打开对话框和保存对话框（文件操作）

package cn.unit12.file;

import java.awt.Button;
import java.awt.Color;
import java.awt.FileDialog;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;

public class File7 {
	
	public static void main(String[] args) {
		File7frm frm = new  File7frm();

	}

}

class File7frm extends Frame implements ActionListener{
	FileDialog sv,op;
	Button btn1,btn2,btn3;
	TextArea tarea;
	File7frm(){
		super("打开和保存文件");
		setLayout(null);
		setBackground(Color.cyan);
		setSize(600,300);
		setVisible(true);
		btn1 = new Button("打开");
		btn2 = new Button("保存");
		btn3 = new Button("退出");
		
		tarea = new TextArea("");//创建文本区tarea
		add(btn1); add(btn2); add(btn3); add(tarea);
		tarea.setBounds(30, 50, 460, 220);
		btn1.setBounds(520, 60, 50, 30);
		btn2.setBounds(520, 120, 50, 30);
		btn3.setBounds(520, 180, 50, 30);
		//分别创建"打开"对话框和"保存"对话框
		op = new FileDialog(this,"打开",FileDialog.LOAD);
		sv = new FileDialog(this, "保存", FileDialog.S***E);
		
		btn1.addActionListener(this);
		btn2.addActionListener(this);
		btn3.addActionListener(this);
		addWindowListener(
			new WindowAdapter(){
				public void WindowClosing(WindowEvent e){
					System.exit(0);
				}
			}
		);	
		
	}
	
	public void actionPerformed(ActionEvent e){
		
		if(e.getSource()==btn1){
			String str;
			op.setVisible(true);
			try{
				File f1 = new File(op.getDirectory(),op.getFile());
				FileReader fr = new FileReader(f1);
				BufferedReader br = new BufferedReader(fr);
				tarea.setText("");//清空文本区
				while((str=br.readLine())!=null){
					tarea.append(str+'\n');
					fr.close();
				}
			}catch(Exception e1){
				
			}
		}
		
		if(e.getSource()==btn2){
			sv.setVisible(true);
			try{
				File f1 = new File(sv.getDirectory(),sv.getFile());
				FileWriter fw = new FileWriter(f1);
				BufferedWriter bw = new BufferedWriter(fw);
				String gt = tarea.getText();
				bw.write(gt,0,gt.length());
				bw.flush();
				fw.close();
			}catch(Exception e1){
				
			}
		}
		
		if(e.getSource()==btn3){
			System.exit(0);
		}
		
	}	
	
}