Java Web Crawler for Downloading Sogou Image Search Results

The goal of this tutorial is to crawl Sogou Image Search, retrieve thousands of picture URLs matching a keyword (e.g., "美女"), and save the images locally.

Preparation involves constructing the request URL, for example: https://pic.sogou.com/pics?query=%E7%BE%8E%E5%A5%B3

By opening the page in a browser and inspecting the Network → XHR panel, you can see the API request used to fetch image data. Important query parameters include start (starting index), xml_len (number of items per request), and query (search keyword).

The implementation follows four main steps: (1) set the URL request parameters; (2) send the request and extract the picUrl field from the JSON response; (3) store all URLs in a list; (4) iterate the list and download each image using a thread pool for concurrency.

Below are the complete Java source files used in the project.

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 [email protected] * @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

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 [email protected] * @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) { 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) { 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)。 } 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(); } } }

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 [email protected] * 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 */ public static String get(String url) { return get(url, "UTF-8"); } public static Logger logger = LoggerFactory.getLogger(HttpClientUtils.class); /** http的get请求 */ 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 */ 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 */ public static String ajaxGet(String url, String charset) { HttpGet httpGet = new HttpGet(url); httpGet.setHeader("X-Requested-With", "XMLHttpRequest"); return executeRequest(httpGet, charset); } /** 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"); StringEntity stringEntity = new StringEntity(jsonString, charset); // 解决中文乱码问题 stringEntity.setContentEncoding(charset); stringEntity.setContentType("application/json"); httpPost.setEntity(stringEntity); 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); } } }

Running the program may not download every image on the first attempt due to network instability; re‑executing the crawler several times improves the overall success rate.

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