JSP——cooike和session

需求：用cooike和session分别做模拟登陆（在第一个网页输入用户名，在后面的网页显示用户名）。

session:

MainServlet.java

package web;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class MainServlet extends HttpServlet {

	@Override
	protected void service(
			HttpServletRequest req, 
			HttpServletResponse res)
			throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		String path = req.getServletPath();
		if("/toLogin.do".equals(path)) {
			toLogin(req,res);
		} else if("/login.do".equals(path)) {
			login(req,res);
		}
	}

	private void toLogin(
			HttpServletRequest req, 
			HttpServletResponse res) throws ServletException, IOException {
		req.getRequestDispatcher("WEB-INF/login.jsp")
			.forward(req, res);
	}

	private void login(
			HttpServletRequest req, 
			HttpServletResponse res) throws ServletException, IOException {
		HttpSession hs = req.getSession();
		hs.setAttribute("userCode", req.getParameter("userCode"));
		req.getRequestDispatcher("WEB-INF/index.jsp")
			.forward(req, res);
	}

}

login.jsp

<%@page pageEncoding="utf-8"%>


	
		
		
	
	
		

			

				
用户名：
				
密码：
				

			
		
	

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>



  
       
    
  
  
    
欢迎！${userCode }。
  

cookie:

MainServlet.java

package web;

import java.io.IOException;
import java.net.URLEncoder;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class MainServlet extends HttpServlet {

	@Override
	protected void service(
			HttpServletRequest req, 
			HttpServletResponse res)
			throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		String path = req.getServletPath();
		if("/toLogin.do".equals(path)) {
			toLogin(req,res);
		} else if("/login.do".equals(path)) {
			login(req,res);
		}
	}

	private void toLogin(
			HttpServletRequest req, 
			HttpServletResponse res) throws ServletException, IOException {
		req.getRequestDispatcher("WEB-INF/login.jsp")
			.forward(req, res);
	}

	private void login(
			HttpServletRequest req, 
			HttpServletResponse res) throws ServletException, IOException {
		Cookie c = new Cookie("userCode",
				URLEncoder.encode(req.getParameter("userCode"),"utf-8"));
		res.addCookie(c);		//在response中添加cookie，以便将cookie于发送到客户端
								//（session则是直接在服务器端设置）
		req.getRequestDispatcher("WEB-INF/index.jsp")
			.forward(req, res);
	}

}

login.jsp与上面相同

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>



  
       
    
  
  
    
欢迎！${cookie.userCode.value }。