Java爬虫-使用爬虫下载千张美女图片！

目的

爬取搜狗图片上千张美女图片并下载到本地

准备工作

爬取地址：https://pic.sogou.com/pics?query=%E7%BE%8E%E5%A5%B3

分析

打开上面的地址，按F12开发者工具 – NetWork – XHR – 页面往下滑动XHR栏出现请求信息如下：

Request URL ： https://pic.sogou.com/napi/pc/searchList?mode=1&start=48&xml_len=48&query=%E7%BE%8E%E5%A5%B3

分析这段请求URL的主要几个参数：

start=48  表示从第48张图片开始检索

xml_len=48  从地48张往后获取48张图片

query=？    搜索关键词（例：美女，这里浏览器自动做了转码，不影响我们使用）

点击Respose，找个JSON格式器辅助过去看看。

JSON格式： https://www.bejson.com/

分析Respose返回的信息，可以发现我们想要的图片地址放在 picUrl里，

思路

通过以上分析，不难实现下载方法，思路如下：

1. 设置URL请求参数
2. 访问URL请求，获取图片地址
3. 图片地址存入List
4. 遍历List，使用线程池下载到本地

代码

SougouImgProcessor.java 爬取图片类

import com.alibaba.fastjson.JSONObject; import us.codecraft.webmagic.utils.HttpClientUtils; import victor.chang.crawler.pipeline.SougouImgPipeline; import java.util.ArrayList; import java.util.List; / * A simple PageProcessor. * * @author  
 * @since 0.1.0 */ public class SougouImgProcessor { private String url; private SougouImgPipeline pipeline; private List 
   
     dataList; private List 
    
      urlList; private String word; public SougouImgProcessor(String url,String word) { this.url = url; this.word = word; this.pipeline = new SougouImgPipeline(); this.dataList = new ArrayList<>(); this.urlList = new ArrayList<>(); } public void process(int idx, int size) { String res = HttpClientUtils.get(String.format(this.url, idx, size, this.word)); JSONObject object = JSONObject.parseObject(res); List 
     
       items = (List 
      
        )((JSONObject)object.get("data")).get("items"); for(JSONObject item : items){ this.urlList.add(item.getString("picUrl")); } this.dataList.addAll(items); } // 下载 public void pipelineData(){ // pipeline.process(this.urlList, word); // 单线程 pipeline.processSync(this.urlList, this.word); // 多线程 } public static void main(String[] args) { String url = "https://pic.sogou.com/napi/pc/searchList?mode=1&start=%s&xml_len=%s&query=%s"; SougouImgProcessor processor = new SougouImgProcessor(url,"美女"); int start = 0, size = 50, limit = 1000; // 定义爬取开始索引、每次爬取数量、总共爬取数量 for(int i=start;i 
        
       
      
     
   

SougouImgPipeline.java 图片下载类

 import java.io.File; import java.io.FileOutputStream; import java.io.InputStream; import java.net.URL; import java.net.URLConnection; import java.util.List; import java.util.Objects; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicInteger; / * Store results in files.
 * * @author 
 * @since 0.1.0 */ public class SougouImgPipeline { private String extension = ".jpg"; private String path; private volatile AtomicInteger suc; private volatile AtomicInteger fails; public SougouImgPipeline() { setPath("E:/pipeline/sougou"); suc = new AtomicInteger(); fails = new AtomicInteger(); } public SougouImgPipeline(String path) { setPath(path); suc = new AtomicInteger(); fails = new AtomicInteger(); } public SougouImgPipeline(String path, String extension) { setPath(path); this.extension = extension; suc = new AtomicInteger(); fails = new AtomicInteger(); } public void setPath(String path) { this.path = path; } / * 下载 * * @param url * @param cate * @throws Exception */ private void downloadImg(String url, String cate, String name) throws Exception { String path = this.path + "/" + cate + "/"; File dir = new File(path); if (!dir.exists()) { // 目录不存在则创建目录 dir.mkdirs(); } String realExt = url.substring(url.lastIndexOf(".")); // 获取扩展名 String fileName = name + realExt; fileName = fileName.replace("-", ""); String filePath = path + fileName; File img = new File(filePath); if(img.exists()){ // 若文件之前已经下载过，则跳过 System.out.println(String.format("文件%s已存在本地目录",fileName)); return; } URLConnection con = new URL(url).openConnection(); con.setConnectTimeout(5000); con.setReadTimeout(5000); InputStream inputStream = con.getInputStream(); byte[] bs = new byte[1024]; File file = new File(filePath); FileOutputStream os = new FileOutputStream(file, true); // 开始读取 写入 int len; while ((len = inputStream.read(bs)) != -1) { os.write(bs, 0, len); } System.out.println("picUrl: " + url); System.out.println(String.format("正在下载第%s张图片", suc.getAndIncrement())); } / * 单线程处理 * * @param data * @param word */ public void process(List 
    
      data, String word) { long start = System.currentTimeMillis(); for (String picUrl : data) { if (picUrl == null) continue; try { downloadImg(picUrl, word, picUrl); } catch (Exception e) { // e.printStackTrace(); fails.incrementAndGet(); } } System.out.println("下载成功: " + suc.get()); System.out.println("下载失败: " + fails.get()); long end = System.currentTimeMillis(); System.out.println("耗时：" + (end - start) / 1000 + "秒"); } / * 多线程处理 * * @param data * @param word */ public void processSync(List 
     
       data, String word) { long start = System.currentTimeMillis(); int count = 0; ExecutorService executorService = Executors.newCachedThreadPool(); // 创建缓存线程池 for (int i=0;i 
      
        { try { downloadImg(picUrl, word, finalName); } catch (Exception e) { // e.printStackTrace(); fails.incrementAndGet(); } }); count++; } executorService.shutdown(); try { if (!executorService.awaitTermination(60, TimeUnit.SECONDS)) { // 超时的时候向线程池中所有的线程发出中断(interrupted)。 // executorService.shutdownNow(); } System.out.println("AwaitTermination Finished"); System.out.println("共有URL: "+data.size()); System.out.println("下载成功: " + suc); System.out.println("下载失败: " + fails); File dir = new File(this.path + "/" + word + "/"); int len = Objects.requireNonNull(dir.list()).length; System.out.println("当前共有文件： "+len); long end = System.currentTimeMillis(); System.out.println("耗时：" + (end - start) / 1000.0 + "秒"); } catch (InterruptedException e) { e.printStackTrace(); } } / * 多线程分段处理 * * @param data * @param word * @param threadNum */ public void processSync2(List 
       
         data, final String word, int threadNum) { if (data.size() < threadNum) { process(data, word); } else { ExecutorService executorService = Executors.newCachedThreadPool(); int num = data.size() / threadNum; //每段要处理的数量 for (int i = 0; i < threadNum; i++) { int start = i * num; int end = (i + 1) * num; if (i == threadNum - 1) { end = data.size(); } final List 
        
          cutList = data.subList(start, end); executorService.execute(() -> process(cutList, word)); } executorService.shutdown(); } } } 
         
        
       
      
    

HttpClientUtils.java http请求工具类

import org.apache.http.Header; import org.apache.http.HttpEntity; import org.apache.http.NameValuePair; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.CloseableHttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.client.methods.HttpUriRequest; import org.apache.http.conn.ssl.SSLConnectionSocketFactory; import org.apache.http.conn.ssl.TrustStrategy; import org.apache.http.entity.StringEntity; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.message.BasicNameValuePair; import org.apache.http.ssl.SSLContextBuilder; import org.apache.http.util.EntityUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.net.ssl.HostnameVerifier; import javax.net.ssl.SSLContext; import javax.net.ssl.SSLSession; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.security.GeneralSecurityException; import java.security.cert.CertificateException; import java.security.cert.X509Certificate; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; / * @author  * Date: 17/3/27 */ public abstract class HttpClientUtils { public static Map 
  
    > convertHeaders(Header[] headers) { Map 
   
     > results = new HashMap 
    
      >(); for (Header header : headers) { List 
     
       list = results.get(header.getName()); if (list == null) { list = new ArrayList 
      
        (); results.put(header.getName(), list); } list.add(header.getValue()); } return results; } / * http的get请求 * * @param url */ public static String get(String url) { return get(url, "UTF-8"); } public static Logger logger = LoggerFactory.getLogger(HttpClientUtils.class); / * http的get请求 * * @param url */ public static String get(String url, String charset) { HttpGet httpGet = new HttpGet(url); return executeRequest(httpGet, charset); } / * http的get请求，增加异步请求头参数 * * @param url */ public static String ajaxGet(String url) { return ajaxGet(url, "UTF-8"); } / * http的get请求，增加异步请求头参数 * * @param url */ public static String ajaxGet(String url, String charset) { HttpGet httpGet = new HttpGet(url); httpGet.setHeader("X-Requested-With", "XMLHttpRequest"); return executeRequest(httpGet, charset); } / * @param url * @return */ public static String ajaxGet(CloseableHttpClient httpclient, String url) { HttpGet httpGet = new HttpGet(url); httpGet.setHeader("X-Requested-With", "XMLHttpRequest"); return executeRequest(httpclient, httpGet, "UTF-8"); } / * http的post请求，传递map格式参数 */ public static String post(String url, Map 
       
         dataMap) { return post(url, dataMap, "UTF-8"); } / * http的post请求，传递map格式参数 */ public static String post(String url, Map 
        
          dataMap, String charset) { HttpPost httpPost = new HttpPost(url); try { if (dataMap != null) { List 
         
           nvps = new ArrayList 
          
            (); for (Map.Entry 
           
             entry : dataMap.entrySet()) { nvps.add(new BasicNameValuePair(entry.getKey(), entry.getValue())); } UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(nvps, charset); formEntity.setContentEncoding(charset); httpPost.setEntity(formEntity); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } return executeRequest(httpPost, charset); } / * http的post请求，增加异步请求头参数，传递map格式参数 */ public static String ajaxPost(String url, Map 
            
              dataMap) { return ajaxPost(url, dataMap, "UTF-8"); } / * http的post请求，增加异步请求头参数，传递map格式参数 */ public static String ajaxPost(String url, Map 
             
               dataMap, String charset) { HttpPost httpPost = new HttpPost(url); httpPost.setHeader("X-Requested-With", "XMLHttpRequest"); try { if (dataMap != null) { List 
              
                nvps = new ArrayList 
               
                 (); for (Map.Entry 
                
                  entry : dataMap.entrySet()) { nvps.add(new BasicNameValuePair(entry.getKey(), entry.getValue())); } UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(nvps, charset); formEntity.setContentEncoding(charset); httpPost.setEntity(formEntity); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } return executeRequest(httpPost, charset); } / * http的post请求，增加异步请求头参数，传递json格式参数 */ public static String ajaxPostJson(String url, String jsonString) { return ajaxPostJson(url, jsonString, "UTF-8"); } / * http的post请求，增加异步请求头参数，传递json格式参数 */ public static String ajaxPostJson(String url, String jsonString, String charset) { HttpPost httpPost = new HttpPost(url); httpPost.setHeader("X-Requested-With", "XMLHttpRequest"); // try { StringEntity stringEntity = new StringEntity(jsonString, charset);// 解决中文乱码问题 stringEntity.setContentEncoding(charset); stringEntity.setContentType("application/json"); httpPost.setEntity(stringEntity); // } catch (UnsupportedEncodingException e) { // e.printStackTrace(); // } return executeRequest(httpPost, charset); } / * 执行一个http请求，传递HttpGet或HttpPost参数 */ public static String executeRequest(HttpUriRequest httpRequest) { return executeRequest(httpRequest, "UTF-8"); } / * 执行一个http请求，传递HttpGet或HttpPost参数 */ public static String executeRequest(HttpUriRequest httpRequest, String charset) { CloseableHttpClient httpclient; if ("https".equals(httpRequest.getURI().getScheme())) { httpclient = createSSLInsecureClient(); } else { httpclient = HttpClients.createDefault(); } String result = ""; try { try { CloseableHttpResponse response = httpclient.execute(httpRequest); HttpEntity entity = null; try { entity = response.getEntity(); result = EntityUtils.toString(entity, charset); } finally { EntityUtils.consume(entity); response.close(); } } finally { httpclient.close(); } } catch (IOException ex) { ex.printStackTrace(); } return result; } public static String executeRequest(CloseableHttpClient httpclient, HttpUriRequest httpRequest, String charset) { String result = ""; try { try { CloseableHttpResponse response = httpclient.execute(httpRequest); HttpEntity entity = null; try { entity = response.getEntity(); result = EntityUtils.toString(entity, charset); } finally { EntityUtils.consume(entity); response.close(); } } finally { httpclient.close(); } } catch (IOException ex) { ex.printStackTrace(); } return result; } / * 创建 SSL连接 */ public static CloseableHttpClient createSSLInsecureClient() { try { SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(new TrustStrategy() { @Override public boolean isTrusted(X509Certificate[] chain, String authType) throws CertificateException { return true; } }).build(); SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(sslContext, new HostnameVerifier() { @Override public boolean verify(String hostname, SSLSession session) { return true; } }); return HttpClients.custom().setSSLSocketFactory(sslsf).build(); } catch (GeneralSecurityException ex) { throw new RuntimeException(ex); } } } 
                 
                
               
              
             
            
           
          
         
        
       
      
     
    
  

运行

由于网络等原因，我们发现并不能全部下载成功，不过可以多次运行尝试，可以实现较高的下载成功率。

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