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Servlet实现验证码图片（一）

Servlet实现数字字母验证码图片（一）：

生成验证码图片主要用到了一个BufferedImage类，如下：

1、引入jquery-1.10.2.js文件，创建verifyCode.jsp

 1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 2 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
 3 <html>
 4 <head>
 5 
 6 <title>Java验证码</title>
 7 </head>
 8 
 9 <body>
10     <table width="100%" border="0" cellspacing="0" cellpadding="0">
11         <tr>
12             <td width="100"></td>
13             <td width="100">验证码：</td>
14             <td width="150"><input id="veryCode" name="veryCode" type="text"
15                 class="yzm" value="" onmouseout="isRightCode()" /></td>
16             <td width="135"><img id="imgObj" alt="" src="${pageContext.request.contextPath}/DrawImage"
17                 onclick="changeImg()" /></td>
18             <td><a href="javascript:void(0);" onclick="changeImg()">看不清，换一张</a></td>
19             <td></td>
20         </tr>
21         <tr>
22             <td style="line-height: 38px; color: #FF0000; text-align: center;"
23                 colspan="4" id="info"></td>
24             <td></td>
25         </tr>
26     </table>
27 </body>
28 <script type="text/javascript"    src="js/jquery-1.10.2.js"></script>
29 <script type="text/javascript">
30         /** 
31          * 验证code-js 
32          */
33 
34         // 点击换一张验证码  
35         function changeImg() {
36             var imgSrc = $("#imgObj");
37             var src = imgSrc.attr("src");
38             //时间戳 ,为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳  
39             var timestamp = (new Date()).valueOf();
40             src =src +"?timestamp=" + timestamp;;
41             imgSrc.attr("src", src);
42             $("#info").html("");
43         }
44         // 验证码验证  
45         function isRightCode() {
46             var code = $("#veryCode").val();
47             alert("code="+code);  
48             code = "c=" + code;
49             $.ajax({
50                 type : "POST",
51                 url : "resultServlet",
52                 data : code,
53                 success :function callback(data) {// 验证以后处理提交信息或错误信息  
54                     if (data.toString() == 1) {
55                         $("#info").html("提示您：验证成功了！");
56                         return;
57                     } else {
58                         $("#info").html(data);
59                         return;
60                     }
61                 }
62             });
63         }
64 </script>
65 </html>

2.创建画图servlet，DrawImage.java

  1 package com.utils;
  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  * 生成随机验证码图片
 20  * 
 21  * @author huang
 22  * 
 23  */
 24 @WebServlet("/DrawImage")
 25 public class DrawImage extends HttpServlet {
 26     private static final long serialVersionUID = 1L;
 27     public static final int WIDTH = 120;
 28     public static final int HEIGHT = 30;
 29 
 30     // 在报java.lang.NoClassDefFoundError: Could not initialize class
 31     // javax.imageio.ImageIO错的时候加上这个很管用。
 32     static {
 33         ImageIO.scanForPlugins();
 34     }
 35 
 36     public void doGet(HttpServletRequest request, HttpServletResponse response)
 37             throws ServletException, IOException {
 38         this.doPost(request, response);
 39     }
 40 
 41     public void doPost(HttpServletRequest request, HttpServletResponse response)
 42             throws ServletException, IOException {
 43         request.setCharacterEncoding("utf-8");
 44         response.setContentType("text/html;charset=utf-8");
 45         // 创建缓存
 46         BufferedImage bi = new BufferedImage(WIDTH, HEIGHT,
 47                 BufferedImage.TYPE_INT_RGB);
 48         // 获得画布
 49         Graphics g = bi.getGraphics();
 50         // 设置背影色
 51         setBackGround(g);
 52         // 设置边框
 53         setBorder(g);
 54         // 画干扰线
 55         drawRandomLine(g);
 56         // 写随机数
 57         String random = drawRandomNum((Graphics2D) g);
 58         // 将随机汉字存在session中
 59         request.getSession().setAttribute("checkcode", random);
 60         // 将图形写给浏览器
 61         response.setContentType("image/jpeg");
 62         // 发头控制浏览器不要缓存
 63         response.setDateHeader("expries", -1);
 64         response.setHeader("Cache-Control", "no-cache");
 65         response.setHeader("Pragma", "no-cache");
 66         // 将图片写给浏览器
 67         ImageIO.write(bi, "jpg", response.getOutputStream());
 68     }
 69 
 70     /**
 71      * 设置背景色
 72      * 
 73      * @param g
 74      */
 75     private void setBackGround(Graphics g) {
 76         // 设置颜色
 77         g.setColor(new Color(249, 249, 249));
 78         // 填充区域
 79         g.fillRect(0, 0, WIDTH, HEIGHT);
 80 
 81     }
 82 
 83     /**
 84      * 设置边框
 85      * 
 86      * @param g
 87      */
 88     private void setBorder(Graphics g) {
 89         // 设置边框颜色
 90         // RGB
 91         g.setColor(new Color(210, 209, 205));
 92         // 边框区域
 93         g.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);
 94     }
 95 
 96     /**
 97      * 画随机线条
 98      * 
 99      * @param g
100      */
101     private void drawRandomLine(Graphics g) {
102         // 设置颜色
103         g.setColor(Color.GRAY);
104         // 设置线条个数并画线
105         for (int i = 0; i < 5; i++) {
106             int x1 = new Random().nextInt(WIDTH);
107             int y1 = new Random().nextInt(HEIGHT);
108             int x2 = new Random().nextInt(WIDTH);
109             int y2 = new Random().nextInt(HEIGHT);
110             g.drawLine(x1, y1, x2, y2);
111         }
112     }
113 
114     /**
115      * 画随机汉字
116      * 
117      * @param g
118      * @return
119      */
120     private String drawRandomNum(Graphics2D g) {
121         StringBuffer sb = new StringBuffer();
122         // 设置字体
123         g.setFont(new Font("宋体", Font.BOLD, 20));
124         // 准备常用汉字集
125         // String base =
126         // "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";
127         // String base =
128         // "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";
129         // 准备常用字符集
130         String base = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
131         int x = 5;
132         // 控制字数
133         for (int i = 0; i < 4; i++) {
134             // 生成0-255的随机数
135             int R = new Random().nextInt(256);
136             int G = new Random().nextInt(256);
137             int B = new Random().nextInt(256);
138             // 设置每个随机数的颜色
139             g.setColor(new Color(R, G, B));
140             // 设置字体旋转角度
141             int degree = new Random().nextInt() % 30;
142             // 截取汉字
143             String ch = base.charAt(new Random().nextInt(base.length())) + "";
144             sb.append(ch);
145             // 正向角度
146             g.rotate(degree * Math.PI / 180, x, 20);
147             g.drawString(ch, x, 20);
148             // 反向角度
149             g.rotate(-degree * Math.PI / 180, x, 20);
150             x += 30;
151         }
152         return sb.toString();
153     }
154 }

3.创建验证结果servlet，ResultServlet.java

 1 package com.utils;
 2 
 3 import java.io.IOException;  
 4 import java.io.PrintWriter;  
 5   
 6 
 7 import javax.servlet.ServletException;  
 8 import javax.servlet.annotation.WebServlet;
 9 import javax.servlet.http.HttpServlet;  
10 import javax.servlet.http.HttpServletRequest;  
11 import javax.servlet.http.HttpServletResponse;  
12   
13 /** 
14  * 结果验证Servlet 
15  * @author huang 
16  * 
17  */  
18 @WebServlet("/resultServlet")
19 public class ResultServlet extends HttpServlet {  
20   
21     /** 
22      *  
23      */  
24     private static final long serialVersionUID = 1L;  
25   
26     public void doGet(HttpServletRequest request, HttpServletResponse response)  
27             throws ServletException, IOException {  
28   
29         doPost(request, response);  
30     }  
31   
32     /**   
33      * 后台验证输入 
34      */  
35     public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {  
36         response.setContentType("text/html;charset=utf-8");  
37         String validateC = (String) request.getSession().getAttribute("checkcode");  
38         //从前台传来的用户输入的验证码  
39         String veryCode = request.getParameter("c");  
40         System.out.println("veryCode:"+veryCode);
41         PrintWriter out = response.getWriter();  
42         if (veryCode == null || "".equals(veryCode)) {  
43             out.println("请输入验证码！");  
44         } else {  
45 //          if (validateC.equals(veryCode)) {  
46             // 忽略大小写处理：
47             if (validateC.equalsIgnoreCase(veryCode)) {  
48                 out.println(1);  
49             } else {  
50                 out.println("验证码输入错误！");  
51             }  
52         }  
53         out.flush();  
54         out.close();  
55     }  
56   
57 }

4、结果

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原文地址：https://www.cnblogs.com/huangdabing/p/9181009.html