Weka软件包管理器更新错误的解决方法

     最近学习使用Weka，用的版本为3.7.9，想在上面安装libsvm用来分类，但是使用软件包管理器时总是跳出“ There was a problem establishing the package meta data cache.We'll try to use the repository directly.”的错误信息，详细信息如下：

java.net.UnknownHostException: weka.sourceforge.net         at java.net.AbstractPlainSocketImpl.connect(Unknown Source)         at java.net.PlainSocketImpl.connect(Unknown Source)         at java.net.SocksSocketImpl.connect(Unknown Source)         at java.net.Socket.connect(Unknown Source)         at sun.net.NetworkClient.doConnect(Unknown Source)         at sun.net.www.http.HttpClient.openServer(Unknown Source)         at sun.net.www.http.HttpClient.openServer(Unknown Source)         at sun.net.www.http.HttpClient.<init>(Unknown Source)         at sun.net.www.http.HttpClient.New(Unknown Source)         at sun.net.www.http.HttpClient.New(Unknown Source)         at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)         at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)         at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)         at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)         at org.pentaho.packageManagement.DefaultPackageManager.getRepositoryPackageMetaDataOnlyAsZip(Unknown Source)         at weka.core.WekaPackageManager.refreshCache(WekaPackageManager.java:821)         at weka.core.WekaPackageManager.establishCacheIfNeeded(WekaPackageManager.java:755)         at weka.gui.PackageManager$EstablishCache.doInBackground(PackageManager.java:285)         at weka.gui.PackageManager$EstablishCache.doInBackground(PackageManager.java:256)         at javax.swing.SwingWorker$1.call(Unknown Source)         at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)         at java.util.concurrent.FutureTask.run(Unknown Source)         at javax.swing.SwingWorker.run(Unknown Source)         at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)         at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)         at java.lang.Thread.run(Unknown Source)

网上查找，有说将libsvm的包放至Weka安装再更改runweka.ini文件的，这种方法貌似在较老版本的Weka中可以成功，但是我用这种方法在3.7.9中总是不能成功，后来看到可以添加PackageRepository.props文件（http://forums.pentaho.com/showthread.php?90698-exception-on-loading-Package-Manager），但是添加这个文件的文件夹即：$HOME\wekafiles\props\始终没找到，在链接http://datamining.xmu.edu.cn/bbs/forum.php?mod=viewthread&tid=120中zouquan提到了两个文件夹，即“C:\Users\Administrator\wekafiles   (windows7)”和“C:\Documents and Settings\Administrator\wekafiles   (XP)”，于是去查这个文件夹，里面果然有上面所要找的...\wekafiles\props\，于是新建文件PackageRepository.props，并在文件中添加weka.core.wekaPackageRepositoryURL=http://www.cs.waikato.ac.nz/ml/weka/packageMetaData，以上错误终于不再出现！