CustomerServelet")

public class CustomerServelet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String method=request.getParameter("method");

        switch (method){

            case "add":

                add(request,response);

                break;

            case "update":

                update(request,response);

                break;

            case "delet":

                delet1(request,response);

                break;

                default:

                    break;

        }

    }

　　//删除

    private void delete(HttpServletRequest request, HttpServletResponse response) {

        System.out.println("delete");

    }

　　//更新

    private void update(HttpServletRequest request, HttpServletResponse response) {

        System.out.println("update");

    }

　　//添加

    private void add(HttpServletRequest request, HttpServletResponse response) {

        System.out.println("add");

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        doPost(request,response);

    }

}

2、jsp测试文件

<body>

　　<a href="CustomerServelet?method=add">Add</a>

　　<a href="CustomerServelet?method=update">Update</a>

　　<a href="CustomerServelet?method=delete">Delete</a>

</body>

方法二：使用Java反射方法

 一、方法介绍

  • 方法：Java反射
  • 优点：保密性好，易于维护
  • 缺点：比较麻烦

二、代码实现

1、servlet类

package servlet;

import mvcdemo.CriteriaCustomer;

import mvcdemo.CustomerDAO;

import mvcentity.Customer;

import mvcimpl.CustomerDAOJdbcImpl;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.lang.reflect.Method;

import java.util.List;

@WebServlet("*.do")

//或者

//@WebServlet("*.do")//符合“*.do”的格式，则映射到里面。

public class CustomerServelet1 extends HttpServlet {

    private static final long serialVersionUID=1L;

    private CustomerDAO customerDAO=new CustomerDAOJdbcImpl();

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //得到请求路径,格式为“/add.do”

        String serveletPath=request.getServletPath();　　　　 //格式路径，获取方法名

        String methodName=serveletPath.substring();//此时格式“*.do"

        methodName=methodName.substring(,methodName.length()-);//此时格式"*"

　　　　　//利用反射获取methodName对应的方法

        try{

            Method method=getClass().getDeclaredMethod(methodName,HttpServletRequest.class,HttpServletResponse.class);

            method.invoke(this,request,response);

        }catch (Exception e){

            e.printStackTrace();

        }

    }

    //删除private void delete(HttpServletRequest request, HttpServletResponse response) throws  ServletException,IOException{

        System.out.println("delete");

    }

　　//更新

    private void update(HttpServletRequest request, HttpServletResponse response) throws  ServletException,IOException{

         System.out.println("update");

    }

    //增加private void add(HttpServletRequest request, HttpServletResponse response) throws  ServletException,IOException{

　　　　　　System.out.println("add");

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
　　　　doPost(request,response);

    }

}

2、jsp测试文件

<body>

    <a href="add.do">Add</a>

    <a href="update.do">Update</a>

    <a href="delete.do">Delete</a>

</body>

三、说明

当运行jsp文件，并且点击其超链接，可以在控制台中显示出，相应的数据说明成功

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