java 代码判断图片格式后缀名称

/**
* 图片判断
*/
private static String getFormatName(Object o) {
try {
// Create an image input stream on the image
ImageInputStream iis = ImageIO.createImageInputStream(o); // Find all image readers that recognize the image format
Iterator<ImageReader> iter = ImageIO.getImageReaders(iis);
if (!iter.hasNext()) {
// No readers found
return null;
} // Use the first reader
ImageReader reader = (ImageReader) iter.next(); // Close stream
iis.close(); // Return the format name
return reader.getFormatName();
} catch (IOException e) {
//
} // The image could not be read
return null;
}