使用开源工具制作网页验证码的方法

站长资源 2024/11/25 佚名
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开发工具：eclipse、kaptcha-2.3.jar包。
一、创建Web项目；
二、新建一个Jsp页面（内容有，一个文本框，一个图片容器，一个提交按钮)
<body> 
<img alt="random" src="/UploadFiles/2021-04-02/randomcode.jpg">

三、可以看出图片验证码来源（src=“randomcode.jpg”）需配置Web.xml文件。（交给Servlet（该servlet在kaptcha-2.3.jar）处理）


<servlet> 
<servlet-name>Kaptcha</servlet-name> 
<servlet-class>com.google.code.kaptcha.servlet.KaptchaServlet</servlet-class> 
</servlet> 
<servlet-mapping> 
<servlet-name>Kaptcha</servlet-name> 
<url-pattern>/randomcode.jpg</url-pattern> 
</servlet-mapping>


四、由于需要kaptcha-2.3.jar包，所以将下载好的jar包导入在lib中。（复制黏贴即可）
其他：
一、网页验证码的属性
（一）添加边框


<servlet> 
<init-param> 
<description>图片边框，合法值：yes , no</description> 
<param-name>kaptcha.border</param-name> 
<param-value>yes</param-value> <!-- yes 或者 no--> 
</init-param> 
</servlet>


（二）边框颜色


<init-param> 
<description> 
边框颜色，合法值： r,g,b (and optional alpha) 或者white,black,blue. 
</description> 
<param-name>kaptcha.border.color</param-name> 
<param-value>black</param-value> 
</init-param>


（三）边框厚度


<init-param> 
<description>边框厚度，合法值：>大于0 </description> 
<param-name>kaptcha.border.thickness</param-name> 
<param-value>1</param-value> 
</init-param>


（四）图片宽度


<init-param> 
<description>图片宽 200</description> 
<param-name>kaptcha.image.width</param-name> 
<param-value>200</param-value> 
</init-param>


（五）图片高度


<init-param> 
<description>图片高 50</description> 
<param-name>kaptcha.image.height</param-name> 
<param-value>50</param-value> 
</init-param>


（六）验证码集合


<init-param> 
<description>文本集合，验证码值从此集合中获取</description> 
<param-name>kaptcha.textproducer.char.string</param-name> 
<param-value>1234567890</param-value> <!--纯数字 --> 
//<param-value>abcde2345678gfynmnpwx</param-value> <!-- 文字加英文--> 
</init-param>


（七）验证码长度


<init-param> 
<description>验证码长度 默认是5 </description> 
<param-name>kaptcha.textproducer.char.length</param-name> 
<param-value>2</param-value> 
</init-param>


（八）字体


<init-param> 
<description>字体 Arial, Courier</description> 
<param-name>kaptcha.textproducer.font.names</param-name> 
<param-value>Arial, Courier</param-value> 
</init-param>


（九）字体大小


<init-param> 
<description>字体大小 40px.</description> 
<param-name>kaptcha.textproducer.font.size</param-name> 
<param-value>40</param-value> 
</init-param>


（十）字体颜色


<init-param> 
<description> 
字体颜色，合法值： r,g,b 或者 white,black,blue. 
</description> 
<param-name>kaptcha.textproducer.font.color</param-name> 
<param-value>black</param-value> 
</init-param>


（十一）每个验证码之间的间隔


<init-param> 
<description>文字间隔 2</description> 
<param-name>kaptcha.textproducer.char.space</param-name> 
<param-value>2</param-value> 
</init-param>


（十二）干扰实现


<init-param> 
<description>干扰实现类</description> 
<param-name>kaptcha.noise.impl</param-name> 
<param-value> 
<!-- com.google.code.kaptcha.impl.NoNoise --> 
com.google.code.kaptcha.impl.DefaultNoise 
</param-value> 
</init-param>


（十三）干扰颜色


<init-param> 
<description> 
干扰颜色，合法值： r,g,b 或者 white,black,blue. 
</description> 
<param-name>kaptcha.noise.color</param-name> 
<param-value>black</param-value> 
</init-param>


（十四）背景样式


<init-param> 
<description> 
图片样式： 水纹com.google.code.kaptcha.impl.WaterRipple 
鱼眼com.google.code.kaptcha.impl.FishEyeGimpy 
阴影com.google.code.kaptcha.impl.ShadowGimpy 
</description> 
<param-name>kaptcha.obscurificator.impl</param-name> 
<param-value> 
com.google.code.kaptcha.impl.WaterRipple 
</param-value> 
</init-param>


（十五）背景实现类


<init-param> 
<description>背景实现类</description> 
<param-name>kaptcha.background.impl</param-name> 
<param-value> 
com.google.code.kaptcha.impl.DefaultBackground 
</param-value> 
</init-param>


（十六）背景渐变颜色


<init-param> 
<description>背景颜色渐变，开始颜色</description> 
<param-name>kaptcha.background.clear.from</param-name> 
<param-value>green</param-value> 
</init-param> 
<init-param> 
<description>背景颜色渐变，结束颜色</description> 
<param-name>kaptcha.background.clear.to</param-name> 
<param-value>white</param-value> 
</init-param>


（十七）文字渲染器


<init-param> 
<description> 文字渲染器 </description> 
<param-name>kaptcha.word.impl</param-name> 
<param-value> 
com.google.code.kaptcha.text.impl.DefaultWordRenderer
</param-value> 
</init-param>


（十八）图片的验证码会保存在Session中，其中的值为


<init-param> 
<description> session中存放验证码的key键 </description> 
<param-name>kaptcha.session.key</param-name> 
<param-value>KAPTCHA_SESSION_KEY</param-value> 
</init-param>


（十九）图片实现类别


<init-param> 
<description>图片实现类</description> 
<param-name>kaptcha.producer.impl</param-name> 
<param-value> 
com.google.code.kaptcha.impl.DefaultKaptcha 
</param-value> 
</init-param>


（二十）文本实现类（可通过重写该类来实现验证码为中文）


<init-param> 
<description>文本实现类</description> 
<param-name>kaptcha.textproducer.impl</param-name> 
<param-value> 
com.google.code.kaptcha.text.impl.DefaultTextCreator 
</param-value> 
</init-param>


重写文本实现类，实现验证码为中文：
1.创建一个类别，继承Configurable 实现TextProducer（在jar包中）


import com.google.code.kaptcha.text.TextProducer; 
import com.google.code.kaptcha.util.Configurable; 
import java.util.Random; 
public class ChineseText extends Configurable implements TextProducer { 
public String getText() { 
int length = getConfig().getTextProducerCharLength(); 
String finalWord = "", firstWord = ""; 
int tempInt = 0; 
String[] array = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", 
"a", "b", "c", "d", "e", "f" }; 
Random rand = new Random(); 
for (int i = 0; i < length; i++) { 
switch (rand.nextInt(array.length)) { 
case 1: 
tempInt = rand.nextInt(26) + 65; 
firstWord = String.valueOf((char) tempInt); 
break; 
case 2: 
int r1, 
r2, 
r3, 
r4; 
String strH, 
strL;// high&low 
r1 = rand.nextInt(3) + 11; // 前闭后开[11,14) 
if (r1 == 13) { 
r2 = rand.nextInt(7); 
} else { 
r2 = rand.nextInt(16); 
} 
r3 = rand.nextInt(6) + 10; 
if (r3 == 10) { 
r4 = rand.nextInt(15) + 1; 
} else if (r3 == 15) { 
r4 = rand.nextInt(15); 
} else { 
r4 = rand.nextInt(16); 
} 
strH = array[r1] + array[r2]; 
strL = array[r3] + array[r4]; 
byte[] bytes = new byte[2]; 
bytes[0] = (byte) (Integer.parseInt(strH, 16)); 
bytes[1] = (byte) (Integer.parseInt(strL, 16)); 
firstWord = new String(bytes); 
break; 
default: 
tempInt = rand.nextInt(10) + 48; 
firstWord = String.valueOf((char) tempInt); 
break; 
} 
finalWord += firstWord; 
} 
return finalWord; 
} 
}


2.修改Web.xml配置


<init-param> 
<description>文本实现类</description> 
<param-name>kaptcha.textproducer.impl</param-name> 
<param-value> 
ChineseText 
</param-value> 
</init-param> 
五、验证码的校验（本文是利用check.jsp来校验的）保存在Session中，其中的键值为（第十八个属性）
[html] view plain copy
<body> 
<% 
// 检查是否是正确的验证码 
String k = (String) session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY); 
String str = request.getParameter("r"); 
if (k.equals(str)) 
out.print("true"); 
out.print(k + "---" + str); 
%> 
</body>


六、扩展（加法验证码的实现）
1.重写KaptchaServlet类


import com.google.code.kaptcha.Producer; 
import com.google.code.kaptcha.util.Config; 
import java.awt.image.BufferedImage; 
import java.io.IOException; 
import java.util.Enumeration; 
import java.util.Properties; 
import javax.imageio.ImageIO; 
import javax.servlet.Servlet; 
import javax.servlet.ServletConfig; 
import javax.servlet.ServletException; 
import javax.servlet.ServletOutputStream; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 
import javax.servlet.http.HttpSession; 
public class KaptchaServlet extends HttpServlet implements Servlet { 
private Properties props; 
private Producer kaptchaProducer; 
private String sessionKeyValue; 
public KaptchaServlet() { 
this.props = new Properties(); 
this.kaptchaProducer = null; 
this.sessionKeyValue = null; 
} 
public void init(ServletConfig conf) throws ServletException { 
super.init(conf); 
ImageIO.setUseCache(false); 
Enumeration initParams = conf.getInitParameterNames(); 
while (initParams.hasMoreElements()) { 
String key = (String) initParams.nextElement(); 
String value = conf.getInitParameter(key); 
this.props.put(key, value); 
} 
Config config = new Config(this.props); 
this.kaptchaProducer = config.getProducerImpl(); 
this.sessionKeyValue = config.getSessionKey(); 
} 
public void doGet(HttpServletRequest req, HttpServletResponse resp) 
throws ServletException, IOException { 
resp.setDateHeader("Expires", 0L); 
resp.setHeader("Cache-Control", "no-store, no-cache, must-revalidate"); 
resp.addHeader("Cache-Control", "post-check=0, pre-check=0"); 
resp.setHeader("Pragma", "no-cache"); 
resp.setContentType("image/jpeg"); 
String capText = this.kaptchaProducer.createText(); 
String s1 = capText.substring(0, 1); 
String s2 = capText.substring(1, 2); 
int r = Integer.valueOf(s1).intValue() + Integer.valueOf(s2).intValue(); 
req.getSession().setAttribute(this.sessionKeyValue, String.valueOf(r)); 
BufferedImage bi = this.kaptchaProducer.createImage(s1+"+"+s2+"="); 
ServletOutputStream out = resp.getOutputStream(); 
ImageIO.write(bi, "jpg", out); 
try { 
out.flush(); 
} finally { 
out.close(); 
} 
} 
}


2.修改配置文件


<servlet> 
<servlet-name>Kaptcha</servlet-name> 
<servlet-class>KaptchaServlet</servlet-class> 
</servlet>


以上所述是小编给大家介绍的使用开源工具制作网页验证码的方法，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对网站的支持！