JavaWeb16.7【Cookie&Session：案例-登录验证码】
1 <%-- 2 Created by IntelliJ IDEA. 3 User: yubaby 4 Date: 2021/7/3 5 Time: 12:32 6 To change this template use File | Settings | File Templates. 7 --%> 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 9 <html> 10 <head> 11 <title>Title</title> 12 13 <script> 14 window.onload = function () { 15 document.getElementById("img").onclick = function () { 16 var timeStamp = new Date().getTime(); 17 this.src = "/day16/checkCodeServlet?time=" + timeStamp; 18 //this即通过document.getElementById("img")获取到的对象 19 } 20 } 21 </script> 22 <style> 23 div{ 24 color: red; 25 } 26 </style> 27 </head> 28 <body> 29 30 <form action="/day16/LoginServlet" method="post"> 31 <table> 32 <tr> 33 <td>用户名</td> 34 <td><input type="text" name="username"></td> 35 </tr> 36 <tr> 37 <td>密码</td> 38 <td><input type="password" name="password"></td> 39 </tr> 40 <tr> 41 <td>验证码</td> 42 <td><input type="text" name="checkCode"></td> 43 </tr> 44 <tr> 45 <td colspan="2"><img id="img" src="/day16/checkCodeServlet"></td> 46 </tr> 47 <tr> 48 <td colspan="2"><input type="submit" value="登录"></td> 49 </tr> 50 </table> 51 </form> 52 53 <div><%=request.getAttribute("cc_error")==null ? "" : request.getAttribute("cc_error")%></div> 54 <div><%=request.getAttribute("login_error")==null ? "" : request.getAttribute("login_error")%></div> 55 </body> 56 </html>
1 <%-- 2 Created by IntelliJ IDEA. 3 User: yubaby 4 Date: 2021/7/3 5 Time: 13:28 6 To change this template use File | Settings | File Templates. 7 --%> 8 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 9 <html> 10 <head> 11 <title>Title</title> 12 </head> 13 <body> 14 <h1><%=request.getSession().getAttribute("user")%>,欢迎您</h1> 15 </body> 16 </html>
1 package com.haifei.servlet; 2 3 import javax.servlet.ServletException; 4 import javax.servlet.annotation.WebServlet; 5 import javax.servlet.http.HttpServlet; 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse; 8 import javax.servlet.http.HttpSession; 9 import java.io.IOException; 10 import java.util.Map; 11 12 /** 13 * session案例-登录验证码 14 */ 15 @WebServlet("/LoginServlet") 16 public class LoginServlet extends HttpServlet { 17 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 18 //1 设置request编码 19 request.setCharacterEncoding("utf-8"); 20 //2 获取参数集合 21 /*Map<String, String[]> parameterMap = request.getParameterMap(); 22 for (String key: parameterMap.keySet()) { 23 String[] value = parameterMap.get(key); 24 System.out.println(key + ":" + value); 25 }*/ 26 String username = request.getParameter("username"); 27 String password = request.getParameter("password"); 28 String checkCode = request.getParameter("checkCode"); 29 30 //3 判断用户输入的验证码是否正确 31 //======================================== 32 //获取checkCodeServlet生成的验证码 33 HttpSession session = request.getSession(); 34 // Object checkCodeTruth = session.getAttribute("checkCodeTruth"); 35 String checkCodeTruth = (String)session.getAttribute("checkCodeTruth"); //需要强转为字符串类型，不然equalsIgnoreCase报错 36 //用完之后立即删除session中存储的验证码，增强安全性(保证验证码的一次性使用) 37 session.removeAttribute("checkCodeTruth"); 38 //======================================== 39 if (checkCodeTruth!=null && checkCodeTruth.equalsIgnoreCase(checkCode)){ //忽略大小写比较字符串方法 40 //一致，用户输入验证码正确 41 42 //判断用户输入的用户名和密码是否正确 43 if ("zhangsan".equals(username) && "123".equals(password)){ //此处实际应该调用UserDao查询数据库数据 44 //登录成功 45 46 //存储用户信息 47 session.setAttribute("user", username); //此处实际应该传入查询出来的user对象 48 //重定向到success.jsp 49 response.sendRedirect(request.getContextPath() + "/success.jsp"); 50 }else { 51 //登录失败 52 53 //存储提示信息到request 54 request.setAttribute("login_error", "用户名或密码错误"); 55 //转发到登录页面 56 request.getRequestDispatcher("/login.jsp").forward(request, response); 57 } 58 59 }else { 60 //不一致，用户输入验证码不正确 61 62 //存储提示信息到request 63 request.setAttribute("cc_error", "验证码错误"); 64 //转发到登录页面 65 request.getRequestDispatcher("/login.jsp").forward(request, response); 66 } 67 68 } 69 70 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 71 this.doPost(request, response); 72 } 73 }
1 package com.haifei.servlet; 2 3 import javax.imageio.ImageIO; 4 import javax.servlet.ServletException; 5 import javax.servlet.annotation.WebServlet; 6 import javax.servlet.http.HttpServlet; 7 import javax.servlet.http.HttpServletRequest; 8 import javax.servlet.http.HttpServletResponse; 9 import javax.servlet.http.HttpSession; 10 import java.awt.*; 11 import java.awt.image.BufferedImage; 12 import java.io.IOException; 13 import java.util.Random; 14 15 /** 16 * Response对象案例-验证码 17 */ 18 @WebServlet("/checkCodeServlet") 19 public class CheckCodeServlet extends HttpServlet { 20 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 21 int width = 100; 22 int height = 50; 23 24 //1 创建对象，再内存中画图（验证码图片对象） 25 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); 26 27 //2 美化图片 28 //2.1 填充背景色 29 Graphics g = image.getGraphics();//画笔对象 30 g.setColor(Color.PINK);//设置画笔颜色 31 g.fillRect(0,0,width,height); 32 //2.2画边框 33 g.setColor(Color.BLUE); 34 g.drawRect(0,0,width - 1,height - 1); 35 //2.3画验证码 36 String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789"; 37 Random ran = new Random(); 38 //======================================== 39 StringBuilder sb = new StringBuilder(); 40 //======================================== 41 for (int i = 1; i <= 4; i++) { 42 //生成随机下标 43 int index = ran.nextInt(str.length()); 44 //获取随机字符 45 char ch = str.charAt(index); 46 sb.append(ch); 47 48 //写验证码 49 g.drawString(ch+"",width/5*i,height/2); 50 } 51 //======================================== 52 String checkCodeTruth = sb.toString(); 53 //将生成的验证码存入session 54 HttpSession session = request.getSession(); 55 session.setAttribute("checkCodeTruth", checkCodeTruth); 56 //======================================== 57 58 //2.4画干扰线 59 g.setColor(Color.GREEN); 60 for (int i = 0; i < 10; i++) { //随机生成坐标点 61 int x1 = ran.nextInt(width); 62 int x2 = ran.nextInt(width); 63 int y1 = ran.nextInt(height); 64 int y2 = ran.nextInt(height); 65 g.drawLine(x1,y1,x2,y2); 66 } 67 68 //3 将图片输出到页面展示 69 ImageIO.write(image, "jpg", response.getOutputStream()); 70 } 71 72 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 73 this.doPost(request, response); 74 } 75 }
