editordemo.java

本原码提供了Java程序设计中最为简单的一部分内容

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

//简单的文本编辑器

public class EditorDemo extends JFrame {
	JTextPane textPane = new JTextPane(); //文本窗格，编辑窗口
	JLabel statusBar = new JLabel(); //状态栏
	JFileChooser filechooser = new JFileChooser(); //文件选择器

	public EditorDemo() { //构造函数
		super("简单的文本编辑器");  //调用父类构造函数

		Action[] actions =  //Action数组,各种操作命令
			{
				new NewAction(),
				new OpenAction(),
				new SaveAction(),
				new CutAction(),
				new CopyAction(),
				new PasteAction(),
				new AboutAction(),
				new ExitAction()};

		setJMenuBar(createJMenuBar(actions));  //设置菜单栏
		Container container = getContentPane(); //得到容器
		container.add(createJToolBar(actions), BorderLayout.NORTH); //增加工具栏
		container.add(textPane, BorderLayout.CENTER); //增加文本窗格
		container.add(statusBar, BorderLayout.SOUTH); //增加状态栏

		setSize(330, 200); //设置窗口尺寸
		setVisible(true);  //设置窗口可视
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  //关闭窗口时退出程序
	}

	private JMenuBar createJMenuBar(Action[] actions) {  //创建菜单栏
		JMenuBar menubar = new JMenuBar(); //实例化菜单栏
		JMenu menuFile = new JMenu("文件"); //实例化菜单
		JMenu menuEdit = new JMenu("编辑");
		JMenu menuAbout = new JMenu("帮助");
		menuFile.add(new JMenuItem(actions[0])); //增加新菜单项
		menuFile.add(new JMenuItem(actions[1]));
		menuFile.add(new JMenuItem(actions[2]));
		menuFile.add(new JMenuItem(actions[7]));
		menuEdit.add(new JMenuItem(actions[3]));
		menuEdit.add(new JMenuItem(actions[4]));
		menuEdit.add(new JMenuItem(actions[5]));
		menuAbout.add(new JMenuItem(actions[6]));
		menubar.add(menuFile); //增加菜单
		menubar.add(menuEdit);
		menubar.add(menuAbout);
		return menubar; //返回菜单栏
	}

	private JToolBar createJToolBar(Action[] actions) { //创建工具条
		JToolBar toolBar = new JToolBar(); //实例化工具条
		for (int i = 0; i < actions.length; i++) { 
			JButton bt = new JButton(actions[i]); //实例化新的按钮
			bt.setRequestFocusEnabled(false); //设置不需要焦点
			toolBar.add(bt); //增加按钮到工具栏
		}
		return toolBar;  //返回工具栏
	}

	class NewAction extends AbstractAction { //新建文件命令
		public NewAction() {
			super("新建");
		}
		public void actionPerformed(ActionEvent e) {
			textPane.setDocument(new DefaultStyledDocument()); //清空文档
		}
	}

	class OpenAction extends AbstractAction { //打开文件命令
		public OpenAction() {
			super("打开");
		}
		public void actionPerformed(ActionEvent e) {
			int i = filechooser.showOpenDialog(EditorDemo.this); //显示打开文件对话框
			if (i == JFileChooser.APPROVE_OPTION) { //点击对话框中打开选项
				File f = filechooser.getSelectedFile(); //得到选择的文件
				try {
					InputStream is = new FileInputStream(f); //得到文件输入流
					textPane.read(is, "d"); //读入文件到文本窗格
				} catch (Exception ex) {
					ex.printStackTrace();  //输出出错信息
				}
			}
		}
	}

	class SaveAction extends AbstractAction {  //保存命令
		public SaveAction() {
			super("保存");
		}
		public void actionPerformed(ActionEvent e) {
			int i = filechooser.showSaveDialog(EditorDemo.this); //显示保存文件对话框
			if (i == JFileChooser.APPROVE_OPTION) {  //点击对话框中保存按钮
				File f = filechooser.getSelectedFile(); //得到选择的文件
				try {
					FileOutputStream out = new FileOutputStream(f);  //得到文件输出流
					out.write(textPane.getText().getBytes()); //写出文件				
				} catch (Exception ex) {
					ex.printStackTrace(); //输出出错信息
				}
			}
		}
	}

	class ExitAction extends AbstractAction { //退出命令
		public ExitAction() {
			super("退出");
		}
		public void actionPerformed(ActionEvent e) {
			System.exit(0);  //退出程序
		}
	}

	class CutAction extends AbstractAction {  //剪切命令
		public CutAction() {
			super("剪切");
		}
		public void actionPerformed(ActionEvent e) {
			textPane.cut();  //调用文本窗格的剪切命令
		} 
	}

	class CopyAction extends AbstractAction {  //拷贝命令
		public CopyAction() {
			super("拷贝");
		}
		public void actionPerformed(ActionEvent e) {
			textPane.copy();  //调用文本窗格的拷贝命令
		}
	}

	class PasteAction extends AbstractAction {  //粘贴命令
		public PasteAction() {
			super("粘贴");
		}
		public void actionPerformed(ActionEvent e) {
			textPane.paste();  //调用文本窗格的粘贴命令
		}
	}

	class AboutAction extends AbstractAction { //关于选项命令
		public AboutAction() {
			super("关于");
		}
		public void actionPerformed(ActionEvent e) {
			JOptionPane.showMessageDialog(EditorDemo.this, "简单的文本编辑器演示"); //显示软件信息
		}
	}

	public static void main(String[] args) {
		new EditorDemo();
	}

}