最简单的网络爬虫(用到了htmlparser,httpClient)

目录结构

 

第一步：

com.webcrawler.util.Queue.java

package com.webcrawler.util;import java.util.LinkedList;@SuppressWarnings("unchecked")public class Queue {private LinkedList queue = new LinkedList(); public void enQueue(Object t) {queue.add(t);}public Object deQueue() {return queue.removeFirst();}public boolean contains(Object t) {return queue.contains(t);}public boolean empty() {return queue.isEmpty();}}

 

第二步：

com.webcrawler.util.LinkQueue.java

package com.webcrawler.util;import java.util.HashSet;import java.util.Set;public class LinkQueue {@SuppressWarnings("unchecked")private static Set visitedUrl = new HashSet();private static Queue unVisitedUrl = new Queue();public static Queue getUnVisitedUrl() {return unVisitedUrl;}public static void addVisitedUrl(String url) {visitedUrl.remove(url);}public static void removeVisitedUrl(String url) {visitedUrl.remove(url);}public static Object unVisitedUrlDeQueue() {return unVisitedUrl.deQueue();}public static void addUnvisitedUrl(String url) {if(url != null && !url.trim().equals("")&& !visitedUrl.contains(url)&& !unVisitedUrl.contains(url)) {unVisitedUrl.enQueue(url);}}public static int getVisitedUrlNum() {return visitedUrl.size();}public static boolean unVisitedUrlsEmpty() {return unVisitedUrl.empty();}}

 

第三步：

com.webcrawler.util.LinkFilter.java

package com.webcrawler.util;public interface LinkFilter {public boolean accept(String url);}

 

第四步：

com.webcrawler.util.HtmlParserTool.java

package com.webcrawler.util;import java.util.HashSet;import java.util.Set;import org.htmlparser.Node;import org.htmlparser.NodeFilter;import org.htmlparser.Parser;import org.htmlparser.filters.NodeClassFilter;import org.htmlparser.filters.OrFilter;import org.htmlparser.tags.LinkTag;import org.htmlparser.util.NodeList;import org.htmlparser.util.ParserException;public class HtmlParserTool {@SuppressWarnings("serial")public static Set<String> extracLinks(String url, LinkFilter filter) {Set<String> links = new HashSet<String> ();try {Parser parser = new Parser(url);parser.setEncoding("UTF-8");NodeFilter frameFilter = new NodeFilter() {@Overridepublic boolean accept(Node node) {if(node.getText().startsWith("frame src=")) {return true;}return false;}};OrFilter linkFilter = new OrFilter(new NodeClassFilter(LinkTag.class), frameFilter);NodeList list = parser.extractAllNodesThatMatch(linkFilter);for(int i=0; i<list.size(); i++) {Node tag = list.elementAt(i);if( tag instanceof LinkTag) {LinkTag link = (LinkTag) tag;String linkUrl = link.getLink();if(filter.accept(url)) {links.add(linkUrl);} else {String frame = tag.getText();int start = frame.indexOf("src=");if( start != -1) {frame = frame.substring(start);}int end = frame.indexOf(" ");String frameUrl = "";if(end == -1) {end = frame.indexOf(">");if(end-1 > 5) { frameUrl = frame.substring(5, end - 1);}}if(filter.accept(frameUrl)) {links.add(frameUrl);}}}}} catch (ParserException e) {e.printStackTrace();} return links;}}

 

第五步：

com.webcrawler.util.DownloadFile.java

package com.webcrawler.util;import java.io.DataOutputStream;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;import org.apache.commons.httpclient.HttpClient;import org.apache.commons.httpclient.HttpException;import org.apache.commons.httpclient.HttpStatus;import org.apache.commons.httpclient.methods.GetMethod;import org.apache.commons.httpclient.params.HttpMethodParams;public class DownloadFile {public String getFileNameByUrl(String url, String contentType) {url = url.substring(7);if(contentType.indexOf("html") != -1) {url = url.replaceAll("[//?/:*|<>/"]", "_") + ".html";return url;} else {return url.replaceAll("[//?/:*|<>/"]","_") + "." +contentType.substring(contentType.lastIndexOf("/") + 1);}}private void saveToLocal(byte[] data, String filePath) {try {DataOutputStream out = new DataOutputStream(new FileOutputStream(new File(filePath)));for(int i=0; i<data.length; i++) {out.write(data[i]);}out.flush();out.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}public String downLoadFile(String url) {String filePath = null;HttpClient httpClient = new HttpClient();//set time out httpClient.getHttpConnectionManager() .getParams() .setConnectionTimeout(5000);GetMethod getMethod = new GetMethod(url);getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 5000);getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler()); //retry//execute HTTP GET requesttry {getMethod.addRequestHeader("Content-Type", "text/html; charset=UTF-8"); int statusCode = httpClient.executeMethod(getMethod);if(statusCode != HttpStatus.SC_OK) {System.out.println("Method failed:" + getMethod.getStatusLine());filePath = null;}//execute HTTP contentbyte[] responseBody = getMethod.getResponseBody();File file = new File("temp");if(!file.exists()) {file.mkdir();}filePath = "temp//" + getFileNameByUrl(url, getMethod.getResponseHeader("Content-Type").getValue());System.out.println("---------"+url+"-------");saveToLocal(responseBody, filePath);} catch (HttpException e) {System.out.println("Please check you provided http address!");} catch (IOException e) {} catch (RuntimeException e) {System.out.println("error");}finally {getMethod.releaseConnection();}return filePath;}}

 

第六步：

com.webcrawler.test.MainCrawler.java

package com.webcrawler.test;import java.util.Set;import com.webcrawler.util.DownloadFile;import com.webcrawler.util.HtmlParserTool;import com.webcrawler.util.LinkFilter;import com.webcrawler.util.LinkQueue;public class MainCrawler {private void initCrawlerWithSeeds(String[] seeds) {for(int i=0; i<seeds.length; i++) {LinkQueue.addUnvisitedUrl(seeds[i]);}}public void crawling(String[] seeds) {LinkFilter filter = new LinkFilter() {@Overridepublic boolean accept(String url) {if(url.startsWith("http://www.zcib.edu.cn")) {return true;}return false;}};initCrawlerWithSeeds(seeds);while(!LinkQueue.unVisitedUrlsEmpty() && LinkQueue.getVisitedUrlNum()<=1000) {String visitUrl = (String) LinkQueue.unVisitedUrlDeQueue();if(visitUrl == null) {continue;}DownloadFile downLoader = new DownloadFile();downLoader.downLoadFile(visitUrl);LinkQueue.addVisitedUrl(visitUrl);Set<String> links = HtmlParserTool.extracLinks(visitUrl, filter);for(String link:links) {LinkQueue.addUnvisitedUrl(link);}}}public static void main(String[] args) {MainCrawler crawler = new MainCrawler();crawler.crawling(new String[]{"http://www.zcib.edu.cn"});}}

 

That's all.

 

所有jar包在

http://download.csdn.net/source/3136181