java - 使用 weka.jar 将 CSV 文件转换为 ARFF

Question

对于我的项目，我使用 weka.jar。我正在使用以下代码将 CSV 文件转换为 ARFF:

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

import java.io.File;

public class CsvArffConverter
{

 public static void Convert(String sourcepath,String destpath) throws Exception
 {
 // load CSV
 CSVLoader loader = new CSVLoader();
 loader.setSource(new File(sourcepath));
 Instances data = loader.getDataSet();

 // save ARFF
 ArffSaver saver = new ArffSaver();
 saver.setInstances(data);
 saver.setFile(new File(destpath));
 saver.setDestination(new File(destpath));
 saver.writeBatch();
 }
 public static void main(String args[]) throws Exception
 {
 Convert("C:\\ad\\BSEIT.csv", "C:\\ad\\test.arff");

 }
}

但是，在执行时，出现以下错误:

Cannot create a new output file. Standard out is used.
Exception in thread "main" java.io.IOException: Cannot create a new output file (Reason: java.io.IOException: File already exists.). Standard out is used.
    at `enter code here`weka.core.converters.AbstractFileSaver.setDestination(AbstractFileSaver.java:421)
    at Predictor.CsvArffConverter.Convert(CsvArffConverter.java:29)
    at Predictor.CsvArffConverter.main(CsvArffConverter.java:34)

Answer 1

根据 weka mail list ，这个错误是文件问题，可能是权限问题。其他邮箱建议使用Java I/O approch保存 arff 文件。

This error is coming from the CSVSaver and indicates that it is unable 
to create the directory and/or file that you've specified. More than 
likely it is something to do with permissions on where it is trying to 
write to.

尝试以下代码。

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

import java.io.File;

public class CsvArffConverter
{
    public static void Convert(String sourcepath,String destpath) throws Exception
    {
        // load CSV
        CSVLoader loader = new CSVLoader();
        loader.setSource(new File(sourcepath));
        Instances dataSet = loader.getDataSet();

        // save ARFF
        BufferedWriter writer = new BufferedWriter(new FileWriter(destpath));
        writer.write(dataSet.toString());
        writer.flush();
        writer.close(); 
    }

    public static void main(String args[]) throws Exception
    {
        Convert("BSEIT.csv", "test.arff");
    }
}

如您所见，我使用相对路径。由于绝对路径写入可能会因为权限问题而被阻塞。