Servlet 4 JSP EL Cookie Session 商品浏览记录案例 购物车案例
JSP
JSP三种脚本元素
EL表达式(获取域中的数据)
Cookie
记录最新访问时间，获得cookie中上次访问时间，显示浏览器页面上
商品浏览记录案例
Session
验证码登录案例
购物车案例
持久Session案例(Session的JSESSIONID保存到Cookie中)
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在做练习的时候:
有些字段是不能小写的,例如:JSESSIONID.
输出HTML标签时,<a>标签少打了个 ' 导致页面无显示内容,但源码中有内容
JSP
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <h1>Hello JSP</h1> <%=new java.util.Date().toLocaleString() %> </body> </html>
JSP三种脚本元素
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <h1>学习JSP三种脚本元素</h1> <!-- JSP 声明脚本, 会被翻译为 Servlet成员变量、方法 --> <%! int a = 10; class A { // 内部类 } %> <!-- JSP 脚本表达式 ,输出HTML源代码 , 不能以 ;结尾 --> <%="aaa"+"bbb" %> <%="<h1>Hello</h1>" %> <!-- JSP脚本代码中 嵌入任意java代码 --> <% for(int i =0 ;i <10 ;i++){ // 输出i 到浏览器 out.print(i); } %> </body> </html>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <% // 可以嵌入任意java代码， 由多个 % 共同组成一段java代码， 脚本片段可以断开 for(int i = 0;i < 10 ;i++){ %> <h1>两个脚本片段中间可以编写HTML代码</h1> <% } %> </body> </html>
EL表达式(获取域中的数据)
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <!-- ServletContext 允许将一个数据保存到ServletContext ,这个数据全局数据，可以被多个Servlet共享 --> <!-- HttpServletRequest 允许将一个数据 保存 request对象中，通过请求转发，将数据传递另一个Servlet --> <% // 将数据 保存ServletContext中 getServletContext().setAttribute("name","传智播客"); // 将数据 保存request中 request.setAttribute("address","北京"); %> <!-- 取出上面保存两个值，输出浏览器端 --> <%=getServletContext().getAttribute("name") %> <%=request.getAttribute("address") %> <!-- 通过EL表达式 取出 name和address的值 --> ${ applicationScope.name} ${requestScope.address } <hr/> <!-- 访问一个不存在的属性 --> 传统%方式 ： <%=request.getAttribute("city") %> <br/> EL方式： ${requestScope.city } <br/> </body> </html>
Cookie
记录最新访问时间，获得cookie中上次访问时间，显示浏览器页面上
package cn.itcast.cookie; import java.io.IOException; import java.util.Date; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 记录最新访问时间，获得cookie中上次访问时间，显示浏览器页面上 * * @author seawind * */ public class VisitServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 判断是否存在cookie 信息 Cookie[] cookies = request.getCookies(); // 获得所有cookie信息 // 在cookies 数组中查找指定名称cookie Cookie lastVisitCookie = findCookie(cookies, "lastvisit"); if (lastVisitCookie == null) { // 不存在上次访问时间 response.setContentType("text/html;charset=utf-8"); response.getWriter().println("欢迎第一次访问XXX网站！"); } else { // 存在上次访问时间 long lastvisittimes = Long.parseLong(lastVisitCookie.getValue()); // 假设保存时间是毫秒 response.setContentType("text/html;charset=utf-8"); response.getWriter().println( "您上次的访问时间是：" + new Date(lastvisittimes).toLocaleString()); } // 向客户端写回最新访问时间 Cookie newLastVisitCookie = new Cookie("lastvisit", System .currentTimeMillis() + ""); newLastVisitCookie.setMaxAge(60 * 60);// 保存cookie 1小时 newLastVisitCookie.setPath("/"); response.addCookie(newLastVisitCookie); } // Cookie格式========== Cookie: name=value,name=value,name=value // 客户端对于同一个网站会存在很多个cookie private Cookie findCookie(Cookie[] cookies, String name) { if (cookies == null) { // 不存在任何cookie return null; } else { // 存在cookie，查找指定cookie for (Cookie cookie : cookies) { if (cookie.getName().equals(name)) { // 找到了 return cookie; } } // 没有找到 return null; } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
商品浏览记录案例
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@page import="cn.itcast.utils.CookieUtils"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <!-- 商品列表 --> <h1>商品列表</h1> <a href="/day7/show?id=1">Java编程大全</a> <a href="/day7/show?id=2">MYSQL秘笈</a> <a href="/day7/show?id=3">设计模式入门</a> <a href="/day7/show?id=4">数据结构和算法</a> <a href="/day7/show?id=5">软件工程</a> <a href="/day7/show?id=6">面向对象程序设计</a> <!-- 浏览记录 --> <h1>浏览记录</h1> <h2><a href="/day7/clear">清空记录</a></h2> <% // 获得history对应商品编号 Cookie historyCookie = CookieUtils.findCookie(request.getCookies(),"history"); if(historyCookie == null){ // 没有浏览记录 out.println("<h2>无任何商品浏览记录！</h2>"); }else{ // 有浏览记录 String value = historyCookie.getValue(); String[] ids = value.split(","); String[] names = {"Java编程大全","MYSQL秘笈","设计模式入门","数据结构和算法","软件工程","面向对象程序设计"}; for(String id : ids){ out.println(names[Integer.parseInt(id)-1]+"<br/>"); } } %> </body> </html>
package cn.itcast.cookie; import java.io.IOException; 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 cn.itcast.utils.CookieUtils; /** * 查看商品信息，将浏览记录 保存到cookie 中 * * @author seawind * */ public class ShowProductServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 从请求参数中 获得商品 id String id = request.getParameter("id"); // 获得history 对应cookie信息 Cookie historyCookie = CookieUtils.findCookie(request.getCookies(), "history"); // 判断historyCookie是否存在 if (historyCookie == null) { // 不存在，这是浏览的第一个商品 Cookie cookie = new Cookie("history", id); cookie.setMaxAge(60 * 60 * 24 * 14);// 两个星期 cookie.setPath("/"); response.addCookie(cookie); } else { // 商品浏览记录已经存在 // 判断该商品是否已经在浏览记录中，如果在 String value = historyCookie.getValue(); String[] ids = value.split(","); if (!checkExist(ids, id)) { // 7,8 +,+ 3 Cookie cookie = new Cookie("history", value + "," + id); cookie.setMaxAge(60 * 60 * 24 * 14);// 两个星期 cookie.setPath("/"); response.addCookie(cookie); } } response.setContentType("text/html;charset=utf-8"); response.getWriter().println( "商品浏览成功！<a href='/day7/cookie/product.jsp'>返回 </a>"); } // 判断商品编号 是否已经存在 浏览记录中 private boolean checkExist(String[] ids, String id) { for (String eachId : ids) { if (eachId.equals(id)) { // id已经存在 return true; } } return false; } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
package cn.itcast.cookie; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 删除 history 持久cookie * * @author seawind * */ public class ClearServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { Cookie cookie = new Cookie("history", ""); cookie.setMaxAge(0); cookie.setPath("/"); response.addCookie(cookie); response.sendRedirect("/day7/cookie/product.jsp"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
package cn.itcast.utils; import javax.servlet.http.Cookie; public class CookieUtils { // 根据name 查找指定cookie public static Cookie findCookie(Cookie[] cookies, String name) { if (cookies == null) { // 不存在任何cookie return null; } else { // 存在cookie，查找指定cookie for (Cookie cookie : cookies) { if (cookie.getName().equals(name)) { // 找到了 return cookie; } } // 没有找到 return null; } } }
Session
验证码登录案例
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <h1>登陆后 欢迎页面</h1> <% String username = (String)request.getSession().getAttribute("username"); if(username == null){ // 未登陆 out.println("您还未登陆，<a href='/day7/session/login.jsp'>去登陆</a>"); }else{ // 已经登陆 out.println("欢迎您，"+username); } %> </body> </html>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> <script type="text/javascript"> function change(){ document.getElementById("myimg").src = "/day7/checkimg?"+new Date().getTime(); } </script> </head> <body> <h1>登陆页面</h1> <h2 style="color:red;">${requestScope.msg }</h2> <form action="/day7/login" method="post"> <table> <tr> <td>用户名</td> <td><input type="text" name="username" /></td> </tr> <tr> <td>密码</td> <td><input type="password" name="password"/> </td> </tr> <tr> <td>验证码</td> <td><input type="text" name="checkcode" /> <img src="/day7/checkimg" onclick="change();" id="myimg" style="cursor: pointer;"/></td> </tr> <tr> <td colspan="2"><input type="submit" value="登陆" /></td> </tr> </table> </form> </body> </html>
package cn.itcast.session; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 进行登陆操作 * * @author seawind * */ public class LoginServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 获得用户名、密码和 验证码 request.setCharacterEncoding("utf-8"); String username = request.getParameter("username"); String password = request.getParameter("password"); String checkcode = request.getParameter("checkcode"); // 判断验证码是否正确 String checkcode_session = (String) request.getSession().getAttribute( "checkcode_session"); request.getSession().removeAttribute("checkcode_session"); if (checkcode_session == null || !checkcode_session.equals(checkcode)) { // 验证码输入错误 // 重定向跳回 login.jsp 无法携带信息，转发可以 request.setAttribute("msg", "验证码输入错误！"); request.getRequestDispatcher("/session/login.jsp").forward(request, response); return; } // 判断用户名和密码是否正确 ，假设用户名和密码都是admin/admin if ("admin".equals(username) && "admin".equals(password)) { // 登陆成功 // 将登陆信息保存session request.getSession().setAttribute("username", username); response.sendRedirect("/day7/session/welcome.jsp"); } else { // 登陆失败 request.setAttribute("msg", "用户名或者密码错误！"); request.getRequestDispatcher("/session/login.jsp").forward(request, response); } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
package cn.itcast.session; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.image.BufferedImage; 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; /** * 生成验证码图片 * * @author seawind * */ public class CheckImgServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 禁止缓存 // response.setHeader("Cache-Control", "no-cache"); // response.setHeader("Pragma", "no-cache"); // response.setDateHeader("Expires", -1); int width = 120; int height = 30; // 步骤一 绘制一张内存中图片 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 步骤二 图片绘制背景颜色 ---通过绘图对象 Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔 // 绘制任何图形之前 都必须指定一个颜色 graphics.setColor(getRandColor(200, 250)); graphics.fillRect(0, 0, width, height); // 步骤三 绘制边框 graphics.setColor(Color.WHITE); graphics.drawRect(0, 0, width - 1, height - 1); // 步骤四 四个随机数字 Graphics2D graphics2d = (Graphics2D) graphics; // 设置输出字体 graphics2d.setFont(new Font("宋体", Font.BOLD, 18)); // String words = // "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890"; String words = "\u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6"; Random random = new Random();// 生成随机数 // 为了将验证码保存Session StringBuffer buffer = new StringBuffer(); // 定义x坐标 int x = 10; for (int i = 0; i < 4; i++) { // 随机颜色 graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random .nextInt(110), 20 + random.nextInt(110))); // 旋转 -30 --- 30度 int jiaodu = random.nextInt(60) - 30; // 换算弧度 double theta = jiaodu * Math.PI / 180; // 生成一个随机数字 int index = random.nextInt(words.length()); // 生成随机数 0 到 length - 1 // 获得字母数字 char c = words.charAt(index); // 将生成汉字 加入buffer buffer.append(c); // 将c 输出到图片 graphics2d.rotate(theta, x, 20); graphics2d.drawString(String.valueOf(c), x, 20); graphics2d.rotate(-theta, x, 20); x += 30; } // 将验证码内容保存session request.getSession().setAttribute("checkcode_session", buffer.toString()); // 步骤五 绘制干扰线 graphics.setColor(getRandColor(160, 200)); int x1; int x2; int y1; int y2; for (int i = 0; i < 30; i++) { x1 = random.nextInt(width); x2 = random.nextInt(12); y1 = random.nextInt(height); y2 = random.nextInt(12); graphics.drawLine(x1, y1, x1 + x2, x2 + y2); } // 将上面图片输出到浏览器 ImageIO graphics.dispose();// 释放资源 ImageIO.write(bufferedImage, "jpg", response.getOutputStream()); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } /** * 取其某一范围的color * * @param fc * int 范围参数1 * @param bc * int 范围参数2 * @return Color */ private Color getRandColor(int fc, int bc) { // 取其随机颜色 Random random = new Random(); if (fc > 255) { fc = 255; } if (bc > 255) { bc = 255; } int r = fc + random.nextInt(bc - fc); int g = fc + random.nextInt(bc - fc); int b = fc + random.nextInt(bc - fc); return new Color(r, g, b); } }
购物车案例
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <!-- 商品列表页面 --> <h1>商品列表</h1> <h2><a href="/day7/session/cart.jsp">查看购物车</a></h2> Java编程大全 <a href="/day7/buy?id=1">购买</a> <br/> MySQL秘笈 <a href="/day7/buy?id=2">购买</a> <br/> 设计模式入门 <a href="/day7/buy?id=3">购买</a> <br/> 软件工程模式 <a href="/day7/buy?id=4">购买</a> <br/> 敏捷开发 <a href="/day7/buy?id=5">购买</a> <br/> 项目管理精要 <a href="/day7/buy?id=6">购买</a> <br/> </body> </html>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@page import="java.util.Map"%> <%@page import="java.util.Set"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <!-- 显示Session中保存 购物车数据 --> <% Map<String,Integer> map = (Map<String,Integer>)request.getSession().getAttribute("cart"); if(map == null){ // 购物车对象不存在 out.println("<h2>购物车无任何商品信息！</h2>"); }else{ // 购物车对象已经存在 out.println("<h1>商品列表</h1>"); out.println("<a href='/day7/clearCart'>清空购物车</a><br/>"); Set<String> keySet = map.keySet(); for(String productName: keySet){ int number = map.get(productName);// 购买数量 out.println("商品名称： " + productName +", 购买数量：" + number + "<br/>"); } } %> </body> </html>
package cn.itcast.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; import javax.servlet.http.HttpSession; /** * 添加商品到购物车 * * @author seawind * */ public class BuyServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 获得购买商品 id String id = request.getParameter("id"); // 获得id 对应商品名称 String[] names = { "Java编程入门", "MySQL秘笈", "设计模式入门", "软件工程模式", "敏捷开发", "项目管理精要" }; String productName = names[Integer.parseInt(id) - 1]; // 判断Session中购物车是否存在 HttpSession session = request.getSession(); Map<String, Integer> cart = (Map<String, Integer>) session .getAttribute("cart"); if (cart == null) { // 购物车不存在 cart = new HashMap<String, Integer>(); } // 判断购买商品是否存在于购物车中，商品名称就是map的key if (cart.containsKey(productName)) { // 商品已经在购物车中 int number = cart.get(productName);// 取出原来数量 cart.put(productName, number + 1);// 数量+1 放回购物车 } else { // 商品不在购物车中 cart.put(productName, 1);// 保存商品到购物车，数量为1 } // 将购物车对象保存Session session.setAttribute("cart", cart); // 给用户提示 response.setContentType("text/html;charset=utf-8"); response.getWriter().println( "商品已经添加到购物车！<a href='/day7/session/product.jsp'>返回</a>"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
package cn.itcast.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; /** * 清空购物车 * * @author seawind * */ public class ClearCartServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 删除购物车 cart对象 HttpSession session = request.getSession(); // 删除购物车cart对象 session.removeAttribute("cart"); // 跳转cart.jsp response.sendRedirect("/day7/session/cart.jsp"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
持久Session案例(Session的JSESSIONID保存到Cookie中)
package cn.itcast.session; import java.io.IOException; 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; /** * 第一次访问 创建Session对象，将数据保存到Session中 * * @author seawind * */ public class SessionServlet1 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 第一次访问，创建新的Session对象 HttpSession session = request.getSession(); // 将jsessionid 写到持久cookie中 Cookie cookie = new Cookie("JSESSIONID", session.getId()); cookie.setMaxAge(60 * 60 * 24); cookie.setPath("/"); response.addCookie(cookie); // 保存数据到Session session.setAttribute("name", "冰箱"); // 生成链接 --- 使用URL重写 String url = "/day7/session2";// 拼jsessionid url = response.encodeURL(url); response.getWriter().println("<a href='" + url + "'>session2</a>"); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
package cn.itcast.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; /** * 从Session读取 已经保存信息 显示到浏览器上 * * @author seawind * */ public class SessionServlet2 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 获得Session对象，因为不是第一次访问，获得之前已经存在Session HttpSession session = request.getSession(); // 获得之前保存name数据 String name = (String) session.getAttribute("name"); // 显示浏览器上 response.setContentType("text/html;charset=utf-8"); response.getWriter().println("name:" + name); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <servlet-name>HelloServlet</servlet-name> <servlet-class>cn.itcast.servlet.HelloServlet</servlet-class> </servlet> <servlet> <servlet-name>VisitServlet</servlet-name> <servlet-class>cn.itcast.cookie.VisitServlet</servlet-class> </servlet> <servlet> <servlet-name>ShowProductServlet</servlet-name> <servlet-class>cn.itcast.cookie.ShowProductServlet</servlet-class> </servlet> <servlet> <servlet-name>ClearServlet</servlet-name> <servlet-class>cn.itcast.cookie.ClearServlet</servlet-class> </servlet> <servlet> <servlet-name>SessionServlet1</servlet-name> <servlet-class>cn.itcast.session.SessionServlet1</servlet-class> </servlet> <servlet> <servlet-name>SessionServlet2</servlet-name> <servlet-class>cn.itcast.session.SessionServlet2</servlet-class> </servlet> <servlet> <servlet-name>BuyServlet</servlet-name> <servlet-class>cn.itcast.session.BuyServlet</servlet-class> </servlet> <servlet> <servlet-name>ClearCartServlet</servlet-name> <servlet-class>cn.itcast.session.ClearCartServlet</servlet-class> </servlet> <servlet> <servlet-name>CheckImgServlet</servlet-name> <servlet-class>cn.itcast.session.CheckImgServlet</servlet-class> </servlet> <servlet> <servlet-name>LoginServlet</servlet-name> <servlet-class>cn.itcast.session.LoginServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>HelloServlet</servlet-name> <url-pattern>/hello</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>VisitServlet</servlet-name> <url-pattern>/visit</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>ShowProductServlet</servlet-name> <url-pattern>/show</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>ClearServlet</servlet-name> <url-pattern>/clear</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>SessionServlet1</servlet-name> <url-pattern>/session1</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>SessionServlet2</servlet-name> <url-pattern>/session2</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>BuyServlet</servlet-name> <url-pattern>/buy</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>ClearCartServlet</servlet-name> <url-pattern>/clearCart</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>CheckImgServlet</servlet-name> <url-pattern>/checkimg</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>LoginServlet</servlet-name> <url-pattern>/login</url-pattern> </servlet-mapping> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
