java 解析图片类型 代码片段

package test;


import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;


import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;


public class Test {
        public static void main(String[] args) throws IOException{
                File file = new File("D:\\logo.png");
                InputStream is = new FileInputStream(file);
                
            ImageInputStream iis = ImageIO.createImageInputStream(is);
            Iterator<ImageReader> iter =ImageIO.getImageReaders(iis);
            if(!iter.hasNext()) {
                    return;
            }
            ImageReader reader = iter.next();
            iis.close();
            String name = reader.getFormatName();
            System.out.println(name);
        }
}