Thread: Getting extra lines when saving and loading into a JTextArea

I have made a SSCCE, it only has what I need. The problem happens to be replicated in this section, so my hunch was correct of where the problem was coming from. I think I might know the issue.

In the past, I had used the line break character to do line breaks, and the spacing was correct. However, I wanted a platform independent approach so I did System.getProperty("line.separator") instead and now the spacing is messed up. The new line and the System.getProperty() way both should work, with the latter being more portable. However, it is not reading it in properly.

I'm not sure yet if the problem is just caused by the read in, or if, when saved, it is messing up.

 
 
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.BufferedWriter;
import java.io.FileWriter;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import javax.swing.JFileChooser;
import javax.swing.JScrollPane;
 
public class IOWoes extends JFrame
{
 
   private JPanel contentPane;
   private JButton saveButton;
   private JButton loadButton;
   private JTextArea textArea;
 
   public IOWoes()
   {
 
      super("Why isn't this working?");
 
 
      contentPane = new JPanel(new BorderLayout());
 
      setContentPane(contentPane);
 
      textArea = new JTextArea(30, 30);
 
      JScrollPane jsp = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
 
      contentPane.add(jsp, BorderLayout.NORTH);
 
      JPanel lowerPanel = new JPanel(new BorderLayout());
 
      contentPane.add(lowerPanel, BorderLayout.SOUTH);
 
      saveButton = new JButton("Save");
 
      lowerPanel.add(saveButton, BorderLayout.WEST);
 
      loadButton = new JButton("Load");
 
      lowerPanel.add(loadButton, BorderLayout.EAST);
 
      saveButton.addActionListener(
            new ActionListener() {
 
               public void actionPerformed(ActionEvent e)
               {
 
                  JFileChooser chooser = new JFileChooser();
 
                  int option = chooser.showSaveDialog(null);
 
 
                  if (option == JFileChooser.APPROVE_OPTION)
                  {
 
                     File f = chooser.getSelectedFile();
 
 
                     writeToFile(f, textArea);
 
 
                  }
 
 
 
 
 
               }});
 
 
      loadButton.addActionListener(
            new ActionListener() {
 
               public void actionPerformed(ActionEvent e)
               {
 
                  JFileChooser chooser = new JFileChooser();
 
                  int option = chooser.showOpenDialog(null);
 
 
                  if (option == JFileChooser.APPROVE_OPTION)
                  {
 
                     File f = chooser.getSelectedFile();
 
 
 
                     readTextFromFile(textArea, f);
 
                  }
 
               }});
 
 
 
 
      setDefaultCloseOperation(EXIT_ON_CLOSE);
 
      setVisible(true);
 
   }
 
   public static void main(String[] args)
   {
 
      new IOWoes();
 
 
   }
 
 
 
 
   private void writeToFile(File f, JTextArea area)
   {
 
      try (
      java.io.BufferedWriter fileOut = new java.io.BufferedWriter(new java.io.FileWriter(f))) {
         area.write(fileOut);
      }
 
      catch (java.io.IOException ioe) {
         ioe.printStackTrace();
      }
 
   }
 
   private String readTextFromFile(JTextArea jtt, File f)
   {
 
      Scanner s = null;
      String readin = "";
 
      try
      {
         s = new Scanner(f);
      }
 
      catch(NullPointerException npe)
      {
 
 
      }
 
      catch(FileNotFoundException fnfe)
      {
         //JOptionPane.showMessageDialog(null, "File not found.", "Could not open selected file.", JOptionPane.ERROR_MESSAGE);
         return null;
 
      }
 
      while (s.hasNext())
      {
 
         readin = readin + s.nextLine() + System.getProperty("line.separator");
 
 
 
      }
 
      s.close();
 
 
      jtt.setText(readin);
 
 
 
      return readin;
 
 
 
   }
 
 
}

The problem is in one (or both) of the IO methods. I'm not sure what the save one is doing as it is a different approach than what I normally had used.

The System.getProperty("line.separator") String is for writing Strings to a disk file on an OS, not for using in a text area. Change to use "\n".

Thanks. So, what do you use then for a cross-platform line break thing? I heard that "\n" was only for Windows or something. That it wouldn't work on all systems.

(By the way, I did get it to work. I fixed the readTextFromFile() method to use the JTextArea read() method. Now it works.

I had heard that "\n" wasn't platform independent and looked up a way and came across the System.getProperty("line.separator").

I would use System.getProperty("line.separator") when writing to disk to be cross system compatible.

Originally Posted by Norm

I would use System.getProperty("line.separator") when writing to disk to be cross system compatible.

So, the "\n" is cross platform already.

Also, when you say "writing to disk", do you mean the hard drive, and hence that I shouldn't use JTextArea write() or whatever it was called to do it?

Or do you mean a separate disk outside of the hard drive? Like the kind they use to hold data at insurance companies and stuff like that.

By "disk" I meant some permanent medium outside of a computer's memory.

I don't think "\n" is cross platforms. I assume that what System.getProperty("line.separator") returns is cross platforms.