本文内容主要为【cookie实现Servlet之间数据共享】的实现代码。关于Servlet之间数据共享的实现方案与cookie详细内容可参考文章【多个Servlet之间数据共享实现方案】。本文为《多个Servlet之间数据共享实现方案》中第二节的代码实现部分。建议阅读本文前先去阅读《多个Servlet之间数据共享实现方案》。 一、项目运行环境

本案例使用的编译器为idea。 1、Tomcat环境

index.html

    
    


    
        
用户会员卡充值
        

            

                

                    
用户名：
                    

                
                

                    
金额：
                    

                
                

                    

                    

                
            
        
    

orderFood.html

    
    



    
用户点餐
    

        

            

                
饺子-20元：
                

            
            

                
油条-10元：
                

            
            

                
米饭-15元：
                

            
            

                

                

            
        
    

OneServlet.java

package com.Etui.controller;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.net.cookieStore;

@WebServlet(name = "OneServlet", value = "/one")
public class OneServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 获取参数
        String userName = request.getParameter("userName");
        String money = request.getParameter("money");

        // 开卡，即将信息存入cookie
        cookie card1 = new cookie("userName", userName);
        cookie card2 = new cookie("money", money);
        response.addcookie(card1);
        response.addcookie(card2);

        // 请求转发“orderFood”页面
        request.getRequestDispatcher("/orderFood.html").forward(request, response);

        System.out.println(userName + "," + money);
    }

}

TwoServlet.java

package com.Etui.controller;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;

@WebServlet(name = "TwoServlet", value = "/two")
public class TwoServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String userName = null;
        String food = null;
        cookie[] cookies = null;
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = response.getWriter();
        // 食物定价
        int jiaoziPrice = 20;
        int youtiaoPrice = 10;
        int mifanPrice = 15;
        int money = 0;
        // 获取参数
        food = request.getParameter("food");

        // 获取cookie
        cookies = request.getcookies();

        for (cookie cookie : cookies) {
            String key = cookie.getName();
            String value = cookie.getValue();
            if("userName".equals(key)) {
                userName = value;
            } else if("money".equals(key)) {
                money = Integer.parseInt(value);
                if("饺子".equals(food)) {
                    if(jiaoziPrice <= money) {
                        cookie newcookie = new cookie("money", (money - jiaoziPrice) + "");
                        out.print("
点餐成功！当前余额为" + newcookie.getValue() + "元");
                        // 添加money的cookie，覆盖原来的cookie
                        response.addcookie(newcookie);
                    } else {
                        out.print("余额不足，请充值！");
                    }
                } else if ("油条".equals(food)) {
                    if(youtiaoPrice <= money) {
                        cookie newcookie = new cookie("money", (money - youtiaoPrice) + "");
                        out.print("
点餐成功！当前余额为" + newcookie.getValue()+ "元");
                        // 添加money的cookie，覆盖原来的cookie
                        response.addcookie(newcookie);
                    } else {
                        out.print("余额不足，请充值！");
                    }
                } else if ("米饭".equals(food)) {
                    if(mifanPrice <= money) {
                        cookie newcookie = new cookie("money", money - mifanPrice + "");
                        out.print("
点餐成功！当前余额为" + newcookie.getValue() + "元");
                        // 添加money的cookie，覆盖原来的cookie
                        response.addcookie(newcookie);
                    } else {
                        out.print("余额不足，请充值！");
                    }
                }
            }
        }


//        System.out.println("用户名" + userName + "的余额为");
    }
}