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    3. JSP实现抽奖效果和Session通信

    JSP实现抽奖效果和Session通信

    科技2022-07-12  119

    目录

    JSP抽奖小程序Java代码info.jsp代码 页面代码draw.jsp代码 浏览效果 Session通信效果Java代码LoginServlet代码 页面代码login.jsp代码result.jsp代码 浏览效果

    JSP抽奖小程序

    Java代码

    info.jsp代码

    <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <%@page import="java.security.AllPermission"%> <% 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 'info.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> <% HashMap<String, Integer> scoreMap = (HashMap<String, Integer>)application.getAttribute("scoreMap"); if(scoreMap == null){ scoreMap = new HashMap<String, Integer>(); } String ip = request.getRemoteAddr(); Integer score = scoreMap.get(ip); if (score == null) { score = new Random().nextInt(7) - 1; scoreMap.put(ip, score); } System.out.println(ip + ":" + score); application.setAttribute("scoreMap",scoreMap); request.setAttribute("score", score); request.getRequestDispatcher("draw.jsp").forward(request, response); %> </body> </html>

    页面代码

    draw.jsp代码

    <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%> <%@page import="java.util.Map.Entry"%> <% 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 'draw.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"> --> <style type="text/css"> body { text-align: center; } .btn { width: 300px; height: 150px; font-size: 60px; background: red; color: white; } .head { font-size: 60px; color: red; } .bottom { font-size: 40px; color: blue; } </style> </head> <body> <% HashMap<String, Integer> scoreMap = (HashMap<String, Integer>) application .getAttribute("scoreMap"); Integer score = (Integer) request.getAttribute("score"); String ip = (String) request.getAttribute("ip"); String msg = ""; if (score != null) { switch (score) { case -1: msg = "恭喜你要请我吃六顿饭"; break; case 0: msg = "恭喜你要请我吃五顿饭"; break; case 1: msg = "恭喜你要请我吃四顿饭"; break; case 2: msg = "恭喜你要请我吃三顿饭"; break; case 3: msg = "恭喜你要请我吃两顿饭"; break; case 4: msg = "恭喜你要请我吃一顿饭"; break; case 5: msg = "恭喜你啊,运气真好，请我吃一个月饭"; break; } } %> <h1 class="head"> 点击开始抽奖 </h1> <form action="info.jsp" method="post"> <input class="btn" type="submit" value="抽奖" /> </form> <h1 class="bottom"><%=msg%><br /> </h1> </body> </html>

    浏览效果

    打开效果： 点击抽奖之后： 这样一个抽奖程序就完成了

    Session通信效果

    在抽奖程序的基础下在添加以下代码

    Java代码

    LoginServlet代码

    package top.xinsir.test; import java.io.IOException; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession; import top.xinsir.util.DBUtil; public class LoginServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 设置编码 request.setCharacterEncoding("utf-8"); // 获取参数 String userName = request.getParameter("userName"); String pwd = request.getParameter("pwd"); HttpSession session = request.getSession(); Connection conn = null; ResultSet rs = null; PreparedStatement ps = null; conn = DBUtil.getConn(); String sql = "SELECT * FROM users WHERE user_name=? AND pwd=?"; try { ps = conn.prepareStatement(sql); ps.setString(1, userName); ps.setString(2, pwd); rs = ps.executeQuery(); if (rs.next()) { session.setAttribute("userName", userName); response.sendRedirect("result.jsp"); } else { request.setAttribute("msg", "账户名或密码错误"); request.getRequestDispatcher("login.jsp").forward(request, response); } } catch (SQLException e) { e.printStackTrace(); } } }

    页面代码

    login.jsp代码

    登录页面

    <%@ 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 'login.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> <% String msg = (String) request.getAttribute("msg"); if(msg==null) msg=""; %> <form action="login" method="post"> 用户名: <input type="text" name="userName" /><br /> 密码: <input type="text" name="pwd" /> <span style="color:red"><%=msg %></span><br /> <input type="submit" value="登录" /> </form> </body> </html>

    result.jsp代码

    查看用户抽奖的页面，先用session判断是否有用户名，然后从登录页面获取账号密码登陆之后，在info.jsp页面获取ip和抽奖的等级写到result.jsp中

    <%@ 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 'result.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> <% String userName = (String) session.getAttribute("userName"); if (userName == null || "".equals(userName)) { response.sendRedirect("login.jsp"); } else { HashMap<String, Integer> scoreMap = (HashMap<String, Integer>) application .getAttribute("scoreMap"); // 遍历map if (scoreMap != null) { for (String s : scoreMap.keySet()) { String key = s; Integer score = scoreMap.get(key); out.println(key + ":" + score + "分<br />"); } } } %> </body> </html>

    浏览效果

    先在draw.jsp页面点击一次抽奖 然后在地址栏输入result.jsp，会跳转到login.jsp页面 随便输入数据库没有的用户名和密码 点击登录之后还是在login.jsp页面，但是密码后面会显示账户名或密码错误 输入数据库中存储有的用户名和密码 点击登录之后 这样就完成了！

    Processed: 0.010, SQL: 8