java创建一个BufferedImage并从中获取一个子图像

Question

I want to be able to get a BufferedImage from a URL / a File and then return a subimage from it. The first issue is that when i try it with

BufferedImage b = null;   
b = ImageIO.read("url");

b just stays null.

Can anyone explain to me how to successfully initialize a BufferedImage, so that I can then get a subimage of it using

BufferedImage c = b.getSubimage(0, 0, 20, 20);

Answer 1

I found it now by myself :^) I just did this :

img = ImageIO.read(new File(filePath));
BufferedImage img2 = img.getSubimage(0,0,100,100);