java - 如何解决 : javax. imageio.IIOException:虚假输入色彩空间

Question

我有一个函数generateImageOutput，可以将BufferedImage写入jpeg文件。

public boolean generateImageOutput(BufferedImage image, String filename){
        //The image is written to the file by the writer
        File file = new File( projectFolder+"/data/"+filename+".jpg");
        //Iterator containing all ImageWriter (JPEG)
        Iterator encoder = ImageIO.getImageWritersByFormatName("JPEG");
        ImageWriter writer = (ImageWriter) encoder.next();
        //Compression parameter (best quality)
        ImageWriteParam param = writer.getDefaultWriteParam();
        param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
        param.setCompressionQuality(1.0f);
        //Try to write the image
        try{
            ImageOutputStream outputStream = ImageIO.createImageOutputStream(file);
            writer.setOutput(outputStream);
            writer.write(null, new IIOImage(image, null, null), param);
            outputStream.flush();
            writer.dispose();
            outputStream.close();
        }catch(IOException e){
            e.printStackTrace();
            System.out.println(e.toString());
            return false;
        }
        return true;
    }

它适用于某些情况，但对于从 Base64 字符串转换而来的 BufferedImage 则失败:

String encodedString = JSON.parseObject(string).getString("image");
byte[] decodedBytes = Base64.getDecoder().decode(encodedString);
ByteArrayInputStream bis = new ByteArrayInputStream(decodedBytes);
buffered_image = ImageIO.read(bis);

当使用generateImageOutput将上述buffered_image写入jpeg时，它会引发异常:

javax.imageio.IIOException: Bogus input colorspace
    at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageWriter.writeImage(Native Method)
    at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageWriter.writeOnThread(JPEGImageWriter.java:1007)
    at java.desktop/com.sun.imageio.plugins.jpeg.JPEGImageWriter.write(JPEGImageWriter.java:371)

字符串encodedString没有问题，我已经成功在线将其转换为图像。

如何解决异常？

Answer 1

根据@J.doe，Alpha channel 必须被删除。我有一个删除 Alpha channel 的代码。下面的代码用于确定图像是否具有 Alpha channel 。如果图像有 Alpha channel ，它将创建一个没有 Alpha channel 的图像。

private static BufferedImage removeAlphaChannel(BufferedImage img) {
    if (!img.getColorModel().hasAlpha()) {
        return img;
    }

    BufferedImage target = createImage(img.getWidth(), img.getHeight(), false);
    Graphics2D g = target.createGraphics();
    // g.setColor(new Color(color, false));
    g.fillRect(0, 0, img.getWidth(), img.getHeight());
    g.drawImage(img, 0, 0, null);
    g.dispose();

    return target;
}
private static BufferedImage createImage(int width, int height, boolean hasAlpha) {
    return new BufferedImage(width, height, hasAlpha ? BufferedImage.TYPE_INT_ARGB : BufferedImage.TYPE_INT_RGB);
}