hello/java/samples/properties/swing2/MainFrame.java

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package propertiesswing2;

import java.awt.*;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

/**
 *
 * @author denis
 */
public class MainFrame extends JFrame{
    private Properties property;
    private File file;
    private JTextField urlField;
    private JTextField usernameField;
    private JTextField passwordField;
    
    public MainFrame(){
        setTitle("Properties");
        Container root = getContentPane();
        root.setLayout(new BorderLayout(20, 20));
        
        //Добавляем группу кнопок
        root.add(createButtons(), BorderLayout.NORTH);
        //Добавляем группу меток и текстовых полей
        root.add(createDataArea());
        
        
        setSize(800, 300);
        setDefaultCloseOperation(DISPOSE_ON_CLOSE);
        setLocationRelativeTo(null);
        setResizable(false);
        setVisible(true);
    }
    
    private JPanel createButtons(){
        JPanel panel = new JPanel(new FlowLayout());
        JButton loadButton = new JButton("LOAD");
        JButton saveButton = new JButton("SAVE");
        panel.add(loadButton);
        panel.add(saveButton);
        
        loadButton.addActionListener(e -> {
            loadProperties();
            if(property!=null){
                if (urlField!=null) urlField.setText(property.getProperty("URL", ""));
                if (usernameField!=null) usernameField.setText(property.getProperty("username", ""));
                if (passwordField!=null) passwordField.setText(property.getProperty("password", ""));
            }
        });
        
        saveButton.addActionListener(e -> {
            String url = urlField!=null ? urlField.getText() : "";
            String username = usernameField!=null ? usernameField.getText() : "";
            String password = passwordField!=null ? passwordField.getText() : "";
            if(property!=null){
                property.put("URL", url);
                property.put("username", username);
                property.put("password", password);
            }
            saveProperties();
        });
        
        return panel;
    }
    
    private JPanel createDataArea(){
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints constraints = new GridBagConstraints();
        
        JLabel urlLabel = new JLabel("URL:");
        urlField = new JTextField(50);
        
        constraints.gridx = 0;
        constraints.gridy = 0;
        panel.add(urlLabel, constraints);
        
        constraints.gridx = 1;
        constraints.gridy = 0;
        panel.add(urlField, constraints);
        
        JLabel usernameLabel = new JLabel("username:");
        usernameField = new JTextField(50);
        
        constraints.gridx = 0;
        constraints.gridy = 1;
        panel.add(usernameLabel, constraints);
        
        constraints.gridx = 1;
        constraints.gridy = 1;
        panel.add(usernameField, constraints);
        
        JLabel passwordLabel = new JLabel("password:");
        passwordField = new JTextField(50);
        
        constraints.gridx = 0;
        constraints.gridy = 2;
        panel.add(passwordLabel, constraints);
        
        constraints.gridx = 1;
        constraints.gridy = 2;
        panel.add(passwordField, constraints);
        
        return panel;
    }
    
    private void loadProperties(){
        property = new Properties();
        if(file==null) file = new File("C:\\PropDir\\prop2.properties");
        //Проверяем существование файла
        if(!file.exists()) { 
            try {
                file.createNewFile();
            } catch (IOException ex) {
                Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
            }
        } else {
            if(file.canRead()){
                try (FileReader reader = new FileReader(file)) {
                    property.load(reader);
                } catch (FileNotFoundException ex) {
                    Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
                } catch (IOException ex) {
                    Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
        }
    }
    
    private void saveProperties(){
        if(file==null) file = new File("C:\\PropDir\\prop2.properties");
        if(!file.exists()) try {
            file.createNewFile();
        } catch (IOException ex) {
            Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
        }
        if(file.canWrite()){
            try (FileWriter writer = new FileWriter(file)) {
                property.store(writer, null);
            } catch (IOException ex) {
                Logger.getLogger(MainFrame.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }
}