Question

我尝试使用JCaptcha组件创建验证码，我需要在相关的servlet中编码图像。所以根据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：

     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：

// Image writer
    ImageWriter 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);

这将取代已弃用的JPEG函数

JPEGImageEncoder不适用于JDK 7

1 个答案: