判断文件是否为gif/jepg/png等格式

public boolean isImage(String contentType, String name) {
int indexOf;
if (isEmpty(contentType) || isEmpty(name) || !contentType.startsWith("image/") || (indexOf = name.lastIndexOf('.')) == -1)
return false;

String suffix = name.substring(indexOf);
return ((contentType.equals("image/jpeg") && (suffix.equals(".jpg") || suffix.equals(".jpeg"))) ||
(contentType.equals("image/png") && suffix.equals(".png")) || (contentType.equals("image/gif") && suffix.equals(".gif")));
}