Issue with writing a List into CSV file using CSVWriter

Question

I have the following method to write a list into a CSV file using CSVWriter. Unfortunately, it does not separate them by comma which make them messy when I open it in Excel. How can I modify it?

   private void generateCSV(List<String> dataset) throws IOException {
        CSVWriter writer = null;
        JFileChooser chooser = new JFileChooser();
        chooser.setAcceptAllFileFilterUsed(true);
        if (chooser.showSaveDialog(chooser) == JFileChooser.APPROVE_OPTION) {
            File f = chooser.getSelectedFile();
            String file_name = f.toString();
            if (!(file_name.endsWith(".csv"))) {
                file_name += ".csv";
            }
            writer = new CSVWriter(new FileWriter(f));
            for(int i=0; i< dataset.size(); i++){
                String[] str = new String[] {dataset.get(i)};
                writer.writeNext(str);
            }

        } else {
            return;
        }
        writer.close();
    }

Answer 1

You're creating a String[] for each element on your dataset in your for loop and then writing one element per each line with writeNext() . So they are not comma separated because it's just one element per line, using the line separator at the end of each line.

I think that this is what you want. Am I right?

private void generateCSV(List<String> dataset) throws IOException {
    CSVWriter writer = null;
    JFileChooser chooser = new JFileChooser();
    chooser.setAcceptAllFileFilterUsed(true);
    if (chooser.showSaveDialog(chooser) == JFileChooser.APPROVE_OPTION) {
        File f = chooser.getSelectedFile();
        String file_name = f.toString();
        if (!(file_name.endsWith(".csv"))) {
            file_name += ".csv";
        }
        writer = new CSVWriter(new FileWriter(f));
        String[] str = new String[dataset.size()];
        for (int i = 0; i < dataset.size(); i++) {
            str[i] = dataset.get(i);
        }
        writer.writeNext(str);

    } else {
        return;
    }
    writer.close();
}