我正在尝试在java中为BasicCrawlController运行以下代码，但是我收到了一些错误：
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package edu.uci.ics.crawler4j.examples.basic;
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;
/**
* @author Yasser Ganjisaffar <lastname at gmail dot com>
*/
public class MyWebCrawler {
public static void main(String[] args) throws Exception {
if (args.length != 2) {
System.out.println("Needed parameters: ");
System.out.println("\t rootFolder (it will contain intermediate crawl data)");
System.out.println("\t numberOfCralwers (number of concurrent threads)");
return;
}
/*
* crawlStorageFolder is a folder where intermediate crawl data is
* stored.
*/
String crawlStorageFolder = args[0];
/*
* numberOfCrawlers shows the number of concurrent threads that should
* be initiated for crawling.
*/
int numberOfCrawlers = Integer.parseInt(args[1]);
CrawlConfig config = new CrawlConfig();
config.setCrawlStorageFolder(crawlStorageFolder);
/*
* Be polite: Make sure that we don't send more than 1 request per
* second (1000 milliseconds between requests).
*/
config.setPolitenessDelay(1000);
/*
* You can set the maximum crawl depth here. The default value is -1 for
* unlimited depth
*/
config.setMaxDepthOfCrawling(2);
/*
* You can set the maximum number of pages to crawl. The default value
* is -1 for unlimited number of pages
*/
config.setMaxPagesToFetch(1000);
/*
* Do you need to set a proxy? If so, you can use:
* config.setProxyHost("proxyserver.example.com");
* config.setProxyPort(8080);
*
* If your proxy also needs authentication:
* config.setProxyUsername(username); config.getProxyPassword(password);
*/
/*
* This config parameter can be used to set your crawl to be resumable
* (meaning that you can resume the crawl from a previously
* interrupted/crashed crawl). Note: if you enable resuming feature and
* want to start a fresh crawl, you need to delete the contents of
* rootFolder manually.
*/
config.setResumableCrawling(false);
/*
* 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/");
controller.addSeed("http://www.ics.uci.edu/~lopes/");
controller.addSeed("http://www.ics.uci.edu/~welling/");
/*
* 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(BasicCrawler.class, numberOfCrawlers);
}
}
错误是：
log4j:WARN No appenders could be found for logger (org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - Erroneous tree type: <any>
at mywebcrawler.MyWebCrawler.main(MyWebCrawler.java:107)
代码有什么问题？它完全从crawler4j的网站上复制而来！
答案 0 :(得分：1)
您缺少log4j属性文件。
答案 1 :(得分：0)
什么是BasicCrawler，是你自己的班级？你是如何定义它的，它是一个泛型类吗？你有没有忘记指定泛型类型？
答案 2 :(得分：0)
BasicCrawler是我从crawler4j文档中复制的一个类：
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;
public class BasicCrawler 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.aut.ac.ir/");
}
/**
* 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();
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);
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());
}
System.out.println("=============");
}
}