file cannot be deleted even after closing streams

Question

I'm trying to open a file from a URL, copy it to a temporary file, and then delete the temporary file when processing work is done. However, I am unable to delete the file. I have tried closing all streams, I have tried deleting with both deleteOnExit() method and the Delete() method. This is an excel file which I am working with. When I am not using an excel file, or more particularly the Workbook object as shown in my code below, the file deletes just fine. As soon as I pass my file to the workbookFactory.create() method, my file cannot be deleted by the code.

Here's the code below:

public class URLtoFileWriting {

/**
 * @param args the command line arguments
 * @throws java.io.IOException
 */

static File destinationFile;
public static void getFile() throws IOException {

    try {
        // TODO code application logic here

        URL fileURL = new URL("http://www.testURL.com/testfile.xlsx");
        URLtoFileWriting.destinationFile = File.createTempFile("remotefile",".xlsx");

        try {
            URLConnection URLconnection = fileURL.openConnection();
            InputStream inputStream = URLconnection.getInputStream();
            FileOutputStream fileoutputStream = new FileOutputStream(URLtoFileWriting.destinationFile);
            IOUtils.copy(inputStream, fileoutputStream);

            Workbook wb = WorkbookFactory.create(URLtoFileWriting.destinationFile);

            System.out.println(URLtoFileWriting.destinationFile.getAbsolutePath());
            inputStream.close();
            fileoutputStream.close();
            System.out.println("Deleted testWB?!" + URLtoFileWriting.destinationFile.delete());



        } catch (IOException ex) {
            Logger.getLogger(URLtoFileWriting.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InvalidFormatException ex) {
            Logger.getLogger(URLtoFileWriting.class.getName()).log(Level.SEVERE, null, ex);
        }


    } catch (MalformedURLException ex) {
        Logger.getLogger(URLtoFileWriting.class.getName()).log(Level.SEVERE, null, ex);
    }


}

}

All the imports I am using:

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.commons.io.IOUtils;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.usermodel.WorkbookFactory;

I suspect it has something to do with the workbookFactory.create() method, as deletion becomes impossible once I have passed the file to this method.

What am I doing wrong here?

UPDATE. I have come across a fix: You can pass the File to a FileInputStream, and then pass this stream to the WorkbookFactory.Create() method.

Updated code below to reflect this:

  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.net.MalformedURLException;
  import java.net.URL;
  import java.net.URLConnection;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  import org.apache.commons.io.IOUtils;
  import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
  import org.apache.poi.ss.usermodel.Workbook;
  import org.apache.poi.ss.usermodel.WorkbookFactory;


 public class URLtoFileWriting {

/**
 * @param args the command line arguments
 * @throws java.io.IOException
 */

static File destinationFile;
public static void getFile() throws IOException {

    try {
        // TODO code application logic here

        URL fileURL = new URL("http://www.testURL.com/testfile.xlsx");
        URLtoFileWriting.destinationFile = File.createTempFile("remotefile",".xlsx");

        try {
            URLConnection URLconnection = fileURL.openConnection();
            InputStream inputStream = URLconnection.getInputStream();
            FileOutputStream fileoutputStream = new FileOutputStream(URLtoFileWriting.destinationFile);
            IOUtils.copy(inputStream, fileoutputStream);

            FileInputStream FIS = new FileInputStream(URLtoFileWriting.destinationFile);
            Workbook wb = WorkbookFactory.create(FIS);
            FIS.close();
            inputStream.close();
            fileoutputStream.close();
            System.out.println(URLtoFileWriting.destinationFile);
            System.out.println(URLtoFileWriting.destinationFile.delete());



        } catch (IOException ex) {
            Logger.getLogger(URLtoFileWriting.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InvalidFormatException ex) {
            Logger.getLogger(URLtoFileWriting.class.getName()).log(Level.SEVERE, null, ex);
        }


    } catch (MalformedURLException ex) {
        Logger.getLogger(URLtoFileWriting.class.getName()).log(Level.SEVERE, null, ex);
    }


}

}

I hope this helps.

Answer 1

Find the solution here Close Filehandle for Workbook (apache poi).

Use NPOIFSFileSystem#close() or OPCPackage#close().

For more info have a look at the overloaded constructors of WorkbookFactory class.