texteditor.java

ssd3的教程 是我们老师给我们的 纯英文 有兴趣的可以

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;

/**
 * Demonstrates the class {@link JFileChooser}. This class extends
 * class {@link @JPanel}.
 *
 * @author author name
 * @version 1.0.0
 */
public class TextEditor extends JPanel {

    /* Line separator */
    private final static String NEW_LINE =
        System.getProperty("line.separator");

    /* Standard error stream */
    private static PrintWriter  stdErr =
        new PrintWriter(System.err, true);


    private JButton  openButton;
    private JButton  saveButton;
    private TextArea  textArea;

    private JFileChooser  fileChooser;

    /**
     * Creates a window.
     *
     * @param args  not used.
     */
    public static void main(String[] args) {

        JFrame frame = new JFrame("TextEditor");

        frame.setContentPane(new TextEditor());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400,400);
        frame.setVisible(true);
    }

    /**
     * Creates a Graphical User Interface.
     */
    public TextEditor() {

        setBackground(Color.white);

        // Create the components
        openButton = new JButton("Open");
        saveButton = new JButton("Save");
        textArea = new TextArea();

        fileChooser = new JFileChooser();
        fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);

        // Register the listeners for the buttons
        openButton.addActionListener(new OpenButtonListener());
        saveButton.addActionListener(new SaveButtonListener());

        // Add components to the container
        setLayout(new BorderLayout());
        add(openButton, BorderLayout.NORTH);
        add(textArea, BorderLayout.CENTER);
        add(saveButton, BorderLayout.SOUTH);
    }

    /**
     * This inner class handles button clicks for the Open button.
     */
    class OpenButtonListener implements ActionListener {

        /**
         * Opens a text file.
         *
         * @param event  the event object.
         */
        public void actionPerformed(ActionEvent event)  {

            int result = fileChooser.showOpenDialog(null);

            if (result == JFileChooser.APPROVE_OPTION) {

                try {

                    File file = fileChooser.getSelectedFile();
                    BufferedReader  input =
                        new BufferedReader(new FileReader(file));

                    String  line = input.readLine();

                    while (line != null)  {
                        textArea.append(line + NEW_LINE);
                        line = input.readLine();
                    }
                    input.close();
                } catch (IOException ioe) {
                    stdErr.println(ioe.toString());
                }
            }
        }
    }

    /**
     * This inner class handles button clicks for the Save button.
     */
    class SaveButtonListener implements ActionListener {

        /**
         * Saves a text file.
         *
         * @param event  the event object.
         */
        public void actionPerformed(ActionEvent event) {

            int result = fileChooser.showSaveDialog(null);

            if (result == JFileChooser.APPROVE_OPTION) {

                try {

                    File file = fileChooser.getSelectedFile();
                    PrintWriter output =
                        new PrintWriter(new FileWriter(file));

                    output.print(textArea.getText());
                    output.close();
                } catch (IOException ioe) {
                    stdErr.println(ioe.toString());
                }
            }
        }
    }
}