我现在已经4个小时了，我根本看不出自己做错了什么。我有两个文件：
MyCrawler.java
import edu.uci.ics.crawler4j.crawler.Page;
import edu.uci.ics.crawler4j.crawler.WebCrawler;
import edu.uci.ics.crawler4j.parser.HtmlParseData;
import edu.uci.ics.crawler4j.url.WebURL;
import java.util.List;
import java.util.regex.Pattern;
import org.apache.http.Header;
public class MyCrawler extends WebCrawler {
private final static Pattern FILTERS = Pattern.compile(".*(\\.(css|js|bmp|gif|jpe?g" + "|png|tiff?|mid|mp2|mp3|mp4"
+ "|wav|avi|mov|mpeg|ram|m4v|pdf" + "|rm|smil|wmv|swf|wma|zip|rar|gz))$");
/**
* You should implement this function to specify whether the given url
* should be crawled or not (based on your crawling logic).
*/
@Override
public boolean shouldVisit(WebURL url) {
String href = url.getURL().toLowerCase();
return !FILTERS.matcher(href).matches() && href.startsWith("http://www.ics.uci.edu/");
}
/**
* This function is called when a page is fetched and ready to be processed
* by your program.
*/
@Override
public void visit(Page page) {
int docid = page.getWebURL().getDocid();
String url = page.getWebURL().getURL();
String domain = page.getWebURL().getDomain();
String path = page.getWebURL().getPath();
String subDomain = page.getWebURL().getSubDomain();
String parentUrl = page.getWebURL().getParentUrl();
String anchor = page.getWebURL().getAnchor();
System.out.println("Docid: " + docid);
System.out.println("URL: " + url);
System.out.println("Domain: '" + domain + "'");
System.out.println("Sub-domain: '" + subDomain + "'");
System.out.println("Path: '" + path + "'");
System.out.println("Parent page: " + parentUrl);
System.out.println("Anchor text: " + anchor);
if (page.getParseData() instanceof HtmlParseData) {
HtmlParseData htmlParseData = (HtmlParseData) page.getParseData();
String text = htmlParseData.getText();
String html = htmlParseData.getHtml();
List<WebURL> links = htmlParseData.getOutgoingUrls();
System.out.println("Text length: " + text.length());
System.out.println("Html length: " + html.length());
System.out.println("Number of outgoing links: " + links.size());
}
Header[] responseHeaders = page.getFetchResponseHeaders();
if (responseHeaders != null) {
System.out.println("Response headers:");
for (Header header : responseHeaders) {
System.out.println("\t" + header.getName() + ": " + header.getValue());
}
}
System.out.println("=============");
}
}
Controller.java
package edu.crawler;
import edu.uci.ics.crawler4j.crawler.Page;
import edu.uci.ics.crawler4j.crawler.WebCrawler;
import edu.uci.ics.crawler4j.parser.HtmlParseData;
import edu.uci.ics.crawler4j.url.WebURL;
import java.util.List;
import java.util.regex.Pattern;
import org.apache.http.Header;
import edu.uci.ics.crawler4j.crawler.CrawlConfig;
import edu.uci.ics.crawler4j.crawler.CrawlController;
import edu.uci.ics.crawler4j.fetcher.PageFetcher;
import edu.uci.ics.crawler4j.robotstxt.RobotstxtConfig;
import edu.uci.ics.crawler4j.robotstxt.RobotstxtServer;
public class Controller
{
public static void main(String[] args) throws Exception
{
String crawlStorageFolder = "../data/";
int numberOfCrawlers = 7;
CrawlConfig config = new CrawlConfig();
config.setCrawlStorageFolder(crawlStorageFolder);
/*
* Instantiate the controller for this crawl.
*/
PageFetcher pageFetcher = new PageFetcher(config);
RobotstxtConfig robotstxtConfig = new RobotstxtConfig();
RobotstxtServer robotstxtServer = new RobotstxtServer(robotstxtConfig, pageFetcher);
CrawlController controller = new CrawlController(config, pageFetcher, robotstxtServer);
/*
* For each crawl, you need to add some seed urls. These are the first
* URLs that are fetched and then the crawler starts following links
* which are found in these pages
*/
controller.addSeed("http://www.ics.uci.edu/~welling/");
controller.addSeed("http://www.ics.uci.edu/~lopes/");
controller.addSeed("http://www.ics.uci.edu/");
/*
* Start the crawl. This is a blocking operation, meaning that your code
* will reach the line after this only when crawling is finished.
*/
controller.start(MyCrawler, numberOfCrawlers);
}
}
结构如下：
java/MyCrawler.java
java/Controller.java
jars/... --> all the jars crawler4j
我尝试使用以下命令在WINDOWS机器上编译它：
javac -cp "C:\xampp\htdocs\crawlcrowd\www\java\jars\*;C:\xampp\htdocs\crawlcrowd\www\java\*" MyCrawler.java
这很有效，我最终得到了：
java/MyCrawler.class
然而，当我输入：
javac -cp "C:\xampp\htdocs\crawlcrowd\www\java\jars\*;C:\xampp\htdocs\crawlcrowd\www\java\*" Controller.java
Controller.java:50: error: cannot find symbol
controller.start(MyCrawler, numberOfCrawlers);
^
symbol: variable MyCrawler
location: class Controller
1 error
所以，我觉得我不是在做一些我需要做的事情。将使这个新的可执行类成为＆＃34;意识到＆＃34; MyCrawler.class的。我试过在命令行javac部分中摆弄类路径。我也试过在我的环境变量中设置它......没有运气。
知道如何才能让它发挥作用吗？
更新
我从Google代码页本身获得了大部分代码。但我无法弄明白必须去哪里。即使我试试这个：
MyCrawler mc = new MyCrawler();
没有运气。不知何故，Controller.class不了解MyCrawler.class。
更新2
我不认为这很重要，因为问题显然是它无法找到课程，但无论哪种方式，这里都是＆＃34; CrawlController控制器＆＃34;的签名。取自here。
/**
* Start the crawling session and wait for it to finish.
*
* @param _c
* the class that implements the logic for crawler threads
* @param numberOfCrawlers
* the number of concurrent threads that will be contributing in
* this crawling session.
*/
public <T extends WebCrawler> void start(final Class<T> _c, final int numberOfCrawlers) {
this.start(_c, numberOfCrawlers, true);
}
我实际上正在通过一个＆＃34;爬虫＆＃34;因为我正在传递＆＃34; MyCrawler＆＃34;。问题是应用程序不知道MyCrawler是什么。
答案 0 :(得分：1)
有几件事情浮现在脑海中：
你的MyCrawler是否扩展了edu.uci.ics.crawler4j.crawler.WebCrawler？
public class MyCrawler extends WebCrawler
您是否将MyCrawler.class（即作为类）传入controller.start？
controller.start(MyCrawler.class, numberOfCrawlers);
为了让控制器编译和运行，需要满足这两个要求。此外，Crawler4j在这里有一些很好的例子：
这两个类将立即编译并运行（即BasicCrawlController），因此如果您遇到任何问题，它将是一个很好的起点。
答案 1 :(得分：0)
start（）的参数应该是爬网程序的类和数量。当您传入搜寻器对象而不是搜寻器类时，它会引发错误。使用如下所示的启动方法，它应该可以工作
controller.start(MyCrawler.class, numberOfCrawlers)
答案 2 :(得分：-1)
在这里，您要传递一个类名MyCrawler作为参数。
controller.start(MyCrawler, numberOfCrawlers);
我认为类名不应该是参数。
我也在爬行一点点工作！