Java Swing - Remembering JFileChooser Location by using Java Util Preferences API

Following example shows how to use java.util.prefs to remember JFileChooser last location.

Using Preferences

Following is a helper enum class which does Preferences API handling:

package com.logicbig.example;

import java.util.prefs.Preferences;

public enum AppPrefs {
  FileLocation;
  private static Preferences prefs = Preferences.userRoot()
                                        .node(AppPrefs.class.getName());

  String get(String defaultValue) {
      return prefs.get(this.name(), defaultValue);
  }

  void put(String value) {
      prefs.put(this.name(), value);
  }
}

Main class

public class ExampleMain {
  public static void main(String[] args) {
      JFrame frame = createFrame();
      JLabel fileLabel = new JLabel();

      JButton openFileBtn = new JButton("Open File");
      openFileBtn.addActionListener(ae -> chooseFile(fileLabel, frame));

      JPanel panel = new JPanel();
      panel.add(openFileBtn);
      frame.add(panel, BorderLayout.NORTH);
      frame.add(fileLabel);
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
  }

  private static void chooseFile(JLabel fileLabel, JFrame frame) {
      JFileChooser fileChooser = new JFileChooser();
      String location = AppPrefs.FileLocation.get(System.getProperty("user.home"));
      fileChooser.setCurrentDirectory(new File(location));

      int returnValue = fileChooser.showOpenDialog(frame);
      if (returnValue == JFileChooser.APPROVE_OPTION) {
          File selectedFile = fileChooser.getSelectedFile();
          fileLabel.setText(selectedFile.getAbsolutePath());
          AppPrefs.FileLocation.put(selectedFile.getParentFile().getAbsolutePath());
      }
  }

  private static JFrame createFrame() {
      JFrame frame = new JFrame("JTree Remembering File Chooser location via Java Prefs");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setSize(new Dimension(500, 400));
      return frame;
  }
}

Output

The file location is remembered even after application restart.

Example Project

Dependencies and Technologies Used:

• JDK 10
• Maven 3.5.4