使用开源工具制作网页验证码的方法

编程学习 2021-07-04 20:01www.dzhlxh.cn编程入门
这篇文章主要介绍了使用开源工具制作网页验证码的方法的相关资料,非常不错,具有参考借鉴价值,需要的朋友可以参考下

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="randomcode.jpg" onclick="changeR(this)" style="cursor: pointer;"> 
<form action="check.jsp"> 
<input type="text" name="r"> 
<input type="submit" value="s"> 
</form> 
</body>

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>

以上所述是长沙网络推广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,长沙网络推广会及时回复大家的。在此也非常感谢大家对狼蚁SEO网站的支持!

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