Package edu.uci.ics.crawler4j.examples.basic

Source Code of edu.uci.ics.crawler4j.examples.basic.BasicCrawlController

/**
* 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 BasicCrawlController {

  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);
  }
}
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