JPEGImageEncoder不适用于JDK 7

Question

我尝试使用JCaptcha组件来制作captcha，并且需要在相关servlet中编码图像。因此，根据JCaptcha教程，我应该使用JPEGImageEncoder，它与JDK7不兼容。我还能做什么？

下面是代码的相关部分：

     ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
     BufferedImage challenge =
             CaptchaServiceSingleton.getInstance().getImageChallengeForID(captchaId,
                     httpServletRequest.getLocale());
   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;
     }

Answer 1

使用ImageIO

ImageWriter imageWriter = 
    ImageIO.getImageWritersBySuffix("jpeg").next();
ImageOutputStream ios = 
    ImageIO.createImageOutputStream(jpegOutputStream);
imageWriter.setOutput(ios);
IIOMetadata imageMetaData = imageWriter.getDefaultImageMetadata(
    new ImageTypeSpecifier(challenge), null);
imageWriter.write(
    imageMetaData, new IIOImage(challenge, null, null), null);

这将替换内部和不推荐使用的JPEG函数。