验证码例子（jcaptcha插件的使用）
和上一篇验证码的例子（kaptcha插件的使用）类似，同样加进了spring mvc、jquery
项目目录结构：
pom.xml
4.0.0
com.royal
verifyCode_jcaptcha
0.0.1-SNAPSHOT
jar
verifyCode_jcaptcha
http://maven.apache.org
UTF-8
junit
junit
3.8.1
test
com.octo.captcha
jcaptcha-all
1.0-RC6
commons-logging
commons-logging
1.1.1
org.springframework
spring-aop
3.1.0.RELEASE
org.springframework
spring-asm
3.1.0.RELEASE
org.springframework
spring-aspects
3.1.0.RELEASE
org.springframework
spring-beans
3.1.0.RELEASE
org.springframework
spring-context
3.1.0.RELEASE
org.springframework
spring-context-support
3.1.0.RELEASE
org.springframework
spring-core
3.1.0.RELEASE
org.springframework
spring-expression
3.1.0.RELEASE
org.springframework
spring-instrument
3.1.0.RELEASE
org.springframework
spring-jdbc
3.1.0.RELEASE
org.springframework
spring-jms
3.1.0.RELEASE
org.springframework
spring-orm
3.1.0.RELEASE
org.springframework
spring-oxm
3.1.0.RELEASE
org.springframework
spring-test
3.1.0.RELEASE
org.springframework
spring-tx
3.1.0.RELEASE
org.springframework
spring-web
3.1.0.RELEASE
org.springframework
spring-webmvc
3.1.0.RELEASE
org.springframework
spring-webmvc-portlet
3.1.0.RELEASE
org.apache.tomcat
jsp-api
6.0.35
web.xml
jcaptcha
com.royal.servlet.ImageCaptchaServlet
0
mvc-dispatcher
org.springframework.web.servlet.DispatcherServlet
1
contextConfigLocation
/WEB-INF/spring-mvc.xml
default
*.css
default
*.gif
default
*.jpg
default
*.js
jcaptcha
/jcaptcha
mvc-dispatcher
/
index.jsp
spring-mvc.xml
CaptchaServiceSingleton.java
package com.royal.verifyCode_jcaptcha;
import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;
import com.octo.captcha.service.image.ImageCaptchaService;
/**
* 实例一个jcaptcha服务，注意，必须是单例模式
*/
public class CaptchaServiceSingleton {
private static ImageCaptchaService instance = new DefaultManageableImageCaptchaService();
public static ImageCaptchaService getInstance(){
return instance;
}
}
ImageCaptchaServlet.java
package com.royal.servlet;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
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.royal.verifyCode_jcaptcha.CaptchaServiceSingleton;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
/**
* 一个产生图片的servlet
*/
public class ImageCaptchaServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
byte[] captchaChallengeAsJpeg = null;
//the output stream to render the captcha image as jpeg into
ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
//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 = req.getSession().getId();
//call the ImageCaptchaService getChallenge method
BufferedImage challenge = CaptchaServiceSingleton.getInstance().getImageChallengeForID(captchaId, req.getLocale());
//a jpeg encoder
JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(jpegOutputStream);
jpegEncoder.encode(challenge);
captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
// flush it in the response
resp.setHeader("Cache-Control", "no-store");
resp.setHeader("Pragma", "no-cache");
resp.setDateHeader("Expires", 0);
resp.setContentType("image/jpeg");
ServletOutputStream responseOutputStream = resp.getOutputStream();
responseOutputStream.write(captchaChallengeAsJpeg);
responseOutputStream.flush();
responseOutputStream.close();
}
}
也就是当你点击图片进行刷新的时候，访问的就是这个servlet（用于生成验证码图片）
这里可能有个小问题:
当你要用 JPEGImageEncoder 和 JPEGCodec，你会发现无法导入rt.jar里面的 com.sun.image.codec.jpeg.JPEGCodec
com.sun.image.codec.jpeg.JPEGImageEncoder
这两个类
解决办法：deprecated and restricted API--- Forbidden 选项改为warning
参考：http://blog.csdn.net/oney139/article/details/6539624
mvc 控制类
VerifyJcaptchaController.java
package com.royal.controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;
import com.royal.verifyCode_jcaptcha.CaptchaServiceSingleton;
public class VerifyJcaptchaController extends AbstractController{
@Override
protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {
Boolean isResponseCorrect = Boolean.FALSE;
//remenber that we need an id to validate!
String captchaId = request.getSession().getId();
System.out.println("captchaId---" + captchaId);
//retrieve the response
String resp = request.getParameter("j_captcha_response");
System.out.println("j_captcha_response---" + resp);
// Call the Service method
isResponseCorrect = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId, resp);
System.out.println("isResponseCorrect---" + isResponseCorrect);
if(isResponseCorrect == true){
return new ModelAndView("success");
}else{
System.out.println("FAIL..");
return null;
}
}
}
同样别忘了maven build...
启动tomcat，访问：http://localhost:8080/verifyCode_jcaptcha/
demo算是demo完了，但总觉得变扭，图片好像不怎么好看，图片大小不知道怎么改。API没看。
官方：http://jcaptcha.sourceforge.net/
千篇一律的这个不完整例子 参考：http://www.blogjava.net/alex/archive/2006/06/11/51976.html