怎样从网上抓取图片

package com.winkee.wse.util;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;

import javax.imageio.ImageIO;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

public class ImageUtil {

???
??? public static void main(String[] args) throws IOException {
??? ??? // TODO Auto-generated method stub
??? ??? try{
??? ???????? new ImageUtil().createImage(new URL("http://www.google.cn/intl/zh-CN/images/logo_cn.gif"),new File("./loge.jpg"));
??? ???? }catch(Exception e){
??? ???????????? e.printStackTrace();
??? ???? }?
??? }
???
??? public void createImage(File file,File targetFile) throws IOException{
??? ??? Image src=ImageIO.read(file);
??? ??? int width=src.getWidth(null);
??? ??? int height=src.getHeight(null);
??? ??? this.writerToImage(src, targetFile, width, height);
??? }
???
??? public void createImage(File file,File targetFile,int width,int height) throws IOException{
??? ??? Image src=ImageIO.read(file);
??? ??? this.writerToImage(src, targetFile, width, height);
??? }
???
??? public void createImage(URL url,File targetFile) throws IOException{
??? ??? Image src=ImageIO.read(url);
??? ??? int width=src.getWidth(null);
??? ??? int height=src.getHeight(null);
??? ??? this.writerToImage(src, targetFile, width, height);
??? }
???
??? public void createImage(URL url,File targetFile,int width,int height) throws IOException{
??? ??? Image src=ImageIO.read(url);
??? ??? this.writerToImage(src, targetFile, width, height);
??? }
???
??? //生成图片（长width,宽height）并将图片放入targetFile中。
???
??? public void writerToImage(Image src,File targetFile,int width,int height) throws IOException{
??? ??? BufferedImage tag=new BufferedImage(width,height,BufferedImage.TYPE_3BYTE_BGR);
??? ??? tag.getGraphics().drawImage(src,0,0,width,height,null); //绘制缩小后的图
??? ??? FileOutputStream destOut=new FileOutputStream(targetFile); //输出到文件流
??? ??? JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(destOut);
??? ??? encoder.encode(tag); //JPEG编码
??? ??? destOut.close();
??? }
???
}