验证码生成组件--JCaptcha的使用

以下为项目中所用代码，文笔有限，直接上代码。

所需jar包：

是否需要其他依赖包，不详

web.xml

<servlet>
     <servlet-name>Jcaptcha</servlet-name>
     <servlet-class>com.bkgd.cms.servlet.JcaptchaServlet</servlet-class>
</servlet>
<servlet-mapping>
     <servlet-name>Jcaptcha</servlet-name>
     <url-pattern>/captcha.svl</url-pattern>
</servlet-mapping>

需要一个服务类 生成Image

package com.bkgd.cms.servlet;

import java.awt.image.BufferedImage;
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 org.apache.commons.io.output.ByteArrayOutputStream;
import org.apache.log4j.Logger;
import com.octo.captcha.service.CaptchaServiceException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

@SuppressWarnings("serial")
public class JcaptchaServlet extends HttpServlet {
public static final String CAPTCHA_IMAGE_FORMAT = "jpeg";

private static final Logger log = Logger.getLogger(JcaptchaServlet.class);

@Override
public void init() throws ServletException {
}

/**
 * @step1 本方法使用Jcaptcha工具生成img图片，并输出到客户端
 * @step2 将来在用户提交的action中插入下面语句进行验证码的校验：Boolean isResponseCorrect =
 *        captchaService.validateResponseForID( captchaId, "");
 **/
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
byte[] captchaChallengeAsJpeg = null;
ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
try {
// 借助于HttpSession ID存储Captcha ID，开发者也可以借助于其他惟一值
String captchaId = request.getSession().getId();
// 获得GMailEngine使用的图片内容
BufferedImage challenge = JCaptchaServiceSingleton.getInstance().getImageChallengeForID(captchaId, request.getLocale());
// 输出JPEG格式
JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(jpegOutputStream);
jpegEncoder.encode(challenge);
} catch (IllegalArgumentException e) {
log.error(e);
response.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
} catch (CaptchaServiceException e) {
log.error(e);
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
return;
}
captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
response.setHeader("Cache-Control", "no-store");
response.setHeader("Pragma", "no-cache");
response.setDateHeader("Expires", 0);
// 输出JPEG图片
response.setContentType("image/jpeg");
ServletOutputStream responseOutputStream = response.getOutputStream();
responseOutputStream.write(captchaChallengeAsJpeg);
responseOutputStream.flush();
responseOutputStream.close();
}
}

JCaptchaServiceSingleton

package com.bkgd.cms.servlet;

import com.octo.captcha.service.captchastore.FastHashMapCaptchaStore;
import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;
import com.octo.captcha.service.image.ImageCaptchaService;

public class JCaptchaServiceSingleton {
private static ImageCaptchaService imageCaptchaService = new DefaultManageableImageCaptchaService(
new FastHashMapCaptchaStore(), new GMailEngine(), 180, 100000,
75000);

public static ImageCaptchaService getInstance() {
return imageCaptchaService;
}
}

验证码样式的图片引擎GMailEngine

package com.bkgd.cms.servlet;

import java.awt.Color;
import java.awt.Font;
import java.awt.image.ImageFilter;

import com.octo.captcha.component.image.backgroundgenerator.BackgroundGenerator;
import com.octo.captcha.component.image.backgroundgenerator.UniColorBackgroundGenerator;
import com.octo.captcha.component.image.color.RandomListColorGenerator;
import com.octo.captcha.component.image.deformation.ImageDeformation;
import com.octo.captcha.component.image.deformation.ImageDeformationByFilters;
import com.octo.captcha.component.image.fontgenerator.FontGenerator;
import com.octo.captcha.component.image.fontgenerator.RandomFontGenerator;
import com.octo.captcha.component.image.textpaster.DecoratedRandomTextPaster;
import com.octo.captcha.component.image.textpaster.TextPaster;
import com.octo.captcha.component.image.textpaster.textdecorator.TextDecorator;
import com.octo.captcha.component.image.wordtoimage.DeformedComposedWordToImage;
import com.octo.captcha.component.image.wordtoimage.WordToImage;
import com.octo.captcha.component.word.wordgenerator.RandomWordGenerator;
import com.octo.captcha.component.word.wordgenerator.WordGenerator;
import com.octo.captcha.engine.image.ListImageCaptchaEngine;
import com.octo.captcha.image.gimpy.GimpyFactory;

/**
 * 仿照JCaptcha2.0编写GMail验证码样式的图片引擎.
 */
public class GMailEngine extends ListImageCaptchaEngine {
@Override
protected void buildInitialFactories() {
int minWordLength = 4;
int maxWordLength = 4;
int fontSize = 26;
int imageWidth = 110;
int imageHeight = 50;
//在页面上将显示的内容
WordGenerator dictionnaryWords = new RandomWordGenerator("1234567890");
TextPaster randomPaster = new DecoratedRandomTextPaster(minWordLength,
maxWordLength, new RandomListColorGenerator(
new Color[] { new Color(0, 0, 0) }),
new TextDecorator[] {});
BackgroundGenerator background = new UniColorBackgroundGenerator(
imageWidth, imageHeight, Color.white);
FontGenerator font = new RandomFontGenerator(fontSize, fontSize,
new Font[] { new Font("nyala", Font.BOLD, fontSize),
new Font("Bell MT", Font.PLAIN, fontSize),
new Font("Credit valley", Font.BOLD, fontSize) });

ImageDeformation postDef = new ImageDeformationByFilters(new ImageFilter[] {});
ImageDeformation backDef = new ImageDeformationByFilters(new ImageFilter[] {});
ImageDeformation textDef = new ImageDeformationByFilters(new ImageFilter[] {});

WordToImage word2image = new DeformedComposedWordToImage(font,
background, randomPaster, backDef, textDef, postDef);
addFactory(new GimpyFactory(dictionnaryWords, word2image));
}

}

前台JSP

<input class="input" type="text" name="checkCode" id="checkCode" value=""/>
<img id="captcha" src="captcha.svl" onclick="this.src='captcha.svl?d='+new Date()*1"/>

后台Action验证

HttpServletRequest request = ServletActionContext.getRequest();
String sessID = request.getSession().getId();
Boolean isResponseCorrect = JCaptchaServiceSingleton.getInstance().validateResponseForID(sessID, checkCode);
if(isResponseCorrect){
return "true"
}else{
return "false"
}