openfile.java

java应用举例2

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

public class OpenFile{
	public static void main(String args[]){ 
		MyDialog dialog=new MyDialog(); 
	}
}

class  MyDialog extends Frame implements ActionListener{ 
	FileDialog saveDialog,loadDialog;
	MenuBar menubar;
	Menu menu;
	MenuItem item1,item2;
	TextArea text;
	BufferedReader in;  
	FileReader reader;
	BufferedWriter out; 
	FileWriter tofile;

	MyDialog()	{  
		super("文件输入输出流");     
		setSize(100,70);               
		setVisible(true);    
		menubar=new MenuBar();   
		menu=new Menu("文件"); 
		item1=new MenuItem("打开文件");
		item2=new MenuItem("保存文件"); 
		item1.addActionListener(this); 
		item2.addActionListener(this);
		menu.add(item1);
		menu.add(item2); 
		menubar.add(menu);  
		setMenuBar(menubar);   
		
		saveDialog=new FileDialog(this,"保存文件话框",FileDialog.SAVE);
		saveDialog.setVisible(false);

		loadDialog=new FileDialog(this,"打开文件话框",FileDialog.LOAD);
		loadDialog.setVisible(false);

		saveDialog.addWindowListener(new WindowAdapter(){
		  public void windowClosing(WindowEvent e){
		      saveDialog.setVisible(false);}
		});
		loadDialog.addWindowListener(new WindowAdapter(){
		  public void windowClosing(WindowEvent e){
		      loadDialog.setVisible(false);}
		});
		addWindowListener(new WindowAdapter() {
		  public void windowClosing(WindowEvent e){
		      setVisible(false);System.exit(0);}
		});

		text=new TextArea(10,10);
		text.setBackground(Color.cyan);
		add(text,"Center");
	}

	public void actionPerformed(ActionEvent e) 	{ 
		if(e.getSource()==item1){  
			loadDialog.setVisible(true);
			String s;

			try {
				File file=new File(loadDialog.getDirectory(),loadDialog.getFile());
				reader=new FileReader(file);
				in=new BufferedReader(reader);
				while((s=in.readLine())!=null)
					text.append(s+'\n'); 
			}
			catch(FileNotFoundException e1){
			}
			catch(IOException e2){
			}

			try {in.close();
				reader.close();
			}
			catch(IOException exp){
			} 
		}
		else if(e.getSource()==item2){
			saveDialog.setVisible(true);

			try {
				File file=new File(saveDialog.getDirectory(),saveDialog.getFile());
				tofile=new FileWriter(file);
				out=new BufferedWriter(tofile);
				out.write(text.getText(),0,(text.getText()).length());
				out.flush();
			}
			catch(FileNotFoundException e1){
			}
			catch(IOException e2){
			}

			try {out.close();
				tofile.close();
			}
			catch(IOException exp){
			} 
		}
	} 
}