利用Java如何实现爬取网络图片并保存

package getUrlPic;

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

public class GetUrlPic {
 
 public static void main(String[] args) throws Exception { 
  //new一个URL对象 
  URL url = new URL("http://www.gz135.cn/data/attachment/forum/201702/13/165605xyayykq5vy4h81vy.jpg"); 
  //打开链接 
  HttpURLConnection conn = (HttpURLConnection)url.openConnection(); 
  //设置请求方式为"GET" 
  conn.setRequestMethod("GET"); 
  //超时响应时间为5秒 
  conn.setConnectTimeout(5 * 1000); 
  //通过输入流获取图片数据 
  InputStream inStream = conn.getInputStream(); 
  //得到图片的二进制数据，以二进制封装得到数据，具有通用性 
  byte[] data = readInputStream(inStream); 
  //new一个文件对象用来保存图片，默认保存当前工程根目录 
  File imageFile = new File("pic20170419.jpg"); 
  //创建输出流 
  FileOutputStream outStream = new FileOutputStream(imageFile); 
  //写入数据 
  outStream.write(data); 
  //关闭输出流 
  outStream.close(); 
 } 
 public static byte[] readInputStream(InputStream inStream) throws Exception{ 
  ByteArrayOutputStream outStream = new ByteArrayOutputStream(); 
  //创建一个Buffer字符串 
  byte[] buffer = new byte[1024]; 
  //每次读取的字符串长度，如果为-1，代表全部读取完毕 
  int len = 0; 
  //使用一个输入流从buffer里把数据读取出来 
  while( (len=inStream.read(buffer)) != -1 ){ 
   //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度 
   outStream.write(buffer, 0, len); 
  } 
  //关闭输入流 
  inStream.close(); 
  //把outStream里的数据写入内存 
  return outStream.toByteArray(); 
 } 

}