newnotepad.java

基础性的JAVA源代码

package exec.day1016;
import java.awt.*;
import javax.swing.*;
import javax.swing.filechooser.FileFilter;
import java.io.*;
import java.awt.event.*;
public class NewNotePad extends JFrame implements ActionListener{
	private JTextArea area;
	private JScrollPane jsp;
	private Font font;
	private JMenuBar bar;//菜单条
	private JMenu file;//菜单
	private JMenuItem open;//菜单项
	private JMenuItem save;
	private JMenuItem color;
	private JMenuItem exit;
	
	public void init(){
		font = new Font("楷体",Font.BOLD,20);
		this.setTitle("NotePad");
		//中间添加多行文本域
		area = new JTextArea();
		area.setFont(font);
		jsp = new JScrollPane(area);
		this.add(jsp);
		
		//菜单条部分
		bar = new JMenuBar();
		file = new JMenu("文件");
		open = new JMenuItem("打开");
		save = new JMenuItem("保存");
		color = new JMenuItem("颜色");
		exit = new JMenuItem("退出");
		//把菜单项添加到菜单上
		file.add(open);
		file.add(save);
		file.add(color);
		//添加分割线
		file.addSeparator();
		file.add(exit);
		//把菜单添加到菜单条上
		bar.add(file);
		//把菜单条添加到顶层容器中
		this.setJMenuBar(bar);
	}
	
	public void eventHandle(){
		open.addActionListener(this);
		save.addActionListener(this);
		color.addActionListener(this);
		exit.addActionListener(this);
	}
	class FileFilterTest extends FileFilter{
		private String name;//文本文件(*.txt)
		public FileFilterTest(String name){
			this.name = name;
		}
		public boolean accept(File f){
			if(f.isDirectory()){
				return true;
			}
			int startIndex = name.indexOf("(*.");
			String sub = name.substring(startIndex+2,name.length()-1);
			String fileName = f.getName();
//			System.out.println(sub);
//			System.out.println(fileName);
			return fileName.endsWith(sub);
		}
		public String getDescription(){
			return name;
		}
	}
	public void actionPerformed(ActionEvent e){
		String s = e.getActionCommand();
		if(s.equals("打开")){
			area.setText("");
			//构建文件选择器
			JFileChooser fc = new JFileChooser();
			//打开文件选择对话框，并指定父容器
//			JFrame f = new JFrame();
//			f.getContentPane()
			fc.addChoosableFileFilter(new FileFilterTest("文本文件(*.txt)"));
			fc.addChoosableFileFilter(new FileFilterTest("字节码文件(*.class)"));
			fc.addChoosableFileFilter(new FileFilterTest("Java源文件(*.java)"));
			fc.addChoosableFileFilter(new FileFilterTest("PPT文件(*.ppt)"));
			fc.showOpenDialog(this);
			//获取选中的文件
			File f = fc.getSelectedFile();
			if(f==null) return;
			
			//构建文件输入流
			FileReader fr = null;
			try {
				fr = new FileReader(f);
				//读取文件内容，并设置到多行文本域中
				int data = fr.read();
				while(data!=-1){
					area.append((char)data+"");
					data = fr.read();
				}		
			} catch (FileNotFoundException e1) {
				e1.printStackTrace();
			} catch (IOException e1) {
				e1.printStackTrace();
			} finally{
				try {
					fr.close();
				} catch (IOException e1) {
					e1.printStackTrace();
				}
			}
		}
		if(s.equals("保存")){
			JFileChooser fc = new JFileChooser();
			fc.showSaveDialog(this);
			File f = fc.getSelectedFile();
			if(f==null) return;
			//构建文件输出流
			FileWriter fw = null;
			try {
				fw = new FileWriter(f);
				fw.write(area.getText());
			} catch (IOException e1) {
				e1.printStackTrace();
			} finally{
				try {
					fw.close();
				} catch (IOException e1) {
					e1.printStackTrace();
				}
			}
		}
		if(s.equals("颜色")){
			//构建颜色选择器
			JColorChooser cc = new JColorChooser();
			//打开颜色选择对话框
			Color c = cc.showDialog(this,"请选择颜色",Color.RED);
			area.setForeground(c);
		}
		if(s.equals("退出")){
			System.exit(0);
		}
	}
	
	public void showMe(){
		this.setSize(800,700);
		this.setVisible(true);
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}
	
	public static void main(String args[]){
		NewNotePad n = new NewNotePad();
		n.init();
		n.eventHandle();
		n.showMe();
	}
}