java HTTP 获取网页图片

摘选与别人博客：

 

package com.test;

import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Random;

import javax.imageio.ImageIO;

 

public class HttpGetImage {

 /**
  * @param args
  * @throws Exception
  */
 public static String getImgFromUrl(String urlstr, String savepath)
    {
        int num = urlstr.indexOf('/',8);
        int extnum = urlstr.lastIndexOf('.');
        String u = urlstr.substring(0,num);
        String ext = urlstr.substring(extnum+1,urlstr.length());
        try{
            long curTime = System.currentTimeMillis();
            Random random = new Random(100000000);
            String fileName = String.valueOf(curTime) + "_"
                    + random.nextInt(100000000) + "."+ext;
            // 图片的路径
            String realPath ="d:/";
           
            URL url = new URL(urlstr);
            URLConnection connection = url.openConnection();
            connection.setDoOutput(true);//URL连接可以用于输入输出。将doOutput标签设置为true表示应用将向URL连接中写入数据,默认为false
            connection.setRequestProperty("referer", u);       //通过这个http头的伪装来反盗链
            BufferedImage image = ImageIO.read(connection.getInputStream());
            FileOutputStream fout=new FileOutputStream(realPath+fileName);
            if("gif".equals(ext)||"png".equals(ext))
            {
                 ImageIO.write(image, ext, fout);
            }
            ImageIO.write(image, "jpg", fout);

            //gif格式图片要write两次，否则生成不了图片，不理解，望后来人指教。
            fout.flush();
            fout.close();
             return savepath+fileName;
        }      
        catch(Exception e)
        {
            System.out.print(e.getMessage().toString());
        }
        return "";
    }
 
 

 public static void main(String[] args) throws Exception {
  // TODO Auto-generated method stub
  System.out.println(getImgFromUrl("http://c.csdn.net/bbs/t/5/i/pic_logo.gif","d:/"));
 }

}