超棒的验证码生成组件---Jcaptcha

最近由于Springside3的发布，也来凑热闹学习学习， 毕竟是国人的开源项目。 由于之前仅仅有听过，但是没有具体研究，所以算比较落后的。 不过这个项目确实是非常好的项目， 从中可以了解不少新新东西（ -


可能是我太过时了！）

正好我最近需要给老婆开发个小东西，其中有用到验证码的生成， 在Springside里面找到个非常棒的组件---Jcaptcha

Springside对其做了封装，而且其官方的文档看起来也比较费力。所以自己琢磨了半天，才学会一个小的demo。

这里发上来， 希望能帮助有需要的人， （本人在网上找了不少资料， 所给的素材不是不全就是说的不太明白）

OK，开始，我先从一个示例开始。

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代码

<?
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:

Java代码

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

Java代码

<%@ 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
)

Java代码

<%@ 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：

Java代码

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：

Java代码

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:

Java代码

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：



OK, 先写到这，希望对有需要的人有帮助。

如果有人懒得敲代码，我这里附上我的工程源代码， 不过我还是觉得，咱弄技术的人， 就得把键盘当筷子， 你见过非常饿，但不想拿筷子的人吗？（别说老外用叉子……）