Java中检测图像编码
我接受图像作为用户的输入。我只想允许 JPEG 图像。图像作为输入流（下面称为 myInputStream）到达。在下面的代码中，ImageIO.getImageReaders() 返回的 Iterator 始终为空。
ImageInputStream imageInputStream = ImageIO.createImageInputStream(
myInputStream);
Iterator<ImageReader> iter = ImageIO.getImageReaders(imageInputStream);
if (!iter.hasNext()) {
// this always happens
}
ImageReader reader = (ImageReader) iter.next();
if (!reader.getFormatName().equals("jpeg")) {
// haven't got this far yet
}
我还尝试将 myInputStream 直接传递给 ImageIO.getImageReaders() ，结果相同。
I'm accepting an image as input from the user. I want to only allow a JPEG image. The image is arriving as an InputStream (called myInputStream below). In the code below, the Iterator returned by ImageIO.getImageReaders() is always empty.
ImageInputStream imageInputStream = ImageIO.createImageInputStream(
myInputStream);
Iterator<ImageReader> iter = ImageIO.getImageReaders(imageInputStream);
if (!iter.hasNext()) {
// this always happens
}
ImageReader reader = (ImageReader) iter.next();
if (!reader.getFormatName().equals("jpeg")) {
// haven't got this far yet
}
I have also tried passing myInputStream directly to ImageIO.getImageReaders() with the same result.
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空迭代器通常意味着 ImageIO 没有找到一个好的图像读取器来解码您的图像。这可能是因为您在类路径中缺少正确的解码器，或者您的图像具有不受支持的颜色模型。
An empty iterator usually means ImageIO hasn't found a good image reader for decoding your image. This may be because you'are missing the right decoder in your classpath, or you image has an unsupported color model.