无需从 java 中的 web 下载即可获取图像大小

Question

I want to get height, width, and size in bytes without downloading them completely. I need to do that in java. Is there any way to get images metadata without download those images completely?

Answer 1

All those informations are kept in the image itself. (From my knowledge) You can only do what you're asking if you have an API that you can consume which will tell you those informations beforehand but you can't get that from an URL at the end of which you find the image byte array.

Answer 2

If you could selectively download only the exif data, you'd be fine, but depending on the image format the location of it may be unknown before actually downloading the entire image to parse it. What you can do is make a HTTP HEAD request to only get the Content-Length and Content-Type headers though, and make some qualified guesses about the image size. This gives no information about aspect, width or height of course, only the number of bytes.