使用Jsoup 爬取网易首页所有的图片

package com.enation.newtest;
 
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
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;
 
import org.apache.commons.lang3.StringEscapeUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
 
// 爬取网易首页所有图片
public class Jsoup163 {
 
    public static void main(String[] args) throws Exception{
        String downloadPath = "D:\\360Downloads\\test";
        List<String> list = nameList("网易--首页");
        getPictures(list,1,downloadPath); //1代表下载一页，一页一般有30张图片
    }
 
    public static void getPictures(List<String> keywordList, int max,String downloadPath) throws Exception{ // key为关键词,max作为爬取的页数
        String gsm=Integer.toHexString(max)+"";
        String finalURL = "";
        String tempPath = "";
        for(String keyword : keywordList){
            tempPath = downloadPath;
            if(!tempPath.endsWith("\\")){
                       tempPath = downloadPath+"\\";
            }
            tempPath = tempPath+keyword+"\\";
            File f = new File(tempPath);
            if(!f.exists()){
                f.mkdirs();
            }
            int picCount = 1;
            for(int page=1;page<=max;page++) {
                sop("正在下载第"+page+"页面");
                Document document = null;
                try {
                    String url ="http://www.163.com/";
                    sop(url);
                    document = Jsoup.connect(url).data("query", "Java")//请求参数
                             .userAgent("Mozilla/4.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)")//设置urer-agent  get();
                             .timeout(5000)
                             .get();
                    String xmlSource = document.toString();
                    xmlSource = StringEscapeUtils.unescapeHtml3(xmlSource);
                    //sop(xmlSource);
                    String reg = "<img.*src=(.*?)[^>]*?>";
                    String reg2 = "src\\s*=\\s*\"?(.*?)(\"|>|\\s+)";
                    String reg2datasrc = "data-src\\s*=\\s*\"?(.*?)(\"|>|\\s+)";
 
                    Pattern pattern = Pattern.compile(reg);
                    Pattern pattern2 = Pattern.compile(reg2);
                    Pattern pattern2datasrc = Pattern.compile(reg2datasrc);
 
                    Matcher m = pattern.matcher(xmlSource);
                    while (m.find()){
                        finalURL = m.group();
                        System.out.println(finalURL);
                        Matcher m2 = null;
                        if(finalURL.indexOf("data-src")>0){
                            m2 = pattern2datasrc.matcher(finalURL);
                        }else {
                            m2 = pattern2.matcher(finalURL);
                        }
                        if(m2.find()){
                            finalURL = m2.group(1);
                            System.out.println(finalURL);
                            if(finalURL.startsWith("http")){
                                sop(keyword+picCount+++":"+finalURL);
                                download(finalURL,tempPath);
                                sop("             下载成功");
                            }
                        }
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
       }
       sop("下载完毕");
       delMultyFile(downloadPath);
       sop("已经删除所有空图");
    }
    public static void delMultyFile(String path){
        File file = new File(path);
        if(!file.exists())
            throw new RuntimeException("File \""+path+"\" NotFound when excute the method of delMultyFile()....");
        File[] fileList = file.listFiles();
        File tempFile=null;
        for(File f : fileList){
            if(f.isDirectory()){
                delMultyFile(f.getAbsolutePath());
            }else{
                if(f.length()==0)
                    sop(f.delete()+"---"+f.getName());
            }
        }
    }
    public static List<String> nameList(String nameList){
        List<String> arr = new ArrayList<String>();
        String[] list;
        if(nameList.contains(","))
            list= nameList.split(",");
        else if(nameList.contains("、"))
            list= nameList.split("、");
        else if(nameList.contains(" "))
            list= nameList.split(" ");
        else{
            arr.add(nameList);
            return arr;
        }
        for(String s : list){
            arr.add(s);
        }
        return arr;
    }
    public static void sop(Object obj){
        System.out.println(obj);
    }
    //根据图片网络地址下载图片
      public static void download(String url,String path){
          //path = path.substring(0,path.length()-2);
          File file= null;
          File dirFile=null;
          FileOutputStream fos=null;
          HttpURLConnection httpCon = null;
          URLConnection  con = null;
          URL urlObj=null;
          InputStream in =null;
          byte[] size = new byte[1024];
          int num=0;
          try {
              String downloadName= url.substring(url.lastIndexOf("/")+1);
              dirFile = new File(path);
              if(!dirFile.exists() && path.length()>0){
                  if(dirFile.mkdir()){
                      sop("creat document file \""+path.substring(0,path.length()-1)+"\" success...\n");
                  }
              }else{
                  file = new File(path+downloadName);
                  fos = new FileOutputStream(file);
                  if(url.startsWith("http")){
                      urlObj = new URL(url);
                      con = urlObj.openConnection();
                      httpCon =(HttpURLConnection) con;
                      int  responseCode = httpCon.getResponseCode();
                      if(responseCode == 200){
                          in = httpCon.getInputStream();
                          while((num=in.read(size)) != -1){
                              for(int i=0;i<num;i++)
                                  fos.write(size[i]);
                          }
                      }else {
                        System.out.println("状态码："+responseCode+" 地址："+url);
                    }
                  }
              }
          }catch (FileNotFoundException notFoundE) {
              sop("找不到该网络图片....");
          }catch(NullPointerException nullPointerE){
              sop("找不到该网络图片....");
          }catch(IOException ioE){
              sop("产生IO异常.....");
          }catch (Exception e) {
              e.printStackTrace();
          }finally{
              try {
                  if(fos!=null){
                      fos.close();
                  }
              } catch (Exception e) {
                  e.printStackTrace();
              }
          }
      }
}

其中，关键点在于获取图片img标签的正则表达式和图片的链接地址

String reg = "<img.*src=(.*?)[^>]*?>";
String reg2 = "src\\s*=\\s*\"?(.*?)(\"|>|\\s+)";

运行结果：