程序功能用法：输入网页地址连接（存放在数组中），如 http://news.163.com  (支持同时将几个连接输入);

原理、类包：使用开源类包：HttpClient, NekoHTML, xerces2 ,ExecutorService （java5线程池支持）

所需类包(.jar)：
下载: http://quanta.11tea.com/share/13956

执行代码：

package leung.utils;

import java.io.File;     
import java.io.FileOutputStream;     
import java.util.ArrayList;
import java.util.Date;
import java.util.concurrent.*;
import org.apache.commons.httpclient.HttpClient;     
import org.apache.commons.httpclient.MultiThreadedHttpConnectionManager;
import org.apache.commons.httpclient.methods.GetMethod;     
import org.cyberneko.html.parsers.DOMParser;
import org.w3c.dom.NodeList;

public class GetPhotoByTags {
   
    private HttpClient client = null;
   
 //线程池
 private ExecutorService exe=null;
 //线程池的容量
 private static final int POOL_SIZE=30;
   
    public void test() throws Exception
    {
     
     client = new HttpClient(new MultiThreadedHttpConnectionManager());
     exe = Executors.newFixedThreadPool(POOL_SIZE);
        client.getHttpConnectionManager().getParams().setConnectionTimeout(30000);
        String url;
        DOMParser parser = new DOMParser();
        // links web pages like "http://news.163.com/"
        String[] argv = {
          "http://news.163.com/"
        };
        NodeList nlist = null;
        String postfix = null;
        File folder = null;
        for (int i = 0; i < argv.length; i++) {
         ArrayList<String> al = new ArrayList<String>();
            parser.parse(argv[i]);
            nlist = parser.getDocument().getElementsByTagName("img");
            for(int j=0;j<nlist.getLength();j++)
            {
             al.add(nlist.item(j).getAttributes().getNamedItem("src").getNodeValue().toString());
            }
            Object[] aURLs =al.toArray();
            folder = new File("F:/java_test/photos/"+(new Date()).getTime());
            folder.mkdir();
            for(int j=0;j<aURLs.length;j++)
            {
             url = (String)aURLs[j];
             postfix = url.substring(url.lastIndexOf(".")+1,url.length()).toLowerCase();
             if( postfix.equals("jpg") ||  postfix.equals("jpeg") )
             {
              System.out.println(url);
              // System.out.println(folder);
              loadPage(url,j , folder.getPath()+"/");
             }
           }
        }
       
        exe.shutdown();
        System.out.println("done");
        openFileSystemDir("f:/java_test/photos");
    }

 private void loadPage(final String url,final int i,final String folder)
 {
            // create a new thread to load the URL
  
  
  exe.execute(
            new Thread() {
                public void run() {
                    GetMethod get = new GetMethod(url);
                    get.setFollowRedirects(true);
                   

                    try {
                        client.executeMethod(get);
                        File storeFile = new File(folder+ "pp"+i+".jpg");  
                        FileOutputStream output = new FileOutputStream(storeFile); 
                        output.write(get.getResponseBody());
                        output.close();

                    } catch (Exception ex) {
                        ex.printStackTrace();
                    } finally {
                        get.releaseConnection();
                    }
                }
            }
        );
 }
  
  
 private void openFileSystemDir(String dir)
 {
    String openDirCmdString = "cmd.exe /c start ";
    String openDirCmd = openDirCmdString + dir;
    try{
     Runtime r = Runtime.getRuntime();  
     Process p = r.exec(openDirCmd);
    }catch(Exception e){
     e.printStackTrace();
    }
 }
  
  
  
   public static void main(String[] args){    
      
    try{
     new GetPhotoByTags().test();
    }catch(Exception e){
     
     e.printStackTrace();
     
    }
   }

}

注意：程序对网页中的图片进行了筛选，只保存jpg。程序运行完毕会生成文件夹保存图片。文件夹以时间命名。