线程“main”中的异常 java.lang.NoClassDefFoundError: org/apache/http/conn/scheme/SchemeSocketFactory while Using Crawler4j
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Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/conn/scheme/SchemeSocketFactory while Using Crawler4j
提问by Raghavender Reddy
i am using Crawler4j Example code but i found that i got an exception.
我正在使用 Crawler4j 示例代码，但我发现我遇到了异常。
Here is my exception :
这是我的例外：
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/http/conn/scheme/SchemeSocketFactory
at LocalDataCollectorController.main(LocalDataCollectorController.java:24)
Caused by: java.lang.ClassNotFoundException: org.apache.http.conn.scheme.SchemeSocketFactory
Here is my code :
这是我的代码：
public static void main(String[] args) throws Exception {
String root Folder = "D:\";
int numberOfCrawlers = 5;
System.out.println("numberOfCrawlers"+numberOfCrawlers);
System.out.println(rootFolder);
CrawlConfig config = new CrawlConfig();
config.setCrawlStorageFolder(rootFolder);
config.setMaxPagesToFetch(10);
config.setPolitenessDelay(1000);
PageFetcher pageFetcher = new PageFetcher(config);
RobotstxtConfig robotstxtConfig = new RobotstxtConfig();
RobotstxtServer robotstxtServer = new RobotstxtServer(robotstxtConfig, pageFetcher);
CrawlController controller = new CrawlController(config, pageFetcher, robotstxtServer);
controller.addSeed("http://www.ohloh.net/p/crawler4j");
controller.start(LocalDataCollectorCrawler.class, numberOfCrawlers);
List<Object> crawlersLocalData = controller.getCrawlersLocalData();
long totalLinks = 0;
long totalTextSize = 0;
int totalProcessedPages = 0;
for (Object localData : crawlersLocalData) {
CrawlStat stat = (CrawlStat) localData;
totalLinks += stat.getTotalLinks();
totalTextSize += stat.getTotalTextSize();
totalProcessedPages += stat.getTotalProcessedPages();
}
System.out.println("Aggregated Statistics:");
System.out.println(" Processed Pages: " + totalProcessedPages);
System.out.println(" Total Links found: " + totalLinks);
System.out.println(" Total Text Size: " + totalTextSize);
}
}
回答by Kai
Download the HttpClientand add it to your build path.
下载HttpClient并将其添加到您的构建路径中。
There is also a package which contains all crawler4j dependencies in the download section. You should use this to avoid further problems.
在下载部分还有一个包含所有 crawler4j 依赖项的包。您应该使用它来避免进一步的问题。
回答by maksimov
The reason for NoClassDefFoundErroris always the same: you didn't supply the dependency class during runtime execution. In other words, when you ran your example, you didn't put HttpClient's JAR-file on the classpath. Do this and the problem will go away.
原因NoClassDefFoundError总是相同的：您没有在运行时执行期间提供依赖类。换句话说，当您运行示例时，您没有将 HttpClient 的 JAR 文件放在类路径上。这样做，问题就会消失。
