利用patchca生成验证码

patchca 是一个简单但功能强大的验证码的Java类库。

在springMVC 中的使用

    /**
     * 验证码
     *
     * @param width  图片宽度
     * @param height 图片高度
     * @param number 验证码数量
     */
    @RequestMapping(value = {"/captcha?w={width}&h={height}&n={number}"})
    public void captcha(HttpServletRequest request,
                        HttpServletResponse response, @PathVariable int width, @PathVariable int height, @PathVariable int number) throws IOException {
        ConfigurableCaptchaService cs = new ConfigurableCaptchaService();
        cs.setColorFactory(new SingleColorFactory(new Color(25, 60, 170)));
        cs.setFilterFactory(new CurvesRippleFilterFactory(cs.getColorFactory()));
        RandomFontFactory ff = new RandomFontFactory();
        ff.setMinSize(30);
        ff.setMaxSize(30);
        RandomWordFactory rwf = new RandomWordFactory();
        rwf.setMinLength(number);
        rwf.setMaxLength(number);
        cs.setWordFactory(rwf);
        cs.setFontFactory(ff);
        cs.setHeight(height);
        cs.setWidth(width);

        response.setContentType("image/png");
        response.setHeader("Cache-Control", "no-cache, no-store");
        response.setHeader("Pragma", "no-cache");
        long time = System.currentTimeMillis();
        response.setDateHeader("Last-Modified", time);
        response.setDateHeader("Date", time);
        response.setDateHeader("Expires", time);
        
        ServletOutputStream stream = response.getOutputStream();
        String validate_code = EncoderHelper.getChallangeAndWriteImage(cs,
                "png", stream);

        request.getSession().setAttribute("REG_VAL_CODE", validate_code);

        stream.flush();
        stream.close();
    }

jar下载地址：http://code.google.com/p/patchca/downloads/list 
源码下载地址：https://github.com/pusuo/patchca