Java实现的爬虫抓取图片并保存操作示例

import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/*
 * 网络爬虫取数据
 *
 * */
public class JianDan {
  public static String GetUrl(String inUrl){
    StringBuilder sb = new StringBuilder();
    try {
      URL url =new URL(inUrl);
      BufferedReader reader =new BufferedReader(new InputStreamReader(url.openStream()));
      String temp="";
      while((temp=reader.readLine())!=null){
        //System.out.println(temp);
        sb.append(temp);
      }
    } catch (MalformedURLException e) {
      // TODO 自动生成的 catch 块
      e.printStackTrace();
    } catch (IOException e) {
      // TODO 自动生成的 catch 块
      e.printStackTrace();
    }
    return sb.toString();
  }
  public static List<String> GetMatcher(String str,String url){
    List<String> result = new ArrayList<String>();
    Pattern p =Pattern.compile(url);//获取网页地址
    Matcher m =p.matcher(str);
    while(m.find()){
      //System.out.println(m.group(1));
      result.add(m.group(1));
    }
    return result;
  }
  public static void main(String args[]){
    String str=GetUrl("http://www.163.com");
    List<String> ouput =GetMatcher(str,"src=\"([\\w\\s./:]+?)\"");
    for(String temp:ouput){
      //System.out.println(ouput.get(0));
      System.out.println(temp);
    }
    String aurl=ouput.get(0);
     // 构造URL
    URL url;
    try {
      url = new URL(aurl);
       // 打开URL连接
      URLConnection con = (URLConnection)url.openConnection();
       // 得到URL的输入流
      InputStream input = con.getInputStream();
      // 设置数据缓冲
      byte[] bs = new byte[1024 * 2];
      // 读取到的数据长度
      int len;
      // 输出的文件流保存图片至本地
      OutputStream os = new FileOutputStream("a.png");
      while ((len = input.read(bs)) != -1) {
      os.write(bs, 0, len);
      }
      os.close();
      input.close();
    } catch (MalformedURLException e) {
      // TODO 自动生成的 catch 块
      e.printStackTrace();
    } catch (IOException e) {
      // TODO 自动生成的 catch 块
      e.printStackTrace();
    }
  }
}