Session实现简单购物车
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2022-03-15 09:48:51
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主要用于对Session对象的使用，大致过程由创建到销毁，即购物车的加入商品和清除购物车等一系列动作。Image类实现动态验证码。
（源码可以直接使用，注意路径问题）
Image类实现验证码功能
package com.ayit.session;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Image extends HttpServlet {
/**
*使用response实现验证码
* -生成图片
* -生成随机的数字和字母
* -把数字和字母画到图片上
* -把图片显示到页面上
*/
Random r = new Random();
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//生成图片
BufferedImage image = new BufferedImage(200,50,BufferedImage.TYPE_3BYTE_BGR);
//设置背景颜色
Graphics2D g2d = (Graphics2D) image.getGraphics();
g2d.setColor(Color.white);
g2d.fillRect(0, 0, 200, 50);
//创建一个StringBuffer存储字符串
StringBuffer sb = new StringBuffer();
//生成随机数
String word="23456789abcdefghjkmnopqrstuvwxyz";
g2d.setColor(Color.red);
int x =50,y=30;
for (int i = 0; i < 4; i++) {
//设置字体的样式
Font font = randomFont();
g2d.setFont(font);
//返回字符串里面字符的下标
int len = r.nextInt(word.length());
//根据位置得到具体的字符
char ch = word.charAt(len);
sb.append(ch);
//旋转的效果rotate(弧度,x,y)
//+-30度旋转
int jiaodu = r.nextInt(60)-30;
double h = jiaodu*Math.PI/180;
g2d.rotate(h, x, y);//旋转
g2d.setColor(randomColor());
//把生成的字符画到图片上
g2d.drawString(ch+"", x, y);
//旋转之后在转回去
g2d.rotate(-h,x,y);
x+=25;
}
// 把验证码放到session里面
request.getSession().setAttribute("image1", sb.toString());
//增加三条干扰线
int x1,x2,y1,y2;
for(int i=1;i<4;i++)
{
x1 = r.nextInt(200);
x2 = r.nextInt(200);
y1 = r.nextInt(50);
y2 = r.nextInt(50);
g2d.setColor(randomColor());
//划线
g2d.drawLine(x1,y1,x2,y2);
}
OutputImage(response, image);
}
private void OutputImage(HttpServletResponse response, BufferedImage image)
throws IOException, FileNotFoundException {
//把图片显示到页面上
ImageIO.write(image,"jpg",response.getOutputStream());
// int mc = r.nextInt(800);
// ImageIO.write(image,"jpg",new FileOutputStream("D:/"+mc+".jpg"));
}
private Font randomFont () {
String[] fontNames = {"宋体", "黑体", "楷体","方正舒体","华文彩云","华文琥珀"};
int index = r.nextInt(fontNames.length);
String fontName = fontNames[index];
int style = r.nextInt(4);
int size = r.nextInt(5) + 24;
return new Font(fontName, style, size);
}
private Color randomColor () {
int red = r.nextInt(150);
int green = r.nextInt(150);
int blue = r.nextInt(150);
return new Color(red, green, blue);
}
/**
*
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
login.jsp实现看不清换一张功能
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Login.html</title>
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
</head>
<body>
<h1>登录页面</h1>
<h2>${msg12}</h2>
<form action="/day10/Login" method="post">
Username:<input type="text" name="username"/><br/>
Password:<input type="password" name="pwd"/><br/>
image：<input type="text" name="image"/><br/>
<img id ="img1" alt="code" src="/day10/Image"/><br/>
<a href="javascript:void(0)" onclick="loadCode()">看不清，换一张</a>
<input type="submit" value="登录"/>
</form>
</body>
<script type="text/javascript">
function loadCode(){
//实现看不清换一张
var img1 = document.getElementById("img1");
//向src重新设置地址
img1.src = "/day10/Image?"+new Date().getTime();
}
</script>
</html>
Login类实现验证码判断功能，学过数据库以后，实现用户名和密码的验证
package com.ayit.session;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Login extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 得到输入的验证码
request.setCharacterEncoding("utf-8");
String imageText = request.getParameter("image");
// 得到图片的验证码
String imageCode = (String) request.getSession().getAttribute("image1");
if (!imageText.equals(imageCode)) {
// 设置一个值request
request.setAttribute("msg12", "验证码错误");
// 转发到登录页面
request.getRequestDispatcher("/session/login.jsp").forward(request,
response);
return;
} else {
request.getRequestDispatcher("/session/product.jsp").forward(
request, response);
}
}
/**
*
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
登录成功后来到product.jsp页面
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="com.ayit.utils.MyCookieUtils"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'product.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<img alt="1" src="/day10/img/1.jpg" />
<a href="/day10/SessionDemo1?id=1" />手电
</a>
<img alt="2" src="/day10/img/2.jpg" />
<a href="/day10/SessionDemo1?id=2" />手机
</a>
<img alt="3" src="/day10/img/3.jpg" />
<a href="/day10/SessionDemo1?id=3" />电视
</a>
<img alt="4" src="/day10/img/4.jpg" />
<a href="/day10/SessionDemo1?id=4" />冰箱
</a>
</body>
</html>
SessionDemo1类实现加入购物车功能，该类主要体现了Session对象的用法
package com.ayit.session;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class SessionDemo1 extends HttpServlet {
/**
* 根据id得到商品名称
* 1、判断是否是第一次购物
* 2、如果是，创建购物车，把商品名称和数量放到购物车
* 3、如果不是
* -判断购物车是否存在相同的商品
* --存在，原来的商品数量+1，放到购物车
* --不存在，把名称和数量加到购物车
*
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//根据id得到商品名称
String id1 = request.getParameter("id");
int id = Integer.parseInt(id1);
String[] names = {"手电","手机","电视","冰箱"};
String name = names[id-1];
//判断是否是第一次购物
Map<String,Integer> map = (Map<String,Integer>)request.getSession().getAttribute("cart");
if(map==null)
{
map = new HashMap<String, Integer>();
map.put(name, 1);
}
else
{
//不是第一次，判断购物车是否有相同名称的商品
if(map.containsKey(name))
{
int num = map.get(name);
map.put(name, num+1);
}else
{
//直接放名称和数量
map.put(name, 1);
}
}
//把购物车放到session里面
request.getSession().setAttribute("cart", map);
//输出两个超链接，继续购物和去结算
response.setContentType("text/html;charset=utf-8");
response.getWriter().write("<a href='/day10/session/product.jsp'>继续购物</a><br/>");
response.getWriter().write("<a href='/day10/session/cart.jsp'>去结算</a>");
}
/**
*
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
cart.jsp结算页面的实现
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'cart.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<h1>结算页面</h1>
<a href="/day10/clear">清空购物车</a>
<%
Map<String,Integer> map =( Map<String,Integer>) request.getSession().getAttribute("cart");
if(map==null)
{
%>
<h2>没有任何购物信息</h2>
<%
}else
{
//有购物信息，显示名称和数量
Set<String> keys = map.keySet();
for(String key : keys)
{
int num = map.get(key);
%>
<h3>
名称：<%=key%>
, 数量：<%=num %></h3>
<%
}
}
%>
</body>
</html>
clear类最后实现的是清空购物车，主要用于销毁Session对象
package com.ayit.session;
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 clear extends HttpServlet {
/**
*清空购物车
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpSession session = request.getSession();
//销毁session
session.invalidate();
response.sendRedirect("/day10/session/cart.jsp");
}
/**
*
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}