验证码生成组件---Jcaptcha

首先来看看示例的目录结构：

    
       

 

       在Jcaptcha的官方文档中有一个 5分钟快速入门的文章， 是介绍快速开发的文章。 有兴趣的可以去上面看看。

      这里我发上我的源代码:

 

 

     web.xml中:

 

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
     "http://java.sun.com/dtd/web-app_2_3.dtd">
 <web-app>

     <servlet>
         <servlet-name>jcaptcha</servlet-name>
         <servlet-class>com.ivan.zhang.servlet.ImageCaptchaServlet</servlet-class>
         <load-on-startup>0</load-on-startup>
     </servlet>
     <servlet-mapping>
         <servlet-name>jcaptcha</servlet-name>
         <url-pattern>/jcaptcha</url-pattern>
     </servlet-mapping>
 </web-app>

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>

	<servlet>
		<servlet-name>jcaptcha</servlet-name>
		<servlet-class>com.ivan.zhang.servlet.ImageCaptchaServlet</servlet-class>
		<load-on-startup>0</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>jcaptcha</servlet-name>
		<url-pattern>/jcaptcha</url-pattern>
	</servlet-mapping> 
</web-app>

 

    再需要一个服务类，用来产生Image Service类:

 

package com.ivan.zhang.servlet;

 import java.awt.image.BufferedImage;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;

 import javax.imageio.ImageIO;
 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 com.ivan.zhang.CaptchaServiceSingleton;
 import com.octo.captcha.service.CaptchaServiceException;
 import com.sun.image.codec.jpeg.JPEGCodec;
 import com.sun.image.codec.jpeg.JPEGImageEncoder;

 public class ImageCaptchaServlet extends HttpServlet {

     /**
     *
     */
     private static final long serialVersionUID = 1L;

     public void init(ServletConfig servletConfig) throws ServletException {
         super.init(servletConfig);
    }

     protected void doGet(HttpServletRequest httpServletRequest,
             HttpServletResponse httpServletResponse) throws ServletException,
            IOException {

         byte[] captchaChallengeAsJpeg = null;
         // the output stream to render the captcha image as jpeg into
         ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
         try {
             // get the session id that will identify the generated captcha.
             // the same id must be used to validate the response, the session id
             // is a good candidate!
            String captchaId = httpServletRequest.getSession().getId();
             // call the ImageCaptchaService getChallenge method
            BufferedImage challenge = CaptchaServiceSingleton.getInstance()
                    .getImageChallengeForID(captchaId,
                            httpServletRequest.getLocale());

             // a jpeg encoder
            JPEGImageEncoder jpegEncoder = JPEGCodec
                    .createJPEGEncoder(jpegOutputStream);
            jpegEncoder.encode(challenge);
         } catch (IllegalArgumentException e) {
            httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
             return;
         } catch (CaptchaServiceException e) {
            httpServletResponse
                    .sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
             return;
        }
        captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
         // flush it in the response
         httpServletResponse.setHeader("Cache-Control", "no-store");
         httpServletResponse.setHeader("Pragma", "no-cache");
         httpServletResponse.setDateHeader("Expires", 0);
         httpServletResponse.setContentType("image/jpeg");
        ServletOutputStream responseOutputStream = httpServletResponse
                .getOutputStream();
        responseOutputStream.write(captchaChallengeAsJpeg);

        responseOutputStream.flush();
        responseOutputStream.close();
    }
}

package com.ivan.zhang.servlet;

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

import javax.imageio.ImageIO;
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 com.ivan.zhang.CaptchaServiceSingleton;
import com.octo.captcha.service.CaptchaServiceException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImageCaptchaServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public void init(ServletConfig servletConfig) throws ServletException {
		super.init(servletConfig);
	}

	protected void doGet(HttpServletRequest httpServletRequest,
			HttpServletResponse httpServletResponse) throws ServletException,
			IOException {

		byte[] captchaChallengeAsJpeg = null;
		// the output stream to render the captcha image as jpeg into
		ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
		try {
			// get the session id that will identify the generated captcha.
			// the same id must be used to validate the response, the session id
			// is a good candidate!
			String captchaId = httpServletRequest.getSession().getId();
			// call the ImageCaptchaService getChallenge method
			BufferedImage challenge = CaptchaServiceSingleton.getInstance()
					.getImageChallengeForID(captchaId,
							httpServletRequest.getLocale());

			// a jpeg encoder
			JPEGImageEncoder jpegEncoder = JPEGCodec
					.createJPEGEncoder(jpegOutputStream);
			jpegEncoder.encode(challenge);
		} catch (IllegalArgumentException e) {
			httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		} catch (CaptchaServiceException e) {
			httpServletResponse
					.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
			return;
		}
		captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
		// flush it in the response
		httpServletResponse.setHeader("Cache-Control", "no-store");
		httpServletResponse.setHeader("Pragma", "no-cache");
		httpServletResponse.setDateHeader("Expires", 0);
		httpServletResponse.setContentType("image/jpeg");
		ServletOutputStream responseOutputStream = httpServletResponse
				.getOutputStream();
		responseOutputStream.write(captchaChallengeAsJpeg);
		
		responseOutputStream.flush();
		responseOutputStream.close();
	}
}

 

   OK,后台的类写完了， 现在我们来看看前台页面的编写:

 

   index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
     pageEncoding="UTF-8"%>
 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
 <form action="sample.jsp">
     <img src="jcaptcha">
     <input type='text' name='j_captcha_response' value=''>
</form>
</body>
</html>

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="sample.jsp">
	<img src="jcaptcha">
	<input type='text' name='j_captcha_response' value=''>
</form>
</body>
</html>

 

    sample.jsp: (用来验证的页面 )

 

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
     pageEncoding="UTF-8"%>
 <%@page import="com.octo.captcha.service.CaptchaServiceException"%>
 <%@page import="com.ivan.zhang.CaptchaServiceSingleton"%>
<%
    Boolean isResponseCorrect = Boolean.FALSE;
     //remenber that we need an id to validate!
    String captchaId = request.getSession().getId();
     //retrieve the response
     String responsestr = request.getParameter("j_captcha_response");
     // Call the Service method
     try {
        isResponseCorrect = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId, responsestr);
         if(isResponseCorrect){

         }else{
             out.print("It's worng......");
        }
     } catch (CaptchaServiceException e) {
         //should not happen, may be thrown if the id is not valid
    }
%>

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="UTF-8"%>
<%@page import="com.octo.captcha.service.CaptchaServiceException"%>
<%@page import="com.ivan.zhang.CaptchaServiceSingleton"%>
<%
	Boolean isResponseCorrect = Boolean.FALSE;
	//remenber that we need an id to validate!
	String captchaId = request.getSession().getId();
	//retrieve the response
	String responsestr = request.getParameter("j_captcha_response");
	// Call the Service method
	try {
		isResponseCorrect = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId, responsestr);
		if(isResponseCorrect){
			
		}else{
			out.print("It's worng......");
		}
	} catch (CaptchaServiceException e) {
		//should not happen, may be thrown if the id is not valid
	}
%>

 

   这样，我们的第一个版本出来了， 我们来看看效果：

   

 

  我们看到， 虽然生成了验证码，但是这样的图片给人非常不友好的感觉，  所以我参考Springside中的一样，自己给他设定产生图片的样式：

   要实现自定义样式，我们需要一下2个步骤： 

   1. 告诉Jcaptcha 我要的样式是什么样子.

   2. 在提交后，利用我们自己的样式来产生图片.

 

  所以，我们改动一下 :

    新加一个类GmailEngine.java(直接拿至Springside ，非常感谢白衣的共享，让我们这样的菜鸟学到很多东西.)

   

 

  其中代码如下：

 

package com.ivan.zhang.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.FileDictionary;
 import com.octo.captcha.component.word.wordgenerator.ComposeDictionaryWordGenerator;
 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.
 *
 * @author calvin
 */
 public class GMailEngine extends ListImageCaptchaEngine {
     @Override
     protected void buildInitialFactories() {
         int minWordLength = 4;
         int maxWordLength = 5;
         int fontSize = 50;
         int imageWidth = 250;
         int imageHeight = 100;

         //word generator
         WordGenerator dictionnaryWords = new ComposeDictionaryWordGenerator(new FileDictionary("toddlist"));

         //word2image components
         TextPaster randomPaster = new DecoratedRandomTextPaster(minWordLength, maxWordLength,
                 new RandomListColorGenerator(new Color[] { new Color(23, 170, 27), new Color(220, 34, 11),
                         new Color(23, 67, 172) }), 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));
    }

}

package com.ivan.zhang.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.FileDictionary;
import com.octo.captcha.component.word.wordgenerator.ComposeDictionaryWordGenerator;
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.
 * 
 * @author calvin
 */
public class GMailEngine extends ListImageCaptchaEngine {
	@Override
	protected void buildInitialFactories() {
		int minWordLength = 4;
		int maxWordLength = 5;
		int fontSize = 50;
		int imageWidth = 250;
		int imageHeight = 100;

		//word generator
		WordGenerator dictionnaryWords = new ComposeDictionaryWordGenerator(new FileDictionary("toddlist"));

		//word2image components
		TextPaster randomPaster = new DecoratedRandomTextPaster(minWordLength, maxWordLength,
				new RandomListColorGenerator(new Color[] { new Color(23, 170, 27), new Color(220, 34, 11),
						new Color(23, 67, 172) }), 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));
	}

}

 

   如果有玩过Swing的兄弟，应该会很好理解上面的代码。

 

   继续，我们有了自己的样式类， 接下来我们就要告诉servlet我们需要用哪个样式生成图片。

   就有如下，将CaptchaServiceSingleton类修改一下：

 

package com.ivan.zhang;

 import com.ivan.zhang.servlet.GMailEngine;
 import com.octo.captcha.engine.GenericCaptchaEngine;
 import com.octo.captcha.service.CaptchaService;
 import com.octo.captcha.service.captchastore.FastHashMapCaptchaStore;
 import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;
 import com.octo.captcha.service.image.ImageCaptchaService;

 /**
 * 按照官方的做法： 一定为单例
 * @author Administrator
 *
 */
 public class CaptchaServiceSingleton {
      private static ImageCaptchaService instance = new DefaultManageableImageCaptchaService(
                new FastHashMapCaptchaStore(), new GMailEngine(), 180,
                100000 , 75000);
     public static ImageCaptchaService getInstance(){
         return instance;
    }
}

package com.ivan.zhang;

import com.ivan.zhang.servlet.GMailEngine;
import com.octo.captcha.engine.GenericCaptchaEngine;
import com.octo.captcha.service.CaptchaService;
import com.octo.captcha.service.captchastore.FastHashMapCaptchaStore;
import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;
import com.octo.captcha.service.image.ImageCaptchaService;

/**
 * 按照官方的做法： 一定为单例
 * @author Administrator
 *
 */
public class CaptchaServiceSingleton {
	 private static ImageCaptchaService instance = new DefaultManageableImageCaptchaService(
			   new FastHashMapCaptchaStore(), new GMailEngine(), 180,
			   100000 , 75000);
    public static ImageCaptchaService getInstance(){
        return instance;
    }
}

 

    同样的，修改一下Servlet类:

 

    改动如下:

 

package com.ivan.zhang.servlet;

 import java.awt.image.BufferedImage;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;

 import javax.imageio.ImageIO;
 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 com.ivan.zhang.CaptchaServiceSingleton;
 import com.octo.captcha.service.CaptchaServiceException;
 import com.sun.image.codec.jpeg.JPEGCodec;
 import com.sun.image.codec.jpeg.JPEGImageEncoder;

 public class ImageCaptchaServlet extends HttpServlet {

     /**
     *
     */
     private static final long serialVersionUID = 1L;

     public void init(ServletConfig servletConfig) throws ServletException {
         super.init(servletConfig);
    }

     protected void doGet(HttpServletRequest httpServletRequest,
             HttpServletResponse httpServletResponse) throws ServletException,
            IOException {
        genernateCaptchaImage(httpServletRequest, httpServletResponse);
    }


     /**
     * 生成验证码图片.
     */
     private void genernateCaptchaImage(final HttpServletRequest request, final HttpServletResponse response)
             throws IOException {
         response.setHeader("Cache-Control", "no-store");
         response.setHeader("Pragma", "no-cache");
         response.setDateHeader("Expires", 0);
         response.setContentType("image/jpeg");
        ServletOutputStream out = response.getOutputStream();
         try {
             String captchaId = request.getSession(true).getId();
            BufferedImage challenge = (BufferedImage)  CaptchaServiceSingleton.getInstance().getChallengeForID(captchaId, request.getLocale());
             ImageIO.write(challenge, "jpg", out);
            out.flush();
         } catch (CaptchaServiceException e) {
         } finally {
            out.close();
        }
    }
}

package com.ivan.zhang.servlet;

import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

import javax.imageio.ImageIO;
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 com.ivan.zhang.CaptchaServiceSingleton;
import com.octo.captcha.service.CaptchaServiceException;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImageCaptchaServlet extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public void init(ServletConfig servletConfig) throws ServletException {
		super.init(servletConfig);
	}

	protected void doGet(HttpServletRequest httpServletRequest,
			HttpServletResponse httpServletResponse) throws ServletException,
			IOException {
		genernateCaptchaImage(httpServletRequest, httpServletResponse);
	}
	
	
	/**
	 * 生成验证码图片.
	 */
	private void genernateCaptchaImage(final HttpServletRequest request, final HttpServletResponse response)
			throws IOException {
		response.setHeader("Cache-Control", "no-store");
		response.setHeader("Pragma", "no-cache");
		response.setDateHeader("Expires", 0);
		response.setContentType("image/jpeg");
		ServletOutputStream out = response.getOutputStream();
		try {
			String captchaId = request.getSession(true).getId();
			BufferedImage challenge = (BufferedImage)  CaptchaServiceSingleton.getInstance().getChallengeForID(captchaId, request.getLocale());
			ImageIO.write(challenge, "jpg", out);
			out.flush();
		} catch (CaptchaServiceException e) {
		} finally {
			out.close();
		}
	}
}

 

  OK, 这样我们产生的图片样式就会好看多了。 不相信？  OK， 非要上图才有人相信。

    截图如下:

    再来一下刷新：

   

 

    http://www.iteye.com/topic/567144