java image 缩小尺寸

import java.awt.Image;import java.awt.image.BufferedImage;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import javax.imageio.ImageIO;public class T {/** * @param args * @throws IOException  */public static void main(String[] args) throws IOException {  File srcfile = new File("d:\\Desert.jpg");                          //载入图片文件           Image src = javax.imageio.ImageIO.read(srcfile);           int width = src.getWidth(null);    //得到源图宽           int h0 = src.getHeight(null);   //得到源图长                   if(width > 720)        {         BufferedImage tag= new BufferedImage(720, 720*h0/width, BufferedImage.TYPE_INT_RGB);                          //保存文件            //绘制缩小后的图            tag.getGraphics().drawImage(src.getScaledInstance(720, 720*h0/width,  Image.SCALE_SMOOTH), 0, 0,  null);                         ImageIO.write(tag, "JPEG", new FileOutputStream(srcfile));        } }  }