可以根据图片中取出的byte[]判断图片格式
byte b[]=new byte[256]; stream.read(b,0,255); System.out.println("******bytes******"); for(int i=0;i<b.length;i++){ System.out.print(Integer.toHexString(b[i]&0x0ff)+" "); } System.out.println(); System.out.println("******ascii******"); System.out.println(new String(b));
bmp:
42 4d
BM (2bytes)
jpeg:
ff d8
gif:
47 49 46
GIF (3bytes)
png:
89 50 4E 47