通过JSP九大内置对象创作一个简易的抽奖程序

科技2022-07-10 90

DBUtil工具类

package org.work.util; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class DBUtil { static { try { // 加载jdbc驱动程序 Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); } catch (ClassNotFoundException e) { e.printStackTrace(); } } public static Connection getConn() { Connection conn = null; try { // 使用DriverManager建立数据库连接 conn = DriverManager.getConnection( "jdbc:sqlserver://127.0.0.1:1433;databaseName=consumer", "sa", "1"); } catch (SQLException e) { System.err.println("连接失败"); } return conn; } public static void getClose(PreparedStatement ps, ResultSet rs, Connection conn) { // 关闭资源 try { if (ps != null) { ps.close(); } if (rs != null) { rs.close(); } if (conn != null) { conn.close(); } } catch (SQLException e) { e.printStackTrace(); } } }

draw.jsp文件

<%@ 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 '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">  </head> <body> <% Integer score = (Integer) request.getAttribute("score"); String msg = ""; if (score != null) { switch (score) { case -1: msg = "喜提25遍"; break; case 0: msg = "喜提25遍"; break; case 1: msg = "喜提20遍"; break; case 2: msg = "喜提15遍"; break; case 3: msg = "喜提10遍"; break; case 4: msg = "喜提5遍"; break; case 5: msg = "玩耍"; break; } } %> <%=msg%><br /> <form action="new.jsp" method="post"> <input type="submit" value="抽奖"> </form> </body> </html>

new.jsp文件

<%@ 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 'new.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">  </head> <body> <% //从application内置对象中获取map HashMap<String, Integer> scoreMap = (HashMap<String, Integer>) application .getAttribute("scoreMap"); //如果application中没有map，新建一个map if (scoreMap == null) { scoreMap = new HashMap<String, Integer>(); } String ip = request.getRemoteAddr(); //从map中查找是否有数据，如果没有数据就代表第一次访问，如果有数据就代表已经访问过 Integer score = scoreMap.get(ip); if (score == null) { score = new Random().nextInt(7) - 1; scoreMap.put(ip, score); } //将上边操作过的map存入(更新)到application中 application.setAttribute("scoreMap", scoreMap); request.setAttribute("score", score); request.getRequestDispatcher("draw.jsp").forward(request, response); %> </body> </html>

login.jsp文件

<%@ 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%>"> <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">  <style type="text/css"> table { margin: 0 auto; } .login { margin: 0 auto; } </style> </head> <% String msg = (String) request.getAttribute("msg"); if (msg == null) msg = ""; %> <body> <form action="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="pwd"> </td> </tr> <tr> <td colspan="2"> <span style="color: red"><%=msg%></span> </td> </tr> <tr> <td colspan="2" class="login"> <input type="submit" value="登录"> </td> </tr> </table> </form> </body> </html>

LoginServlet.java文件

package org.work.test; import java.io.IOException; import java.io.PrintWriter; 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 org.work.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 { // 1.设置编码 request.setCharacterEncoding("utf-8"); // 2.获取参数 String userName = request.getParameter("userName"); String pwd = request.getParameter("pwd"); HttpSession session = request.getSession(); System.out.println(session.getId()); // 连接数据库查询是否存在这样一条数据如果存在跳到result.jsp String sql = "SELECT * FROM users WHERE user_name=? and pwd=?"; Connection conn = null; PreparedStatement ps = null; ResultSet rs = null; boolean isTrue = false; // 调用util包下的DBUtil.getConn();加载驱动并和数据库建立连接 conn = DBUtil.getConn(); try { // 准备一个sql语句 // 使用prepareStatement访问数据库 ps = conn.prepareStatement(sql); ps.setString(1, userName); ps.setString(2, pwd); // 使用ResultSet接收访问数据库的反馈结果 rs = ps.executeQuery(); if (rs.next()) { isTrue = true; } else { isTrue = false; } } catch (SQLException e) { e.printStackTrace(); } // 调用util包下的getClose();方法关闭资源 DBUtil.getClose(ps, rs, conn); // 3.输出 if (isTrue) { session.setAttribute("userName", userName); response.sendRedirect("result.jsp"); } else { request.setAttribute("msg", "帐户名或密码错误!"); request.getRequestDispatcher("login.jsp") .forward(request, response); } } }

result.jsp文件

<%@ 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 'index.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">  </head> <body> <% String userName = (String) session.getAttribute("userName"); if (userName == null || "".equals(userName)) { response.sendRedirect("login.jsp"); } else { System.out.println("jsp:" + session.getId()); 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>

最后页面的运行结果如下图: 抽奖页面抽奖成功登录页面登陆失败页面登陆成功页面

Processed: 0.009, SQL: 8