zoukankan html css js c++ java

案例:用户的注册和登录功能

知识点

①MVC设计模式

②文件上传功能

③验证码的校验

什么是MVC?

JavaWeb开发历程

案例实现

1)环境搭建

用户注册

　　- 用户信息的保存

　　- 用户头像的上传

如果注册成功会跳转到登陆页面

创建一个工程

将样式,图片和页面放到webcontent目录下

将需要用到的jar包放到lib目录中

将工程发布到tomcat

2)用户列表初始化

这个案例将账户数据存放在了集合中放到servlet的全局域.

知识点:监听器

domain 实体类:User类

service 接口,用于处理业务逻辑

utils 工具类

listener 监听器:初始化用户信息监听器

servlet servlet类

User.java

 1 package com.imooc.domain;
 2 
 3 public class User {
 4     private String username;
 5     private String password;
 6     
 7     private String path;
 8 
 9     public String getUsername() {
10         return username;
11     }
12 
13     public void setUsername(String username) {
14         this.username = username;
15     }
16 
17     public String getPassword() {
18         return password;
19     }
20 
21     public void setPassword(String password) {
22         this.password = password;
23     }
24 
25     public String getPath() {
26         return path;
27     }
28 
29     public void setPath(String path) {
30         this.path = path;
31     }
32 
33     @Override
34     public String toString() {
35         return "User [username=" + username + ", password=" + password + ", path=" + path + "]";
36     }
37     
38     
39 }

View Code

监听器

3)注册页面的表单校验

注册页面的form表单

script标签

4)用户信息保存

form表单

接口

注册servlet

5)上传文件功能

原理分析:

但这时接收到的请求参数只有文件名,没有文件

增加enctype属性

原理:拿到请求后,对请求做一个相应的解析

fileload简介:

官网地址:http://commons.apache.org/proper/commons-fileupload/

UploadServlet

 1 package com.imooc.servlet;
 2 
 3 import java.io.FileOutputStream;
 4 import java.io.IOException;
 5 import java.io.InputStream;
 6 import java.io.OutputStream;
 7 import java.util.List;
 8 
 9 import javax.servlet.ServletException;
10 import javax.servlet.annotation.WebServlet;
11 import javax.servlet.http.HttpServlet;
12 import javax.servlet.http.HttpServletRequest;
13 import javax.servlet.http.HttpServletResponse;
14 
15 import org.apache.commons.fileupload.FileItem;
16 import org.apache.commons.fileupload.FileUploadException;
17 import org.apache.commons.fileupload.disk.DiskFileItemFactory;
18 import org.apache.commons.fileupload.servlet.ServletFileUpload;
19 
20 @WebServlet("/UploadServlet")
21 public class UploadServlet extends HttpServlet {
22     private static final long serialVersionUID = 1L;
23 
24     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
25     
26         // 1.创建磁盘文件项工厂
27         DiskFileItemFactory diskFileItemFactory = new DiskFileItemFactory();
28         // 2.创建核心解析类
29         ServletFileUpload fileUpload = new ServletFileUpload(diskFileItemFactory);
30         // 3.解析请求对象,将请求分成几个部分(FileItem)
31         try {
32             List<FileItem> list= fileUpload.parseRequest(request);
33             // 4.遍历集合获得每个部分的对象
34             for(FileItem fileItem:list){
35                 // 判断是普通项还是文件上传项
36                 if(fileItem.isFormField()){
37                     // 普通项
38                     // 获得普通项的名称:
39                     String name = fileItem.getFieldName();
40                     // 获得普通项的值:
41                     String value = fileItem.getString("UTF-8");
42                     System.out.println(name+"  "+value);
43                 }else{
44                     // 文件上传项
45                     // 获得文件的名称:
46                     String fileName = fileItem.getName();
47                     // 获得文件的输入流:
48                     InputStream is = fileItem.getInputStream();
49                     // 需要将文件写入到服务器的某个路径即可:
50                     String path = getServletContext().getRealPath("/upload");
51                     System.out.println(path);
52                     // 创建输出流 与 输入流进行对接:
53                     OutputStream os = new FileOutputStream(path+"\"+fileName);
54                     int len = 0;
55                     byte[] b = new byte[1024];
56                     while((len = is.read(b))!=-1){
57                         os.write(b, 0, len);
58                     }
59                     is.close();
60                     os.close();
61                 }
62             }
63         } catch (FileUploadException e) {
64             // TODO Auto-generated catch block
65             e.printStackTrace();
66         }
67     
68     }
69 
70     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
71         doGet(request, response);
72     }
73 
74 }

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6)用户头像上传

  1 package com.imooc.web.servlet;
  2 
  3 import java.io.FileOutputStream;
  4 import java.io.IOException;
  5 import java.io.InputStream;
  6 import java.io.OutputStream;
  7 import java.util.HashMap;
  8 import java.util.List;
  9 import java.util.Map;
 10 
 11 import javax.servlet.ServletException;
 12 import javax.servlet.annotation.WebServlet;
 13 import javax.servlet.http.HttpServlet;
 14 import javax.servlet.http.HttpServletRequest;
 15 import javax.servlet.http.HttpServletResponse;
 16 
 17 import org.apache.commons.fileupload.FileItem;
 18 import org.apache.commons.fileupload.FileUploadException;
 19 import org.apache.commons.fileupload.disk.DiskFileItemFactory;
 20 import org.apache.commons.fileupload.servlet.ServletFileUpload;
 21 
 22 import com.imooc.domain.User;
 23 import com.imooc.service.UserService;
 24 import com.imooc.service.impl.UserServiceImpl;
 25 import com.imooc.utils.UploadUtils;
 26 
 27 @WebServlet("/RegistServlet")
 28 public class RegistServlet extends HttpServlet {
 29     private static final long serialVersionUID = 1L;
 30 
 31     protected void doGet(HttpServletRequest request, HttpServletResponse response)
 32             throws ServletException, IOException {
 33         // 接收数据
 34         // 创建Map集合用于保存数据:
 35         Map<String,String> map = new HashMap<String,String>();
 36         // 文件上传的代码:
 37         // 1.创建磁盘文件项工厂
 38         DiskFileItemFactory diskFileItemFactory = new DiskFileItemFactory();
 39         // 2.创建核心解析类
 40         ServletFileUpload fileUpload = new ServletFileUpload(diskFileItemFactory);
 41         // 3.解析请求对象,将请求分成几个部分(FileItem)
 42         try {
 43             List<FileItem> list = fileUpload.parseRequest(request);
 44             // 4.遍历集合获得每个部分的对象
 45             for (FileItem fileItem : list) {
 46                 // 判断是普通项还是文件上传项
 47                 if (fileItem.isFormField()) {
 48                     // 普通项--用户名(username--输入的值) 密码 确认密码
 49                     // 获得普通项的名称:
 50                     String name = fileItem.getFieldName();
 51                     // 获得普通项的值:
 52                     String value = fileItem.getString("UTF-8");
 53                     // 保存数据:
 54                     map.put(name, value);
 55                 } else {
 56                     // 文件上传项
 57                     // 获得文件的名称:
 58                     String fileName = fileItem.getName();
 59                     // 获得唯一文件名:
 60                     String uuidFileName = UploadUtils.getUuidFileName(fileName);
 61                     // 获得文件的输入流:
 62                     InputStream is = fileItem.getInputStream();
 63                     // 需要将文件写入到服务器的某个路径即可:
 64                     String path = getServletContext().getRealPath("/upload");
 65                     System.out.println(path);// D:/xxx/ddd/
 66                     // 显示图片<img src="/regist_login/upload/a.jpg">
 67                     // 创建输出流 与 输入流进行对接:
 68                     String url = path + "\" + uuidFileName;
 69                     map.put("path", request.getContextPath()+"/upload/"+uuidFileName);
 70                     OutputStream os = new FileOutputStream(url);
 71                     int len = 0;
 72                     byte[] b = new byte[1024];
 73                     while ((len = is.read(b)) != -1) {
 74                         os.write(b, 0, len);
 75                     }
 76                     is.close();
 77                     os.close();
 78                 }
 79             }
 80         } catch (FileUploadException e) {
 81             // TODO Auto-generated catch block
 82             e.printStackTrace();
 83         }
 84 
 85         // 封装数据
 86         User user = new User();
 87         user.setUsername(map.get("username"));
 88         user.setPassword(map.get("password"));
 89         
 90         user.setPath(map.get("path"));
 91         System.out.println(user);
 92         // 处理数据
 93         UserService userService = new UserServiceImpl();
 94         // 从ServletContext域中获取用户的集合即可
 95         List<User> userList = (List<User>) getServletContext().getAttribute("userList");
 96         userService.regist(userList, user);
 97         System.out.println(userList);
 98         // 显示处理结果
 99         response.sendRedirect(request.getContextPath() + "/login.jsp");
100     }
101 
102     protected void doPost(HttpServletRequest request, HttpServletResponse response)
103             throws ServletException, IOException {
104         doGet(request, response);
105     }
106 
107 }

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7)解决文件名重名问题

 1 package com.imooc.utils;
 2 
 3 import java.util.UUID;
 4 
 5 public class UploadUtils {
 6     
 7     public static String getUuidFileName(String fileName){
 8         // 解决文件重名的问题:   
 9         // a.jpg  -- 获得后缀名.jpg -- 生成一段随机字符串将a替换掉 xxdfwerw.jpg
10         int idx = fileName.lastIndexOf(".");
11         String exName = fileName.substring(idx);// .jpg
12         // 生成随机字符串:
13         String uuidFileName = UUID.randomUUID().toString().replace("-", "")+exName;
14     
15         return uuidFileName;
16     }
17     
18     public static void main(String[] args) {
19         System.out.println(UploadUtils.getUuidFileName("a.jpg"));
20     }
21 }

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8)登录功能

用户信息查询

loginservlet

 1 package com.imooc.web.servlet;
 2 
 3 import java.io.IOException;
 4 import java.util.List;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 
12 import com.imooc.domain.User;
13 import com.imooc.service.UserService;
14 import com.imooc.service.impl.UserServiceImpl;
15 
16 @WebServlet("/LoginServlet")
17 public class LoginServlet extends HttpServlet {
18     private static final long serialVersionUID = 1L;
19 
20     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
21         
22         // 接收数据:
23         String username = request.getParameter("username");
24         String password = request.getParameter("password");
25         // 封装数据:
26         User user = new User();
27         user.setUsername(username);
28         user.setPassword(password);
29         // 处理数据:完成登陆.
30         UserService userService = new UserServiceImpl();
31         // 获得用户列表的集合:
32         List<User> userList = (List<User>)getServletContext().getAttribute("userList");
33         User existUser = userService.login(userList,user);
34         // 显示结果:
35         if(existUser == null){
36             // 登录失败
37             request.setAttribute("msg", "用户名或密码错误!");
38             request.getRequestDispatcher("/login.jsp").forward(request, response);
39         }else{
40             // 登录成功
41             // 将用户信息保存:
42             request.getSession().setAttribute("existUser", existUser);
43             response.sendRedirect(request.getContextPath()+"/index.jsp");
44         }
45     }
46 
47     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
48         doGet(request, response);
49     }
50 
51 }

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接口实现类

 1 package com.imooc.service.impl;
 2 
 3 import java.util.List;
 4 
 5 import com.imooc.domain.User;
 6 import com.imooc.service.UserService;
 7 
 8 public class UserServiceImpl implements UserService {
 9 
10     @Override
11     public void regist(List<User> userList, User user) {
12         // 保存用户信息:
13         userList.add(user);
14     }
15 
16     @Override
17     public User login(List<User> userList, User user) {
18         
19         for (User existUser : userList) {
20             if(existUser.getUsername().equals(user.getUsername()) && existUser.getPassword().equals(user.getPassword())){
21                 return existUser;
22             }
23         }
24         
25         return null;
26     }
27 
28 }

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首页头部:设置登录成功和失败的样式

1 <c:if test="${ empty existUser }">
2          <li><a href="${pageContext.request.contextPath }/login.jsp">登录</a></li>
3         <li><a href="${pageContext.request.contextPath }/register.jsp">注册</a></li>
4      </c:if>    
5      <c:if test="${ not empty existUser}">
6         <li>
7             <img class="profile_item" src="${ existUser.path }">
8         </li>
9     </c:if>

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9)验证码的生成与校验

概述

生成

验证码生成准备工作:

servlet

 1 package com.imooc.web.servlet;
 2 
 3 import java.awt.Color;
 4 import java.awt.Font;
 5 import java.awt.Graphics;
 6 import java.awt.Graphics2D;
 7 import java.awt.image.BufferedImage;
 8 import java.io.IOException;
 9 import java.util.Random;
10 
11 import javax.imageio.ImageIO;
12 import javax.servlet.ServletException;
13 import javax.servlet.annotation.WebServlet;
14 import javax.servlet.http.HttpServlet;
15 import javax.servlet.http.HttpServletRequest;
16 import javax.servlet.http.HttpServletResponse;
17 
18 @WebServlet("/CheckImgServlet1")
19 public class CheckImgServlet1 extends HttpServlet {
20     private static final long serialVersionUID = 1L;
21 
22     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
23         
24     }
25 
26     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
27         doGet(request, response);
28     }
29 
30 }

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页面

 1 <%@ page language="java" contentType="text/html; charset=UTF-8"
 2     pageEncoding="UTF-8"%>
 3 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
 4 <html>
 5 <head>
 6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 7 <title>Insert title here</title>
 8 </head>
 9 <body>
10     <form action="" method="post">
11         验证码:<input type="text" name="checkcode"/><img src="${pageContext.request.contextPath }/CheckImgServlet"><br/>
12         <input type="submit" value="提交">
13     </form>
14 </body>
15 </html>

View Code

将内存中图片显示到浏览器

servlet

字母随机旋转一定角度

 1 package com.imooc.web.servlet;
 2 
 3 import java.awt.Color;
 4 import java.awt.Font;
 5 import java.awt.Graphics;
 6 import java.awt.Graphics2D;
 7 import java.awt.image.BufferedImage;
 8 import java.io.IOException;
 9 import java.util.Random;
10 
11 import javax.imageio.ImageIO;
12 import javax.servlet.ServletException;
13 import javax.servlet.annotation.WebServlet;
14 import javax.servlet.http.HttpServlet;
15 import javax.servlet.http.HttpServletRequest;
16 import javax.servlet.http.HttpServletResponse;
17 
18 @WebServlet("/CheckImgServlet1")
19 public class CheckImgServlet1 extends HttpServlet {
20     private static final long serialVersionUID = 1L;
21 
22     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
23         int width = 120;
24         int height = 30;
25         // 步骤一:在内存中生成一张图片
26         BufferedImage bufferedImage = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
27         // 步骤二:操作该图片,设置背景色及绘制边框
28         Graphics graphics = bufferedImage.getGraphics();
29         // 设置背景色
30         graphics.setColor(Color.YELLOW);
31         graphics.fillRect(0, 0, width, height);
32         // 绘制边框
33         graphics.setColor(Color.BLUE);
34         graphics.drawRect(0, 0, width-1, height-1);
35         
36         // 步骤三:生成随机的四个字母或数字,写入到图片中
37         Graphics2D g2d = (Graphics2D)graphics;
38         g2d.setColor(Color.BLACK);
39         g2d.setFont(new Font("宋体",Font.BOLD,18));//a 4 3 r
40         
41         String words = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
42         Random random = new Random();
43         int x = 10;
44         for(int i=0;i<4;i++){
45             int idx = random.nextInt(words.length());
46             // 获得指定位置的字符
47             char ch = words.charAt(idx);
48             // 旋转的角度  -30 到 30 之间
49             int jiaodu = random.nextInt(60) - 30;
50             // 将角度转化成弧度:
51             double theta = jiaodu * Math.PI / 180;
52             g2d.rotate(theta, x, 20);
53             g2d.drawString(String.valueOf(ch), x, 20);
54             g2d.rotate(-theta, x, 20);
55             
56             x+=30;
57         }
58         // 步骤四:将内存中的图片,进行输出
59         ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
60     }
61 
62     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
63         doGet(request, response);
64     }
65 
66 }

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添加干扰线以及设置字母随机颜色

  1 package com.imooc.web.servlet;
  2 
  3 import java.awt.Color;
  4 import java.awt.Font;
  5 import java.awt.Graphics;
  6 import java.awt.Graphics2D;
  7 import java.awt.image.BufferedImage;
  8 import java.io.IOException;
  9 import java.util.Random;
 10 
 11 import javax.imageio.ImageIO;
 12 import javax.servlet.ServletException;
 13 import javax.servlet.annotation.WebServlet;
 14 import javax.servlet.http.HttpServlet;
 15 import javax.servlet.http.HttpServletRequest;
 16 import javax.servlet.http.HttpServletResponse;
 17 
 18 /**
 19  * 生成验证码图片
 20  */
 21 @WebServlet("/CheckImgServlet")
 22 public class CheckImgServlet extends HttpServlet {
 23 
 24     public void doGet(HttpServletRequest request, HttpServletResponse response)
 25             throws ServletException, IOException {
 26 
 27         int width = 120;
 28         int height = 30;
 29 
 30         // 步骤一 绘制一张内存中图片
 31         BufferedImage bufferedImage = new BufferedImage(width, height,
 32                 BufferedImage.TYPE_INT_RGB);
 33 
 34         // 步骤二 图片绘制背景颜色 ---通过绘图对象
 35         Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔
 36         // 绘制任何图形之前 都必须指定一个颜色
 37         graphics.setColor(getRandColor(200, 250));
 38         graphics.fillRect(0, 0, width, height);
 39 
 40         // 步骤三 绘制边框
 41         graphics.setColor(Color.WHITE);
 42         graphics.drawRect(0, 0, width - 1, height - 1);
 43 
 44         // 步骤四 四个随机数字
 45         Graphics2D graphics2d = (Graphics2D) graphics;
 46         // 设置输出字体
 47         graphics2d.setFont(new Font("宋体", Font.BOLD, 18));
 48 
 49         String words =
 50          "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
 51         // String words = "u7684u4e00u4e86u662fu6211u4e0du5728u4ebau4eecu6709u6765u4ed6u8fd9u4e0au7740u4e2au5730u5230u5927u91ccu8bf4u5c31u53bbu5b50u5f97u4e5fu548cu90a3u8981u4e0bu770bu5929u65f6u8fc7u51fau5c0fu4e48u8d77u4f60u90fdu628au597du8fd8u591au6ca1u4e3au53c8u53efu5bb6u5b66u53eau4ee5u4e3bu4f1au6837u5e74u60f3u751fu540cu8001u4e2du5341u4eceu81eau9762u524du5934u9053u5b83u540eu7136u8d70u5f88u50cfu89c1u4e24u7528u5979u56fdu52a8u8fdbu6210u56deu4ec0u8fb9u4f5cu5bf9u5f00u800cu5df1u4e9bu73b0u5c71u6c11u5019u7ecfu53d1u5de5u5411u4e8bu547du7ed9u957fu6c34u51e0u4e49u4e09u58f0u4e8eu9ad8u624bu77e5u7406u773cu5fd7u70b9u5fc3u6218u4e8cu95eeu4f46u8eabu65b9u5b9eu5403u505au53ebu5f53u4f4fu542cu9769u6253u5462u771fu5168u624du56dbu5df2u6240u654cu4e4bu6700u5149u4ea7u60c5u8defu5206u603bu6761u767du8bddu4e1cu5e2du6b21u4eb2u5982u88abu82b1u53e3u653eu513fu5e38u6c14u4e94u7b2cu4f7fu5199u519bu5427u6587u8fd0u518du679cu600eu5b9au8bb8u5febu660eu884cu56e0u522bu98deu5916u6811u7269u6d3bu90e8u95e8u65e0u5f80u8239u671bu65b0u5e26u961fu5148u529bu5b8cu5374u7ad9u4ee3u5458u673au66f4u4e5du60a8u6bcfu98ceu7ea7u8ddfu7b11u554au5b69u4e07u5c11u76f4u610fu591cu6bd4u9636u8fdeu8f66u91cdu4fbfu6597u9a6cu54eau5316u592au6307u53d8u793eu4f3cu58ebu8005u5e72u77f3u6ee1u65e5u51b3u767eu539fu62ffu7fa4u7a76u5404u516du672cu601du89e3u7acbu6cb3u6751u516bu96beu65e9u8bbau5417u6839u5171u8ba9u76f8u7814u4ecau5176u4e66u5750u63a5u5e94u5173u4fe1u89c9u6b65u53cdu5904u8bb0u5c06u5343u627eu4e89u9886u6216u5e08u7ed3u5757u8dd1u8c01u8349u8d8au5b57u52a0u811au7d27u7231u7b49u4e60u9635u6015u6708u9752u534au706bu6cd5u9898u5efau8d76u4f4du5531u6d77u4e03u5973u4efbu4ef6u611fu51c6u5f20u56e2u5c4bu79bbu8272u8138u7247u79d1u5012u775bu5229u4e16u521au4e14u7531u9001u5207u661fu5bfcu665au8868u591fu6574u8ba4u54cdu96eau6d41u672au573au8be5u5e76u5e95u6df1u523bu5e73u4f1fu5fd9u63d0u786eu8fd1u4eaeu8f7bu8bb2u519cu53e4u9ed1u544au754cu62c9u540du5440u571fu6e05u9633u7167u529eu53f2u6539u5386u8f6cu753bu9020u5634u6b64u6cbbu5317u5fc5u670du96e8u7a7fu5185u8bc6u9a8cu4f20u4e1au83dcu722cu7761u5174u5f62u91cfu54b1u89c2u82e6u4f53u4f17u901au51b2u5408u7834u53cbu5ea6u672fu996du516cu65c1u623fu6781u5357u67aau8bfbu6c99u5c81u7ebfu91ceu575au7a7au6536u7b97u81f3u653fu57ceu52b3u843du94b1u7279u56f4u5f1fu80dcu6559u70edu5c55u5305u6b4cu7c7bu6e10u5f3au6570u4e61u547cu6027u97f3u7b54u54e5u9645u65e7u795eu5ea7u7ae0u5e2eu5566u53d7u7cfbu4ee4u8df3u975eu4f55u725bu53d6u5165u5cb8u6562u6389u5ffdu79cdu88c5u9876u6025u6797u505cu606fu53e5u533au8863u822cu62a5u53f6u538bu6162u53d4u80ccu7ec6";
 52         Random random = new Random();// 生成随机数
 53 
 54         // 定义x坐标
 55         int x = 10;
 56         for (int i = 0; i < 4; i++) {
 57             // 随机颜色
 58             graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random
 59                     .nextInt(110), 20 + random.nextInt(110)));
 60             // 旋转 -30 --- 30度
 61             int jiaodu = random.nextInt(60) - 30;
 62             // 换算弧度
 63             double theta = jiaodu * Math.PI / 180;
 64 
 65             // 生成一个随机数字
 66             int index = random.nextInt(words.length()); // 生成随机数 0 到 length - 1
 67             // 获得字母数字
 68             char c = words.charAt(index);
 69 
 70             // 将c 输出到图片
 71             graphics2d.rotate(theta, x, 20);
 72             graphics2d.drawString(String.valueOf(c), x, 20);
 73             graphics2d.rotate(-theta, x, 20);
 74             x += 30;
 75         }
 76 
 77         // 步骤五 绘制干扰线
 78         graphics.setColor(getRandColor(160, 200));
 79         int x1;
 80         int x2;
 81         int y1;
 82         int y2;
 83         for (int i = 0; i < 30; i++) {
 84             x1 = random.nextInt(width);
 85             x2 = random.nextInt(12);
 86             y1 = random.nextInt(height);
 87             y2 = random.nextInt(12);
 88             graphics.drawLine(x1, y1, x1 + x2, x2 + y2);
 89         }
 90 
 91         // 将上面图片输出到浏览器 ImageIO
 92         graphics.dispose();// 释放资源
 93         ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
 94 
 95     }
 96 
 97 
 98     public void doPost(HttpServletRequest request, HttpServletResponse response)
 99             throws ServletException, IOException {
100         doGet(request, response);
101     }
102 
103     /**
104      * 取其某一范围的color
105      * 
106      * @param fc
107      *            int 范围参数1
108      * @param bc
109      *            int 范围参数2
110      * @return Color
111      */
112     private Color getRandColor(int fc, int bc) {
113         // 取其随机颜色
114         Random random = new Random();
115         if (fc > 255) {
116             fc = 255;
117         }
118         if (bc > 255) {
119             bc = 255;
120         }
121         int r = fc + random.nextInt(bc - fc);
122         int g = fc + random.nextInt(bc - fc);
123         int b = fc + random.nextInt(bc - fc);
124         return new Color(r, g, b);
125     }
126 
127 }

View Code

实现验证码看不清更换一张的功能

页面

浏览器有缓存要更换每次请求的路径才能实现点击更换图片

校验

checkImgServlet

  1 package com.imooc.web.servlet;
  2 
  3 import java.awt.Color;
  4 import java.awt.Font;
  5 import java.awt.Graphics;
  6 import java.awt.Graphics2D;
  7 import java.awt.image.BufferedImage;
  8 import java.io.IOException;
  9 import java.util.Random;
 10 
 11 import javax.imageio.ImageIO;
 12 import javax.servlet.ServletException;
 13 import javax.servlet.annotation.WebServlet;
 14 import javax.servlet.http.HttpServlet;
 15 import javax.servlet.http.HttpServletRequest;
 16 import javax.servlet.http.HttpServletResponse;
 17 
 18 /**
 19  * 生成验证码图片
 20  */
 21 @WebServlet("/CheckImgServlet")
 22 public class CheckImgServlet extends HttpServlet {
 23 
 24     public void doGet(HttpServletRequest request, HttpServletResponse response)
 25             throws ServletException, IOException {
 26 
 27         int width = 120;
 28         int height = 30;
 29 
 30         // 步骤一 绘制一张内存中图片
 31         BufferedImage bufferedImage = new BufferedImage(width, height,
 32                 BufferedImage.TYPE_INT_RGB);
 33 
 34         // 步骤二 图片绘制背景颜色 ---通过绘图对象
 35         Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔
 36         // 绘制任何图形之前 都必须指定一个颜色
 37         graphics.setColor(getRandColor(200, 250));
 38         graphics.fillRect(0, 0, width, height);
 39 
 40         // 步骤三 绘制边框
 41         graphics.setColor(Color.WHITE);
 42         graphics.drawRect(0, 0, width - 1, height - 1);
 43 
 44         // 步骤四 四个随机数字
 45         Graphics2D graphics2d = (Graphics2D) graphics;
 46         // 设置输出字体
 47         graphics2d.setFont(new Font("宋体", Font.BOLD, 18));
 48 
 49         String words =
 50          "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
 51         // String words = "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";
 52         Random random = new Random();// 生成随机数
 53         // 定义一个字符串,用于保存随机产生的四个字母或数字
 54         StringBuffer sb = new StringBuffer();
 55         // 定义x坐标
 56         int x = 10;
 57         for (int i = 0; i < 4; i++) {
 58             // 随机颜色
 59             graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random
 60                     .nextInt(110), 20 + random.nextInt(110)));
 61             // 旋转 -30 --- 30度
 62             int jiaodu = random.nextInt(60) - 30;
 63             // 换算弧度
 64             double theta = jiaodu * Math.PI / 180;
 65 
 66             // 生成一个随机数字
 67             int index = random.nextInt(words.length()); // 生成随机数 0 到 length - 1
 68             // 获得字母数字
 69             char c = words.charAt(index);
 70             // 将产生字符存入到StringBuffer中
 71             sb.append(c);
 72             // 将c 输出到图片
 73             graphics2d.rotate(theta, x, 20);
 74             graphics2d.drawString(String.valueOf(c), x, 20);
 75             graphics2d.rotate(-theta, x, 20);
 76             x += 30;
 77         }
 78         // 将产生的字符串存入到session中:
 79         request.getSession().setAttribute("checkCode", sb.toString());
 80 
 81         // 步骤五 绘制干扰线
 82         graphics.setColor(getRandColor(160, 200));
 83         int x1;
 84         int x2;
 85         int y1;
 86         int y2;
 87         for (int i = 0; i < 30; i++) {
 88             x1 = random.nextInt(width);
 89             x2 = random.nextInt(12);
 90             y1 = random.nextInt(height);
 91             y2 = random.nextInt(12);
 92             graphics.drawLine(x1, y1, x1 + x2, x2 + y2);
 93         }
 94 
 95         // 将上面图片输出到浏览器 ImageIO
 96         graphics.dispose();// 释放资源
 97         ImageIO.write(bufferedImage, "jpg", response.getOutputStream());
 98 
 99     }
100 
101 
102     public void doPost(HttpServletRequest request, HttpServletResponse response)
103             throws ServletException, IOException {
104         doGet(request, response);
105     }
106 
107     /**
108      * 取其某一范围的color
109      * 
110      * @param fc
111      *            int 范围参数1
112      * @param bc
113      *            int 范围参数2
114      * @return Color
115      */
116     private Color getRandColor(int fc, int bc) {
117         // 取其随机颜色
118         Random random = new Random();
119         if (fc > 255) {
120             fc = 255;
121         }
122         if (bc > 255) {
123             bc = 255;
124         }
125         int r = fc + random.nextInt(bc - fc);
126         int g = fc + random.nextInt(bc - fc);
127         int b = fc + random.nextInt(bc - fc);
128         return new Color(r, g, b);
129     }
130 
131 }

View Code

loginServlet

 1 package com.imooc.web.servlet;
 2 
 3 import java.io.IOException;
 4 import java.util.List;
 5 
 6 import javax.servlet.ServletException;
 7 import javax.servlet.annotation.WebServlet;
 8 import javax.servlet.http.HttpServlet;
 9 import javax.servlet.http.HttpServletRequest;
10 import javax.servlet.http.HttpServletResponse;
11 
12 import com.imooc.domain.User;
13 import com.imooc.service.UserService;
14 import com.imooc.service.impl.UserServiceImpl;
15 
16 @WebServlet("/LoginServlet")
17 public class LoginServlet extends HttpServlet {
18     private static final long serialVersionUID = 1L;
19 
20     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
21         // 完成验证码的校验:
22         // 获得session中保存的验证码的信息
23         String code1 = (String)request.getSession().getAttribute("checkCode");
24         // 接收前台表单提交的验证码的信息
25         String code2 = request.getParameter("checkCode");
26         if(code2==null || !code2.equalsIgnoreCase(code1)){
27             request.setAttribute("msg", "验证码输入不正确!");
28             request.getRequestDispatcher("/login.jsp").forward(request, response);
29             return;
30         }
31         
32         // 接收数据:
33         String username = request.getParameter("username");
34         String password = request.getParameter("password");
35         // 封装数据:
36         User user = new User();
37         user.setUsername(username);
38         user.setPassword(password);
39         // 处理数据:完成登陆.
40         UserService userService = new UserServiceImpl();
41         // 获得用户列表的集合:
42         List<User> userList = (List<User>)getServletContext().getAttribute("userList");
43         User existUser = userService.login(userList,user);
44         // 显示结果:
45         if(existUser == null){
46             // 登录失败
47             request.setAttribute("msg", "用户名或密码错误!");
48             request.getRequestDispatcher("/login.jsp").forward(request, response);
49         }else{
50             // 登录成功
51             // 将用户信息保存:
52             request.getSession().setAttribute("existUser", existUser);
53             response.sendRedirect(request.getContextPath()+"/index.jsp");
54         }
55     }
56 
57     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
58         doGet(request, response);
59     }
60 
61 }

View Code

Kaptcha验证码的介绍及入门

上面我们自己编写的验证码代码有一定的局限性,当验证码的样式,比如宽高等需要改变时,得更改相应的源代码,不是很方便

这时我们可以用第三方的验证码工具,如Kaptcha

首先我们要将Kaptcha的jar包引入到工程中

然后在web.xml中进行相应的配置

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
 3  
 4  <servlet>
 5      <servlet-name>KaptchaServlet</servlet-name>
 6      <servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class>
 7  
 8      <!-- 修改随机的字母或数字的长度 -->
 9      <init-param>
10          <param-name>kaptcha.textproducer.char.length</param-name>
11          <param-value>4</param-value>
12      </init-param>
13      
14      <!-- 修改字体大小 -->
15      <init-param>
16          <param-name>kaptcha.textproducer.font.size</param-name>
17          <param-value>25</param-value>
18      </init-param>
19      <init-param>
20          <param-name>kaptcha.textproducer.char.space</param-name>
21          <param-value>10</param-value>
22      </init-param>
23      
24      <!-- 修改图片的宽高 -->
25      <init-param>
26          <param-name>kaptcha.image.width</param-name>
27          <param-value>120</param-value>
28      </init-param>
29      <init-param>
30          <param-name>kaptcha.image.height</param-name>
31          <param-value>30</param-value>
32      </init-param>
33  </servlet>
34  
35  <servlet-mapping>
36      <servlet-name>KaptchaServlet</servlet-name>
37      <url-pattern>/KaptchaServlet</url-pattern>
38  </servlet-mapping>
39  
40  
41   <welcome-file-list>
42     <welcome-file>index.html</welcome-file>
43     <welcome-file>index.htm</welcome-file>
44     <welcome-file>index.jsp</welcome-file>
45     <welcome-file>default.html</welcome-file>
46     <welcome-file>default.htm</welcome-file>
47     <welcome-file>default.jsp</welcome-file>
48   </welcome-file-list>
49 </web-app>

View Code

配置参数介绍

配置前

配置后

Kaptcha验证码的校验

1 // 获得session中保存的验证码的信息
2  String code1 = (String)request.getSession().getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
3

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原文地址：https://www.cnblogs.com/superjishere/p/12680990.html