jcaptcha验证码使用（一）

jcaptcha使用默认样式生成的验证码比较难以识别，所以需要自定义验证码的样式，包括，背景色、背景大小、字体、字体大小、生成的字符数等。相对与kaptcha比较复杂。

创建一个JavaWeb工程，引入相关依赖jar包

创建一个jcaptcha单例的Service类，这里是设置验证码样式的关键部分

package cn.util;

import java.awt.Font;

import com.octo.captcha.CaptchaFactory;
import com.octo.captcha.component.image.backgroundgenerator.UniColorBackgroundGenerator;
import com.octo.captcha.component.image.color.RandomRangeColorGenerator;
import com.octo.captcha.component.image.fontgenerator.RandomFontGenerator;
import com.octo.captcha.component.image.textpaster.RandomTextPaster;
import com.octo.captcha.component.image.wordtoimage.ComposedWordToImage;
import com.octo.captcha.component.word.FileDictionary;
import com.octo.captcha.component.word.wordgenerator.ComposeDictionaryWordGenerator;
import com.octo.captcha.engine.GenericCaptchaEngine;
import com.octo.captcha.image.gimpy.GimpyFactory;
import com.octo.captcha.service.image.ImageCaptchaService;
import com.octo.captcha.service.multitype.GenericManageableCaptchaService;
 
public class CaptchaServiceSingleton {
    private static ImageCaptchaService service = null;
 
    public static ImageCaptchaService getService(){
        if(service == null)
            service = generatorCaptchaService();
        return service;
    }
    /**
     * 根据SpringBean的配置文件编写的代码实现
     * */
    public static ImageCaptchaService generatorCaptchaService(){
        //生成随机颜色，参数分别表示RGBA的取值范围
        RandomRangeColorGenerator textColor = new RandomRangeColorGenerator(new int[]{0,255},new int[]{0,180},new int[]{0,210},new int[]{255,255});
        //随机文字多少和颜色，参数1和2表示最少生成多少个文字和最多生成多少个
        RandomTextPaster randomTextPaster = new RandomTextPaster(4, 5, textColor,true);
        //生成背景的大小这里是宽85高40的图片，也可以设置背景颜色和随机背景颜色，这里使用默认的白色
        UniColorBackgroundGenerator colorbgGen = new UniColorBackgroundGenerator(85,40);
        //随机生成的字体大小和字体类型，参数1和2表示最小和最大的字体大小，第三个表示随机的字体
        RandomFontGenerator randomFontGenerator = new RandomFontGenerator(20, 25, new Font[]{new Font("Arial", 0, 10),new Font("Tahoma",0,10)});
        //结合上面的对象构件一个从文本生成图片的对象
        ComposedWordToImage cwti = new ComposedWordToImage(randomFontGenerator,colorbgGen,randomTextPaster);
        //随机文本的字典，这里是使用jcaptcha-1.0-all.jar中的文本字典，字典名称为toddlist.properties
        ComposeDictionaryWordGenerator cdwg = new ComposeDictionaryWordGenerator(new FileDictionary("toddlist"));
 
        GimpyFactory gf = new GimpyFactory(cdwg, cwti);
 
        GenericCaptchaEngine gce = new GenericCaptchaEngine(new CaptchaFactory[]{gf});
        //返回一个Service对象，这里180是验证码存在的时间，单位是秒，200000是最大存储大小
        return new GenericManageableCaptchaService(gce,180,200000,75000);
    }
}

创建一个生成验证码的Servlet

package cn.servlet;

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
 
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

import cn.util.CaptchaServiceSingleton;
 
public class CustomServlet extends HttpServlet {
 
    private static final long serialVersionUID = 169310818225761427L;
     
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        byte[] captChallengeAsJpeg = null;
         
        ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
         
        String captchaId = req.getSession().getId();
        BufferedImage challenge = CaptchaServiceSingleton.getService().getImageChallengeForID(captchaId,req.getLocale());
         
        JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(jpegOutputStream);
        jpegEncoder.encode(challenge);
         
        captChallengeAsJpeg = jpegOutputStream.toByteArray();
         
         resp.setHeader("Cache-Control", "no-store");
         resp.setHeader("Pragma", "no-cache");
         resp.setDateHeader("Expires", 0);
         resp.setContentType("image/jpeg");
          
         ServletOutputStream respOutputStream = resp.getOutputStream();
         respOutputStream.write(captChallengeAsJpeg);
         respOutputStream.flush();
         respOutputStream.close();
    }
}

在web.xml中注册这个Servlet

<servlet>
    <servlet-name>generateValidateCode</servlet-name>
    <servlet-class>cn.servlet.CustomServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>generateValidateCode</servlet-name>
    <url-pattern>/cgvc</url-pattern>
</servlet-mapping>

创建html页面，引入jquery.js文件

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<script type="text/javascript" src="statics/js/jquery-1.8.3.min.js"></script>
<script type="text/javascript">
    //验证码刷新功能
    function refreshCaptcha() {
        //Math.floor();向下取整
        //jQuery效果，fadeIn() 方法使用淡入效果来显示被选元素，假如该元素是隐藏的。
        $('#vcode').hide().attr(
            'src',
            'cgvc?'+ Math.floor(Math.random() * 100)).fadeIn();
    }
</script>
<body>
    <form action="valiServlet" method="post">
        <input type="text" name="customgvc">
        <img onclick="refreshCaptcha()" id="vcode" title="点击更换" alt="验证图片" style="vertical-align: middle;" src="cgvc" height="30" width="80">
        <input type="submit" value="提交">
    </form>
</body>
</html>

编写一个验证Servlet并在web.xml中注册。（success.html和fail.html就不创建了）

package cn.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cn.util.CaptchaServiceSingleton;
 
public class ValidateServlet extends HttpServlet {
 
    private static final long serialVersionUID = -7173743572400866269L;
     
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        String captchaId = req.getSession().getId();
         
        String validateCode = req.getParameter("customgvc");
         
        boolean validateResult = CaptchaServiceSingleton.getService().validateResponseForID(captchaId, validateCode);
        if(validateResult)
            resp.sendRedirect("success.html");
        else
            resp.sendRedirect("fail.html");
    }
}

<servlet>
    <servlet-name>validatServlet</servlet-name>
    <servlet-class>cn.servlet.ValidateServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>validatServlet</servlet-name>
    <url-pattern>/valiServlet</url-pattern>
</servlet-mapping>

输入验证码点击提交，看是否可以验证通过，如果一切正常的话Session中的和提交的是一致的