JavaWeb：一个Servelt多个请求

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(1);//此时格式“*.do"
        methodName=methodName.substring(0,methodName.length()-3);//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