Session实现验证码登陆笔记

Myth丶恋晨 2021-11-23 09:50 436阅读 0赞

1.生成验证码Servlet

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  1. 1 package com.isit.servlet;
  2.  2 
  3.  3 import javax.imageio.ImageIO;
  4.  4 import javax.servlet.ServletException;
  5.  5 import javax.servlet.annotation.WebServlet;
  6.  6 import javax.servlet.http.HttpServlet;
  7.  7 import javax.servlet.http.HttpServletRequest;
  8.  8 import javax.servlet.http.HttpServletResponse;
  9.  9 import javax.servlet.http.HttpSession;
  10. 10 import java.awt.*;
  11. 11 import java.awt.image.BufferedImage;
  12. 12 import java.io.IOException;
  13. 13 import java.util.Random;
  14. 14 
  15. 15 @WebServlet("/checkCodeServlet")
  16. 16 public class CheckCodeServlet extends HttpServlet {
  17. 17     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  18. 18 
  19. 19 
  20. 20         int width = 100;
  21. 21         int height = 50;
  22. 22 
  23. 23         //1.创建一对象，在内存中图片(验证码图片对象)
  24. 24         BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
  25. 25 
  26. 26 
  27. 27         //2.美化图片
  28. 28         //2.1 填充背景色
  29. 29         Graphics g = image.getGraphics();//画笔对象
  30. 30         g.setColor(Color.PINK);//设置画笔颜色
  31. 31         g.fillRect(0, 0, width, height);
  32. 32 
  33. 33         //2.2画边框
  34. 34         g.setColor(Color.BLUE);
  35. 35         g.drawRect(0, 0, width - 1, height - 1);
  36. 36 
  37. 37         String str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789";
  38. 38         //生成随机角标
  39. 39         StringBuffer sb = new StringBuffer();
  40. 40         Random ran = new Random();
  41. 41         for (int i = 1; i <= 4; i++) {
  42. 42             int index = ran.nextInt(str.length());
  43. 43             //获取字符
  44. 44             char ch = str.charAt(index);//随机字符
  45. 45             sb.append(ch);
  46. 46             //2.3写验证码
  47. 47             g.drawString(ch + "", width / 5 * i, height / 2);
  48. 48         }
  49. 49         String checkCode = sb.toString();
  50. 50         HttpSession session = request.getSession();
  51. 51         session.setAttribute("checkCode", checkCode);
  52. 52         //2.4画干扰线
  53. 53         g.setColor(Color.GREEN);
  54. 54 
  55. 55         //随机生成坐标点
  56. 56 
  57. 57         for (int i = 0; i < 10; i++) {
  58. 58             int x1 = ran.nextInt(width);
  59. 59             int x2 = ran.nextInt(width);
  60. 60 
  61. 61             int y1 = ran.nextInt(height);
  62. 62             int y2 = ran.nextInt(height);
  63. 63             g.drawLine(x1, y1, x2, y2);
  64. 64         }
  65. 65 
  66. 66 
  67. 67         //3.将图片输出到页面展示
  68. 68         ImageIO.write(image, "jpg", response.getOutputStream());
  69. 69 
  70. 70 
  71. 71     }
  72. 72 
  73. 73     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  74. 74         this.doPost(request, response);
  75. 75     }
  76. 76 }

CheckCodeServlet

2.登陆Servlet

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  1. 1 package com.isit.servlet;
  2.  2 
  3.  3 import com.isit.dao.UserDao;
  4.  4 import com.isit.entity.User;
  5.  5 import org.apache.commons.beanutils.BeanUtils;
  6.  6 
  7.  7 import javax.servlet.ServletException;
  8.  8 import javax.servlet.annotation.WebServlet;
  9.  9 import javax.servlet.http.HttpServlet;
  10. 10 import javax.servlet.http.HttpServletRequest;
  11. 11 import javax.servlet.http.HttpServletResponse;
  12. 12 import javax.servlet.http.HttpSession;
  13. 13 import java.io.IOException;
  14. 14 import java.lang.reflect.InvocationTargetException;
  15. 15 import java.util.Map;
  16. 16 
  17. 17 /**
  18. 18  * @program: LoginServlet
  19. 19  * @description: 登陆
  20. 20  * @author: wxh
  21. 21  * @date: 2019-06-11 15:03
  22. 22  **/
  23. 23 @WebServlet("/loginServlet")
  24. 24 public class LoginServlet extends HttpServlet {
  25. 25     @Override
  26. 26     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  27. 27         this.doPost(req, resp);
  28. 28     }
  29. 29 
  30. 30     @Override
  31. 31     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  32. 32         req.setCharacterEncoding("utf-8");
  33. 33         //1.验证验证码是否正确
  34. 34         HttpSession session = req.getSession();
  35. 35         String checkCode = (String) session.getAttribute("checkCode");
  36. 36         //1.1.验证码错误
  37. 37         String code = req.getParameter("checkCode");
  38. 38         if (checkCode != null && !checkCode.equalsIgnoreCase(code)) {
  39. 39             req.setAttribute("msg", "验证码错误");
  40. 40             req.getRequestDispatcher("/index.jsp").forward(req, resp);
  41. 41         } else {
  42. 42             //1.2.验证码正确
  43. 43             //2.校验登陆密码
  44. 44             User user = new User();
  45. 45             Map<String, String[]> parameterMap = req.getParameterMap();
  46. 46             //使用BeanUtils工具类封装成JavaBean对象
  47. 47             try {
  48. 48                 BeanUtils.populate(user, parameterMap);
  49. 49             } catch (IllegalAccessException e) {
  50. 50                 e.printStackTrace();
  51. 51             } catch (InvocationTargetException e) {
  52. 52                 e.printStackTrace();
  53. 53             }
  54. 54             UserDao userDao = new UserDao();
  55. 55             User entity = userDao.checkUser(user);
  56. 56             if (entity != null) {
  57. 57                 //2.1.匹配重定向到登录成功 Success.jsp 页面
  58. 58                 session.setAttribute("username", entity.getUsername());
  59. 59                 resp.sendRedirect(req.getContextPath() + "/success.jsp");
  60. 60             } else {
  61. 61                 //2.2.不匹配，转发到登陆界面
  62. 62                 req.setAttribute("msg", "用户名或密码错误");
  63. 63                 req.getRequestDispatcher("/index.jsp").forward(req, resp);
  64. 64             }
  65. 65         }
  66. 66     }
  67. 67 }

LoginServlet

3.JavaBean实体类代码

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  1. 1 package com.isit.entity;
  2.  2 
  3.  3 /**
  4.  4  * @program: User
  5.  5  * @description: User实体类
  6.  6  * @author: wxh
  7.  7  * @date: 2019-06-11 14:15
  8.  8  **/
  9.  9 public class User {
  10. 10     private String id;
  11. 11     private String username;
  12. 12     private String password;
  13. 13 
  14. 14     public String getId() {
  15. 15         return id;
  16. 16     }
  17. 17 
  18. 18     public void setId(String id) {
  19. 19         this.id = id;
  20. 20     }
  21. 21 
  22. 22     public String getUsername() {
  23. 23         return username;
  24. 24     }
  25. 25 
  26. 26     public void setUsername(String username) {
  27. 27         this.username = username;
  28. 28     }
  29. 29 
  30. 30     public String getPassword() {
  31. 31         return password;
  32. 32     }
  33. 33 
  34. 34     public void setPassword(String password) {
  35. 35         this.password = password;
  36. 36     }
  37. 37 }

User

4.UserDao数据库操作层

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  1. 1 package com.isit.dao;
  2.  2 
  3.  3 import com.isit.entity.User;
  4.  4 import com.isit.utils.JDBCUtils;
  5.  5 import org.springframework.jdbc.core.JdbcTemplate;
  6.  6 import org.springframework.jdbc.core.RowMapper;
  7.  7 
  8.  8 import java.sql.ResultSet;
  9.  9 import java.sql.SQLException;
  10. 10 
  11. 11 /**
  12. 12  * @program: UserDao
  13. 13  * @description: UserDao
  14. 14  * @author: wxh
  15. 15  * @date: 2019-06-11 14:46
  16. 16  **/
  17. 17 public class UserDao {
  18. 18     JdbcTemplate jdbcTemplate = new JdbcTemplate(JDBCUtils.getDataSource());
  19. 19 
  20. 20     public User checkUser(User user){
  21. 21         String sql = "select * from user where username = ? and password = ?";
  22. 22         try{
  23. 23             User entity= jdbcTemplate.queryForObject(sql, new RowMapper<User>() {
  24. 24                 @Override
  25. 25                 public User mapRow(ResultSet resultSet, int i) throws SQLException {
  26. 26                     User user = new User();
  27. 27                     String username = resultSet.getString("username");
  28. 28                     String password = resultSet.getString("password");
  29. 29                     user.setUsername(username);
  30. 30                     user.setPassword(password);
  31. 31                     return user;
  32. 32                 }
  33. 33             },user.getUsername(),user.getPassword());
  34. 34             return entity;
  35. 35         }catch (Exception e){
  36. 36             e.printStackTrace();
  37. 37             return null;
  38. 38         }
  39. 39     }
  40. 40 
  41. 41 }

UserDao

5.JDBC工具类

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  1. 1 package com.isit.utils;
  2.  2 
  3.  3 import com.alibaba.druid.pool.DruidDataSourceFactory;
  4.  4 
  5.  5 import javax.sql.DataSource;
  6.  6 import java.io.IOException;
  7.  7 import java.io.InputStream;
  8.  8 import java.sql.Connection;
  9.  9 import java.sql.ResultSet;
  10. 10 import java.sql.SQLException;
  11. 11 import java.sql.Statement;
  12. 12 import java.util.Properties;
  13. 13 
  14. 14 /**
  15. 15  * @program: JDBCUtils
  16. 16  * @description: 数据库连接池工具类
  17. 17  * @author: wxh
  18. 18  * @date: 2019-06-11 14:17
  19. 19  **/
  20. 20 public class JDBCUtils {
  21. 21 
  22. 22     private static DataSource ds;
  23. 23     static {
  24. 24         Properties properties = new Properties();
  25. 25         InputStream resourceAsStream = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
  26. 26         try {
  27. 27             properties.load(resourceAsStream);
  28. 28             ds = DruidDataSourceFactory.createDataSource(properties);
  29. 29         } catch (IOException e) {
  30. 30             e.printStackTrace();
  31. 31         }catch (Exception e) {
  32. 32             e.printStackTrace();
  33. 33         }
  34. 34     }
  35. 35 
  36. 36     public static DataSource getDataSource(){
  37. 37         return ds;
  38. 38     }
  39. 39 
  40. 40     public static Connection getConnection() throws SQLException {
  41. 41         return ds.getConnection();
  42. 42     }
  43. 43 
  44. 44     public static void close(Connection con, Statement statement, ResultSet resultSet){
  45. 45         if(resultSet !=null){
  46. 46             try {
  47. 47                 resultSet.close();
  48. 48             } catch (SQLException e) {
  49. 49                 e.printStackTrace();
  50. 50             }
  51. 51         }
  52. 52         if(statement!=null){
  53. 53             try {
  54. 54                 statement.close();
  55. 55             } catch (SQLException e) {
  56. 56                 e.printStackTrace();
  57. 57             }
  58. 58         }
  59. 59         if(con!=null){
  60. 60             try {
  61. 61                 con.close();
  62. 62             } catch (SQLException e) {
  63. 63                 e.printStackTrace();
  64. 64             }
  65. 65         }
  66. 66     }
  67. 67 
  68. 68     public static void close(Connection connection,Statement statement){
  69. 69         close(connection,statement,null);
  70. 70     }
  71. 71 
  72. 72 }

JDBCUtils

6.JSP页面

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  1. 1 <%--
  2.  2   Created by IntelliJ IDEA.
  3.  3   User: isit
  4.  4   Date: 2019/6/11
  5.  5   Time: 14:09
  6.  6   To change this template use File | Settings | File Templates.
  7.  7 --%>
  8.  8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
  9.  9 <html>
  10. 10   <head>
  11. 11     <title>登陆</title>
  12. 12     <script>
  13. 13       window.onload= function () {
  14. 14         document.getElementById("img").onclick=function () {
  15. 15           this.src = "/loginJsp/checkCodeServlet?time="+ new Date().getTime();
  16. 16         }
  17. 17       }
  18. 18     </script>
  19. 19   </head>
  20. 20 
  21. 21   <body>
  22. 22   <form method="post" action="/loginJsp/loginServlet">
  23. 23     <div>登录名：<input type="text" name="username"></div>
  24. 24     <div>密  码：<input type="password" name="password"></div>
  25. 25     <div><img src="/loginJsp/checkCodeServlet" id="img"></div>
  26. 26     <div> <input type="text" name="checkCode"></div>
  27. 27     <div><input type="submit"></div>
  28. 28   </form>
  29. 29   <div><%=request.getAttribute("msg")%></div>
  30. 30   </body>
  31. 31 </html>

index.jsp

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  1. 1 <%--
  2.  2   Created by IntelliJ IDEA.
  3.  3   User: isit
  4.  4   Date: 2019/6/11
  5.  5   Time: 16:11
  6.  6   To change this template use File | Settings | File Templates.
  7.  7 --%>
  8.  8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
  9.  9 <html>
  10. 10 <head>
  11. 11     <title>登陆成功</title>
  12. 12 </head>
  13. 13 <body>
  14. 14 <h1>
  15. 15     <%=request.getSession().getAttribute("username")%> ，登陆成功
  16. 16 </h1>
  17. 17 </body>
  18. 18 </html>

success.jsp

总结：

1.实现登陆操作需要验证码Servlet和登陆Servlet两个Servlet，一个会话中需要请求两次，一个生成验证码图片，一个做验证操作（验证码匹配和登陆账号密码匹配）；

2.CheckCodeServlet生成验证码图片到index.jsp页面，并将生成的验证码存到session中，以供LoginServlet做验证码验证操作；

3.LoginServlet需要两步验证，（1）验证验证码（2）验证登陆名和密码

3.1.通过HttpServletRequst对象获取Session对象，从Session对象中获取CheckCodeServlet添加到session中的验证码，以做验证操作，成功，继续下一步的登陆名和密码操作，失败，转发到登陆index.jsp页面，提示验证码错误；

3.2.验证码校验通过后，通过Dao层操作数据库返回查询结果（使用Druid数据库连接池，并使用JDBCTemple对数据库连接池对象进行封装，执行queryForObject方法返回实体类User）

3.3.校验通过，设置登陆名到session中（setAttribute），重定向到success.jsp页面，jsp页面取session中存放的登录名，展示XXX，登陆成功；

3.4.校验失败，转发到index.jsp页面中，提示登陆名密码错误。

转载于:https://www.cnblogs.com/isit/p/11004766.html

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