java批量下图

package fatch;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

/**
 *
 * @author 42
 */
public class Fatch {

    /**
     * 本程序获取http://www.style.com/fashionshows/complete/slideshow/F2014MEN-AMCQUEEN/相册中的30张图片
     * 通过查看图片属性发现其文件名有简单规律，虽不连续但是是有顺序的
     * first,last是网址的前半部分和后半部分
     * 先判断文件是否存在，然后将文件下载到本地
     */
    public static void main(String[] args) throws MalformedURLException, IOException {
        String imagesource="";
        String first="http://www.style.com/fashion-shows/fall-2014-menswear/london/alexander-mcqueen/collection/_ARC0";
        String last=".1366x2048.JPG";
        
        InputStream inputStream;  
        byte[] getData = null;
        for(int i=1,x=0;x<30&&i<=500;i++){
            if(i<10){
                imagesource=first+"00"+i+last;
            }else if((i>=10)&&(i<100)){
                imagesource=first+"0"+i+last;
            }else if((i>=100)&&(i<1000)){
                imagesource=first+i+last;
            }
        URL url = new URL(imagesource);  
        HttpURLConnection conn = (HttpURLConnection)url.openConnection();  
        try {
            inputStream = conn.getInputStream();      //通过输入流获得图片数据
            getData = readInputStream(inputStream);     //获得图片的二进制数据  
        } catch (IOException ex) {
            getData=null;
        }
        
        if(getData!=null){
        File imageFile = new File(i+".JPG");    
        FileOutputStream fos = new FileOutputStream(imageFile);
        fos.write(getData);             
        fos.close();  
          
        System.out.println(x+"picture(s) downloaded"); 
        x++;
        }
        }
        
    }  
  
    public static  byte[] readInputStream(InputStream inputStream) throws IOException {  
        byte[] buffer = new byte[1024];  
        int len = 0;  
        ByteArrayOutputStream bos = new ByteArrayOutputStream();  
        while((len = inputStream.read(buffer)) != -1) {  
            bos.write(buffer, 0, len);  
        }  
          
        bos.close();  
        return bos.toByteArray();
    }
}