使用weka jar將csv轉換爲arff時出錯

Question

我想將csv文件轉換爲arff文件，並且我正在使用weka jar來執行操作，但它向我投擲nullpointerexception。下面是代碼

/* 
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    * and open the template in the editor. 
    */ 
     package Model; 

     import java.io.File; 
     import java.io.IOException; 
     import java.util.logging.Level; 
     import java.util.logging.Logger; 

     import weka.core.Instances; 
     import weka.core.converters.ArffSaver; 
     import weka.core.converters.CSVLoader; 

     /** 
     * 
     * @author sanketh 
     */ 
     public class testClass { 
      public void createArff(String Filename) { 
       try { 
        String path = Filename.substring(0, Filename.length() - 3); 
        System.out.println("new path:" + path); 
        String[] args = new String[2]; 
        args[0] = path + "csv"; 
        args[1] = path + "arff"; 
        // load CSV 
        CSVLoader loader = new CSVLoader(); 
        loader.setSource(new File(args[0])); 
        Instances data = loader.getDataSet(); 
     System.out.println(data); 
        // save ARFF 
        ArffSaver saver = new ArffSaver(); 
        saver.setInstances(data); 
        //saver.setFile(new File(args[1])); 
        saver.setFile(new File("h:\\abc.arff")); 
        saver.writeBatch(); 

       } catch (IOException ex) { 
        //System.out.println("Please try with some other test data!"); 
     //   attribMap.resultLog="Please try with some other test data!"; 
        Logger.getLogger(GenerateFile.class.getName()).log(Level.SEVERE, null, ex); 

       } 

      } 

      public static void main(String[] args) throws Exception { 
       String nepath="H:\\file.csv"; 
       testClass t1=new testClass(); 
       t1.createArff(nepath); 

      } 

     } 

這裏是堆棧跟蹤 它拋出我一個AERROR同時節省了ARFF回來... 幫助我在哪裏，我錯了？ 因爲我能夠顯示數據

Exception in thread "main" java.lang.NullPointerException 
     at java.io.Writer.<init>(Unknown Source) 
     at java.io.PrintWriter.<init>(Unknown Source) 
     at java.io.PrintWriter.<init>(Unknown Source) 
     at weka.core.converters.ArffSaver.writeBatch(ArffSaver.java:187) 
     at Model.testClass.createArff(testClass.java:39) 
     at Model.testClass.main(testClass.java:65) 

Answer 1

一行添加到您的保護對象它讀取來自CSV數據。

saver.setDestination(new File("F:\\abc.arff")); 

它會幫助你創建文件。