jcaptcha 自定义验证码例子

jar包：

commons-collections.jar

commons-logging.jar

jcaptcha-1.0-all.jar

public class MyImageSingleton {

private static ImageCaptchaService instance =new DefaultManageableImageCaptchaService();

static {
     instance = new DefaultManageableImageCaptchaService(
        new FastHashMapCaptchaStore(),
        new MyImageCaptchaEngine(),
        180,
        100000,
        75000);
     } 

public static ImageCaptchaService getMyInstance(){
   return instance;
}
}

========================

public class MyImageCaptchaEngine extends ListImageCaptchaEngine {

// 随机生成的字符组成
    private static final String RANDOM_WORD_GENERATOR = "0123456789";

    // 验证码图片上显示的字符个数
    private static final int TEXT_SIZE = 4;
    
    //验证码图片上显示的字符的大小设置
    private static final int TEXT_WIDTH = 12;
    private static final int TEXT_HEIGHT = 13;

    // 验证码图片的大小设置
    private static final int IMAGE_CAPTCHA_WIDTH = 50;
    private static final int IMAGE_CAPTCHA_HEIGHT = 20;

//    protected void buildInitialFactories() {
//        // 随机生成的字符
//        WordGenerator wgen = new RandomWordGenerator(RANDOM_WORD_GENERATOR);
//        RandomRangeColorGenerator cgen = new RandomRangeColorGenerator(
//                new int[]{ 0, 100 }, new int[]{ 0, 100 }, new int[]{ 0, 100 });
//        // 文字显示的个数
//        TextPaster textPaster = new RandomTextPaster(new Integer(TEXT_SIZE),
//                new Integer(TEXT_SIZE), cgen, Boolean.TRUE);
//        // 图片的大小
//        BackgroundGenerator backgroundGenerator = new FunkyBackgroundGenerator(
//                new Integer(IMAGE_CAPTCHA_WIDTH), new Integer(
//                        IMAGE_CAPTCHA_HEIGHT));
//        // 字体格式
//        Font[] fontsList = new Font[]{ new Font("Arial", 0, 12),
//                new Font("Tahoma", 0, 12), new Font("Verdana", 0, 12), };
//        // 文字的大小
//        FontGenerator fontGenerator = new RandomFontGenerator(new Integer(
//                TEXT_WIDTH), new Integer(TEXT_HEIGHT), fontsList);
//
//        WordToImage wordToImage = new ComposedWordToImage(fontGenerator,
//                backgroundGenerator, textPaster);
//        this.addFactory(new GimpyFactory(wgen, wordToImage));
//    }
    
    protected void buildInitialFactories() {
        WordGenerator wgen = new RandomWordGenerator("abcdefghijklmnopquvwxyz123456789");
        RandomRangeColorGenerator cgen = new RandomRangeColorGenerator(
             new int[] {0, 100},
             new int[] {0, 100},
             new int[] {0, 100});
        //文字显示4个数
        TextPaster textPaster = new RandomTextPaster(new Integer(4), new Integer(4), cgen, true);
        //图片的大小
        BackgroundGenerator backgroundGenerator = new FunkyBackgroundGenerator(new Integer(200), new Integer(45));

        Font[] fontsList = new Font[] {
            new Font("Arial", 0, 10),
            new Font("Tahoma", 0, 10),
            new Font("Verdana", 0, 10),
         };
     
        FontGenerator fontGenerator = new RandomFontGenerator(new Integer(20), new Integer(30), fontsList);

         WordToImage wordToImage = new ComposedWordToImage(fontGenerator, backgroundGenerator, textPaster);
         this.addFactory(new GimpyFactory(wgen, wordToImage));
}

==================================

public class MyImageServlet extends HttpServlet {


public void doGet(HttpServletRequest request, HttpServletResponse response)
    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 = request.getSession().getId();
            // call the ImageCaptchaService getChallenge method
            BufferedImage challenge =
                    MyImageSingleton.getMyInstance().getImageChallengeForID(captchaId,
                       request.getLocale());
            // a jpeg encoder
            JPEGImageEncoder jpegEncoder =
                    JPEGCodec.createJPEGEncoder(jpegOutputStream);
            jpegEncoder.encode(challenge);
        } catch (IllegalArgumentException e) {
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        } catch (CaptchaServiceException e) {
        response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return;
        }
        captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
        // flush it in the response
        response.setHeader("Cache-Control", "no-store");
        response.setHeader("Pragma", "no-cache");
        response.setDateHeader("Expires", 0);
        //输出JPEG
        response.setContentType("image/jpeg");
        ServletOutputStream responseOutputStream =
        response.getOutputStream();
        responseOutputStream.write(captchaChallengeAsJpeg);
        responseOutputStream.flush();
        responseOutputStream.close();
}

===========================

web xml
<servlet>
    <servlet-name>MyImageServlet</servlet-name>
    <servlet-class>com.lch.test.checkimg.MyImageServlet</servlet-class>
</servlet>
<servlet>
    <servlet-name>MyCheckImg</servlet-name>
    <servlet-class>com.lch.test.checkimg.MyCheckImg</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>MyImageServlet</servlet-name>
    <url-pattern>/MyImageServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
    <servlet-name>MyCheckImg</servlet-name>
    <url-pattern>/MyCheckImg</url-pattern>
</servlet-mapping>

========================jsp页面

<center>
       <form action="MyCheckImg" method="post"> 
        <img src="MyImageServlet" mce_src="MyImageServlet" /> <input type="text" name="myword" value="" /> 
         <input type="submit"/> 
   </form> 
   <center>

======================提交页面验证Servlet

public class MyCheckImg extends HttpServlet {

public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
   try{
   String sessionID=request.getSession().getId();
   System.out.println(sessionID);
   String myword=request.getParameter("myword");
   System.out.println(myword);

   PrintWriter pw= response.getWriter();
   StringBuffer sb=new StringBuffer();
   ///check
   boolean flg=CaptchaServiceSingleton.getInstance().validateResponseForID(sessionID, myword);
   if(flg){
    sb.append("<font color='red'>check success!</font>");
    System.out.println("验证成功！");
   }else{
    sb.append("<font color='red'>check lose!</font>");
    System.out.println("验证失败！");
   }
   pw.print(sb.toString());
   pw.close();
   }catch(Exception e){
    System.out.println();
   }
}