JPEGImageEncoder在JDK 7中不起作用 [英] JPEGImageEncoder don't work in JDK 7

问题描述

我尝试使用JCaptcha组件制作验证码，并且我需要在相关的servlet中对图像进行编码.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?
这是代码的相关部分:

I try to make captcha using JCaptcha Component and i need to encode image in related servlet. So according to JCaptcha Tutorial, I should use JPEGImageEncoder and it's not compatible with JDK7. What else can i do?
here is related part of code:

     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;
     }

推荐答案

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功能.

This replaces the internal and deprecated JPEG functions.

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