转载该文章的原因是为了保存利用命令行jar包上传到本地库的方法，哈哈。。
一：Kaptcha介绍
简单介绍：
kaptcha 是一个扩展自 simplecaptcha 的验证码库，在 Java 编程中 是一个非常实用的验证码生成工具。我们可以利用这个工具生成各种样式的验证码，因为它是可配置的，我们可以根据需求定制。
工作原理：
kaptcha 的工作原理是调用 com.google.code.kaptcha.servlet.KaptchaServlet ，生成一个验证码图片，响应到客户端，同时将生成的真是的验证码字符串放到 HttpSession 中。
使用kaptcha可以方便的配置：
- 验证码的字体
- 验证码字体的大小
- 验证码字体的字体颜色
- 验证码内容的范围(数字，字母，中文汉字！)
- 验证码图片的大小，边框，边框粗细，边框颜色
- 验证码的干扰线(可以自己继承com.google.code.kaptcha.NoiseProducer写一个自定义的干扰线)
- 验证码的样式(鱼眼样式、3D、普通模糊……当然也可以继承com.google.code.kaptcha.GimpyEngine自定义样式)
二：使用Kaptcha生成验证码
由于中央库里没有该jar包，所以需要我们用命令添加到本地库
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首先下载jar包
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安装到本地库
解压下载好的源码到f盘，利用命令添加到本地库
F:\kaptcha-2.3.2>mvn install:install-file -DgroupId=com.google.code -DartifactId=kaptcha -Dversion=2.3.2 -Dfile=F:\kaptcha-2.3.2\kaptcha-2.3.2.jar -Dpackaging=jar -DgeneratePom=true
pom.xml中的配置如下，注意要和上面的groupId、artifactId和version保持一致
1 <dependency> 2 <groupId>com.google.code</groupId> 3 <artifactId>kaptcha</artifactId> 4 <version>2.3.2</version> 5 </dependency>
3. 开始写代码
ChineseText.java
1public class ChineseText extends Configurable implements TextProducer { 2 3 public String getText() { 4 int length = getConfig().getTextProducerCharLength(); 5 //char[] charS = getConfig().getTextProducerCharString(); 6 7 String[] s = new String[]{"验","证","码","测","试"}; 8 9 Random rand = new Random(); 10 StringBuffer sb = new StringBuffer(); 11 for(int i = 0; i < length; i++){ 12 int ind = rand.nextInt(s.length); 13 sb.append(s[ind]); 14 } 15 return sb.toString(); 16 } 17 /** 18 * 中午实例 19 * @return 20 */ 21 public String getText1() { 22 int length = getConfig().getTextProducerCharLength(); 23 String finalWord = "", firstWord = ""; 24 int tempInt = 0; 25 String[] array = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", 26 "a", "b", "c", "d", "e", "f","g","h","i","j","k","l","m","n", 27 "o","p","q","r","s","t","u","v","w","x","y","z" }; 28 29 Random rand = new Random(); 30 31 for (int i = 0; i < length; i++) { 32 switch (rand.nextInt(array.length)) { 33 case 1: 34 tempInt = rand.nextInt(26) + 65; 35 firstWord = String.valueOf((char) tempInt); 36 break; 37 case 2: 38 int r1, 39 r2, 40 r3, 41 r4; 42 String strH, 43 strL;// high&low 44 r1 = rand.nextInt(3) + 11; // 前闭后开[11,14) 45 if (r1 == 13) { 46 r2 = rand.nextInt(7); 47 } else { 48 r2 = rand.nextInt(16); 49 } 50 51 r3 = rand.nextInt(6) + 10; 52 if (r3 == 10) { 53 r4 = rand.nextInt(15) + 1; 54 } else if (r3 == 15) { 55 r4 = rand.nextInt(15); 56 } else { 57 r4 = rand.nextInt(16); 58 } 59 60 strH = array[r1] + array[r2]; 61 strL = array[r3] + array[r4]; 62 63 byte[] bytes = new byte[2]; 64 bytes[0] = (byte) (Integer.parseInt(strH, 16)); 65 bytes[1] = (byte) (Integer.parseInt(strL, 16)); 66 67 firstWord = new String(bytes); 68 break; 69 default: 70 tempInt = rand.nextInt(10) + 48; 71 firstWord = String.valueOf((char) tempInt); 72 break; 73 } 74 finalWord += firstWord; 75 } 76 return finalWord; 77 } 78}
生成验证码的servlet
1public class KaptchaServlet extends HttpServlet implements Servlet { 2 /** 3 * 4 */ 5 private static final long serialVersionUID = 1L; 6 private Properties props; 7 private Producer kaptchaProducer; 8 private String sessionKeyValue; 9 10 public KaptchaServlet() { 11 this.props = new Properties(); 12 13 this.kaptchaProducer = null; 14 15 this.sessionKeyValue = null; 16 } 17 18 public void init(ServletConfig conf) throws ServletException { 19 super.init(conf); 20 21 ImageIO.setUseCache(false); 22 23 @SuppressWarnings("rawtypes") 24 Enumeration initParams = conf.getInitParameterNames(); 25 while (initParams.hasMoreElements()) { 26 String key = (String) initParams.nextElement(); 27 String value = conf.getInitParameter(key); 28 this.props.put(key, value); 29 } 30 31 Config config = new Config(this.props); 32 this.kaptchaProducer = config.getProducerImpl(); 33 this.sessionKeyValue = config.getSessionKey(); 34 } 35 36 public void doGet(HttpServletRequest req, HttpServletResponse resp) 37 throws ServletException, IOException { 38 resp.setDateHeader("Expires", 0L); 39 40 resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate"); 41 42 resp.addHeader("Cache-Control", "post-check=0, pre-check=0"); 43 44 resp.setHeader("Pragma", "no-cache"); 45 46 resp.setContentType("image/jpeg"); 47 48 String capText = this.kaptchaProducer.createText(); 49 String s1 = capText.substring(0, 1); 50 String s2 = capText.substring(1, 2); 51 int r = Integer.valueOf(s1).intValue() + Integer.valueOf(s2).intValue(); 52 53 req.getSession().setAttribute(this.sessionKeyValue, String.valueOf(r)); 54 55 BufferedImage bi = this.kaptchaProducer.createImage(s1+"+"+s2+"=?"); 56 57 ServletOutputStream out = resp.getOutputStream(); 58 59 ImageIO.write(bi, "jpg", out); 60 try { 61 out.flush(); 62 } finally { 63 out.close(); 64 } 65 } 66}
web.xml中的配置
1<?xml version="1.0" encoding="UTF-8"?> 2<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 5 http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> 6 7 8 <!-- 登陆验证码Kaptcha 2--> 9 <servlet> 10 <servlet-name>Kaptcha</servlet-name> 11 <servlet-class> 12 com.verify.kaptcha.KaptchaServlet 13 </servlet-class> 14 <init-param> 15 <description>图片边框，合法值：yes , no</description> 16 <param-name>kaptcha.border</param-name> 17 <param-value>yes</param-value> 18 </init-param> 19 <init-param> 20 <description> 21 边框颜色，合法值： r,g,b (and optional alpha) 或者 22 white,black,blue. 23 </description> 24 <param-name>kaptcha.border.color</param-name> 25 <param-value>black</param-value> 26 </init-param> 27 <init-param> 28 <description>边框厚度，合法值：>0</description> 29 <param-name>kaptcha.border.thickness</param-name> 30 <param-value>1</param-value> 31 </init-param> 32 <init-param> 33 <description>图片宽 200</description> 34 <param-name>kaptcha.image.width</param-name> 35 <param-value>200</param-value> 36 </init-param> 37 <init-param> 38 <description>图片高 50</description> 39 <param-name>kaptcha.image.height</param-name> 40 <param-value>50</param-value> 41 </init-param> 42 <init-param> 43 <description>图片实现类</description> 44 <param-name>kaptcha.producer.impl</param-name> 45 <param-value> 46 com.google.code.kaptcha.impl.DefaultKaptcha 47 </param-value> 48 </init-param> 49 <init-param> 50 <description>文本实现类</description> 51 <param-name>kaptcha.textproducer.impl</param-name> 52 <param-value> 53 com.google.code.kaptcha.text.impl.DefaultTextCreator 54 </param-value> 55 </init-param> 56 <init-param> 57 <description>文本集合，验证码值从此集合中获取</description> 58 <param-name>kaptcha.textproducer.char.string</param-name> 59 <param-value>1234567890</param-value> 60 </init-param> 61 <init-param> 62 <description>验证码长度 5</description> 63 <param-name>kaptcha.textproducer.char.length</param-name> 64 <param-value>2</param-value> 65 </init-param> 66 <init-param> 67 <description>字体 Arial, Courier</description> 68 <param-name>kaptcha.textproducer.font.names</param-name> 69 <param-value>Arial, Courier</param-value> 70 </init-param> 71 <init-param> 72 <description>字体大小 40px.</description> 73 <param-name>kaptcha.textproducer.font.size</param-name> 74 <param-value>40</param-value> 75 </init-param> 76 <init-param> 77 <description> 78 字体颜色，合法值： r,g,b 或者 white,black,blue. 79 </description> 80 <param-name>kaptcha.textproducer.font.color</param-name> 81 <param-value>black</param-value> 82 </init-param> 83 <init-param> 84 <description>文字间隔 2</description> 85 <param-name>kaptcha.textproducer.char.space</param-name> 86 <param-value>2</param-value> 87 </init-param> 88 <init-param> 89 <description>干扰实现类</description> 90 <param-name>kaptcha.noise.impl</param-name> 91 <param-value> 92 <!-- com.google.code.kaptcha.impl.NoNoise --> 93 com.google.code.kaptcha.impl.DefaultNoise 94 </param-value> 95 </init-param> 96 <init-param> 97 <description> 98 干扰颜色，合法值： r,g,b 或者 white,black,blue. 99 </description> 100 <param-name>kaptcha.noise.color</param-name> 101 <param-value>black</param-value> 102 </init-param> 103 <init-param> 104 <description> 105 图片样式： 水纹com.google.code.kaptcha.impl.WaterRipple 106 鱼眼com.google.code.kaptcha.impl.FishEyeGimpy 107 阴影com.google.code.kaptcha.impl.ShadowGimpy 108 </description> 109 <param-name>kaptcha.obscurificator.impl</param-name> 110 <param-value> 111 com.google.code.kaptcha.impl.WaterRipple 112 </param-value> 113 </init-param> 114 <init-param> 115 <description>背景实现类</description> 116 <param-name>kaptcha.background.impl</param-name> 117 <param-value> 118 com.google.code.kaptcha.impl.DefaultBackground 119 </param-value> 120 </init-param> 121 <init-param> 122 <description>背景颜色渐变，开始颜色</description> 123 <param-name>kaptcha.background.clear.from</param-name> 124 <param-value>green</param-value> 125 </init-param> 126 <init-param> 127 <description>背景颜色渐变，结束颜色</description> 128 <param-name>kaptcha.background.clear.to</param-name> 129 <param-value>white</param-value> 130 </init-param> 131 <init-param> 132 <description>文字渲染器</description> 133 <param-name>kaptcha.word.impl</param-name> 134 <param-value> 135 com.google.code.kaptcha.text.impl.DefaultWordRenderer 136 </param-value> 137 </init-param> 138 <init-param> 139 <description> 140 session中存放验证码的key键 141 </description> 142 <param-name>kaptcha.session.key</param-name> 143 <param-value>KAPTCHA_SESSION_KEY</param-value> 144 </init-param> 145 <init-param> 146 <description> 147 The date the kaptcha is generated is put into the 148 HttpSession. This is the key value for that item in the 149 session. 150 </description> 151 <param-name>kaptcha.session.date</param-name> 152 <param-value>KAPTCHA_SESSION_DATE</param-value> 153 </init-param> 154 </servlet> 155 <servlet-mapping> 156 <servlet-name>Kaptcha</servlet-name> 157 <url-pattern>/randomcode.jpg</url-pattern> 158 </servlet-mapping> 159 160 161 <welcome-file-list> 162 <welcome-file>index.jsp</welcome-file> 163 </welcome-file-list> 164</web-app>
验证码页面index.jsp
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>kaptcha生成验证码</title> 8<script type="text/javascript"> 9 function changeR(node){ 10 // 用于点击时产生不同的验证码 11 node.src = "randomcode.jpg?time="+new Date().getTime() ; 12 } 13</script> 14</head> 15<body> 16<div style="text-align: center;"> 17<h2>验证码之kaptcha</h2> 18<img alt="random" src="randomcode.jpg" onclick="changeR(this)" style="cursor: pointer;"><br/><br/> 19 <form action="checkCode.jsp"> 20 <input type="text" name="checkCode"> 21 <input type="submit" value="提交"> 22 </form> 23</div> 24</body> 25</html>
验证的页面checkCode.jsp
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>Kaptcha验证码验证</title> 8</head> 9<body> 10 <% 11 //从session中取服务器中的验证码 12 String kaptchaServer = (String)request.getSession().getAttribute 13 (com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY); 14 String kaptchaClient = request.getParameter("checkCode"); 15 out.print("<div style='text-align: center;'>"); 16 if (kaptchaServer.equals(kaptchaClient)) 17 out.print("<h2>verify success</h2>"); 18 else 19 out.println("<h2>verify fail</h2>"); 20 21 out.print("<h4>kaptchaServer===><span style='color:red;'>"+kaptchaServer+"</span>\tkaptchaClient===><span style='color:red;'>"+kaptchaClient+"</span></h4>"); 22 out.print("</div>"); 23 %> 24</body> 25</html>
下面来看看效果图
