使用开源工具制作网页验证码的方法
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> <imgalt="random"src="randomcode.jpg"onclick="changeR(this)"style="cursor:pointer;"> <formaction="check.jsp"> <inputtype="text"name="r"> <inputtype="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(andoptionalalpha)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）
importcom.google.code.kaptcha.text.TextProducer;
importcom.google.code.kaptcha.util.Configurable;
importjava.util.Random;
publicclassChineseTextextendsConfigurableimplementsTextProducer{
publicStringgetText(){
intlength=getConfig().getTextProducerCharLength();
StringfinalWord="",firstWord="";
inttempInt=0;
String[]array={"0","1","2","3","4","5","6","7","8","9",
"a","b","c","d","e","f"};
Randomrand=newRandom();
for(inti=0;i<length;i++){
switch(rand.nextInt(array.length)){
case1:
tempInt=rand.nextInt(26)+65;
firstWord=String.valueOf((char)tempInt);
break;
case2:
intr1,
r2,
r3,
r4;
StringstrH,
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;
}elseif(r3==15){
r4=rand.nextInt(15);
}else{
r4=rand.nextInt(16);
}
strH=array[r1]+array[r2];
strL=array[r3]+array[r4];
byte[]bytes=newbyte[2];
bytes[0]=(byte)(Integer.parseInt(strH,16));
bytes[1]=(byte)(Integer.parseInt(strL,16));
firstWord=newString(bytes);
break;
default:
tempInt=rand.nextInt(10)+48;
firstWord=String.valueOf((char)tempInt);
break;
}
finalWord+=firstWord;
}
returnfinalWord;
}
}
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]viewplaincopy
<body>
<%
//检查是否是正确的验证码
Stringk=(String)session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
Stringstr=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
importcom.google.code.kaptcha.Producer;
importcom.google.code.kaptcha.util.Config;
importjava.awt.image.BufferedImage;
importjava.io.IOException;
importjava.util.Enumeration;
importjava.util.Properties;
importjavax.imageio.ImageIO;
importjavax.servlet.Servlet;
importjavax.servlet.ServletConfig;
importjavax.servlet.ServletException;
importjavax.servlet.ServletOutputStream;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importjavax.servlet.http.HttpSession;
publicclassKaptchaServletextendsHttpServletimplementsServlet{
privatePropertiesprops;
privateProducerkaptchaProducer;
privateStringsessionKeyValue;
publicKaptchaServlet(){
this.props=newProperties();
this.kaptchaProducer=null;
this.sessionKeyValue=null;
}
publicvoidinit(ServletConfigconf)throwsServletException{
super.init(conf);
ImageIO.setUseCache(false);
EnumerationinitParams=conf.getInitParameterNames();
while(initParams.hasMoreElements()){
Stringkey=(String)initParams.nextElement();
Stringvalue=conf.getInitParameter(key);
this.props.put(key,value);
}
Configconfig=newConfig(this.props);
this.kaptchaProducer=config.getProducerImpl();
this.sessionKeyValue=config.getSessionKey();
}
publicvoiddoGet(HttpServletRequestreq,HttpServletResponseresp)
throwsServletException,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");
StringcapText=this.kaptchaProducer.createText();
Strings1=capText.substring(0,1);
Strings2=capText.substring(1,2);
intr=Integer.valueOf(s1).intValue()+Integer.valueOf(s2).intValue();
req.getSession().setAttribute(this.sessionKeyValue,String.valueOf(r));
BufferedImagebi=this.kaptchaProducer.createImage(s1+"+"+s2+"=?");
ServletOutputStreamout=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毛票票网站的支持！