【web案例】赵雅智_校验验证码

来源：互联网发布：上班族减肥知乎编辑：程序博客网时间：2024/05/16 05:33

RandomImage.java
1. 保存src
2. 获取到src,把src写进去，把数字追加到字符缓冲区,把字符缓冲区内容返回给调用者,在方法前加返回值
3. 此方法有String返回值
4. 返回值
5. 调用setRandouNum()方法时,获取验证码内容
6. 获取session验证码是什么放到session里
LoginServlet.java
1. 获取填写的验证码
2. 与session里的值比较
3. 判断验证码是否一致
4. 设置字符集
login,html
1. 验证码看不清点击图片刷新

主页面：login.html

<!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">  </head>    <body>    <form action="/bookCookie/LoginServlet" method="post">    用户名：<input type="text" name="username"><br/><br/>  密码:<input type="password" name="password"><br/><br/>  验证码<input type="text" name="checkcode"><br>  <img src="./RandomImage"><br/><br/>  <input type="submit" value="登录">    </form>  </body></html>

新建servlet

RandomImage.java

package com.hbsi.session;import java.awt.*;import java.awt.image.BufferedImage;import java.io.IOException;import java.io.PrintWriter;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 RandomImage extends HttpServlet {public static final int WIDTH = 130;public static final int HEIGHT = 30;public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);Graphics g = image.getGraphics();setBackGrount(g);setBorder(g);setRandomLine(g);//5.调用setRandouNum()方法时,获取验证码内容String checkcode = setRandomNum(g);//6.获取session验证码是什么放到session里request.getSession().setAttribute("imgcode", checkcode);response.setContentType("image/jpeg");response.setHeader("Pragma", "no-cache");response.setHeader("Cache-Control", "no-cache");response.setIntHeader("Expires",-1);ImageIO.write(image,"JPEG",response.getOutputStream());}//产生验证码//3.此方法有String返回值private String setRandomNum(Graphics g) {// TODO Auto-generated method stub//g.setColor(Color.BLACK);g.setFont(new Font("宋体",Font.BOLD,20));Random random = new Random();//1.保存srcStringBuffer sb = new StringBuffer();int x=10;for(int i=0;i<4;i++){//产生随机数String str = String.valueOf(random.nextInt(10));//2.获取到src,把src写进去，把数字追加到字符缓冲区,把字符缓冲区内容返回给调用者,在方法前加返回值sb.append(str);g.setColor(new Color(random.nextInt(255),random.nextInt(255),random.nextInt(255)));int degree = random.nextInt()%30;((Graphics2D)g).rotate(degree*Math.PI/180, x, 20);g.drawString(str, x, 20);((Graphics2D)g).rotate(-degree*Math.PI/180, x, 20);x +=30;}//4.返回值return sb.toString();}private void setRandomLine(Graphics g) {// TODO Auto-generated method stubg.setColor(Color.blue);Random random = new Random();for(int i=0;i<5;i++){int x1 = random.nextInt(WIDTH);int y1 = random.nextInt(HEIGHT);int x2 = random.nextInt(WIDTH);int y2 = random.nextInt(HEIGHT);g.drawLine(x1, y1, x2, y2);}}private void setBorder(Graphics g) {// TODO Auto-generated method stubg.setColor(Color.BLUE);g.drawRect(1, 1, WIDTH-2, HEIGHT-2);}private void setBackGrount(Graphics g) {// TODO Auto-generated method stubg.setColor(Color.PINK);g.fillRect(0, 0, WIDTH, HEIGHT);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {}}

新建LoginServlet

package com.hbsi.session;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.hbsi.dao.UserDao;import com.hbsi.dao.UserDaoImpl;import com.hbsi.domian.User;public class LoginServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//        10.设置字符集response.setContentType("text/html;charset=UTF-8");PrintWriter out = response.getWriter();String username = request.getParameter("username");String password = request.getParameter("password");//7.获取填写的验证码String checkcode = request.getParameter("checkcode");//8.与session里的值比较String imgcode = (String) request.getSession().getAttribute("imgcode");//9.判断验证码是否一致if(checkcode!=null && imgcode!=null && checkcode.equals(imgcode)){//处理登陆请求UserDao ud = new UserDaoImpl();User user = ud.find(username, password);if(user!=null){request.getSession().setAttribute("user",user);response.sendRedirect("/bookCookie/IndexServlet");}out.print("用户名密码错");}else{out.print("验证码错误！！！");}}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}

验证码看不清点击图片刷新

<!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">    <script type="text/javascript">       function change(img){          img.src = img.src +"?"+ new Date().getTime();        }    </script>    <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->  </head>    <body>    <form action="/bookCookie/LoginServlet" method="post">    用户名：<input type="text" name="username"><br/><br/>  密码:<input type="password" name="password"><br/><br/>  验证码<input type="text" name="checkcode"><br>  <img src="./RandomImage" onclick="change(this)"><br/><br/>  <input type="submit" value="登录">    </form>  </body></html>

点击粉色图片后：