Java File类提供的方法与操作

File file = new File("d:/1.txt");

public class FileTest{
	public static void main(String[]args){
		File file = new File("world.txt");
		try{
			FileOutputStream out = new FileOutputStream(file);
			byte buy[] = "我有一头小毛驴，我从来也不骑。".getBytes();
			out.write(buy);
			out.close();
		} catch(Exception e) {
			e.printStackTrace();
		}
		try{
			//创建FileInputStream类对象
			FileInputStream in = new FileInputStream(file);
			byte byt[] = new byte[1024]; //创建byte数组
			int len = in.read(byt); //从文件中读取信息
			System.out.println("文件中的信息是：" + new String(byt, 0, len))
			in.close();
		} catch(Exception e) {
			e.printStackTrace();
		}
	}
}

public class Ftest extends JFrame{
	private static final long serialVersionUID = 1L;
	private JPanel jContentPane = null; //创建面板对象
	private JTextArea jTextArea = null; //创建文本域对象
	private JPanel controlPanel = null; //创建面板对象
	private JButton openButton = null; //创建按钮对象
	private JButton closeButton = null; //创建按钮对象
	private JButton getOpenButton(){
		if(openButton == null){
			openButton = new JButton();
			openButton.setText("写入文件"); //修改按钮的提示信息
			openButton.addActionListener(new ActionListener(){
				//按钮的单机事件
				public void actionPerformed(ActionEvent e){
					File file = new File("world.txt"); //创建文件对象
					try{
						FileWriter out = new FileWriter(file); //创建FileWriter对象
						String s = jTextArea.getText(); //获取文本域中文本
						out.write(s); //将信息写入磁盘文件
						out.close(); //将流关闭
					catch(Exception e1){
						e1.printStackTrace();
					}
				}
			});
		}
		return openButton;
	}
	private JButton getCloseButton(){
		if(closeButton == null){
			closeButton = new JButton();
			closeButton.setText("读取文件"); //修改按钮的提示信息
			closeButton.addActionListener(new ActionListener(){
				//按钮的单击事件
				public void actionPerformed(ActionEvent e){
					File file = new File("world.txt"); //创建文件对象
					try{
						FileReader in = new FileReader(file); //创建FileReader对象
						char byt[] = new char[1024]; //创建char型数组
						int len = in.read(byt); //将字节读入数组
						jTextArea.setText(new String(byt, 0, len)); //设置文本域的显示信息
						in.close(); //关闭流
					}catch(Exception e1){
						e1.printStackTrace();
					}
				}
			});
		}
		return closeButton;
	}
	public Ftest(){
		super();
		initialize();
	}
	private void initilize(){
		this.setSize(300,200);
		this.setContentPane(getJContentPane());
		this.setTitle("JFrame");
	}
	private JPanel getJContentPane(){
		if(jContentPane == null){
			jContentPane = new JPanel();
			jContentPane.setLayout(new BorderLayout());
			jContentPane.add(getJTextArea(), BorderLayout.CENTER);
			jContentPane.add(getControlPanel(),BorderLayout.SOUTH);
		}
		return jContentPane;
	}
	public static void main(String[] args){ //主方法
		Ftest thisClass = new Ftest(); //创建本类对象
		thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		thisClass.setVisible(true); //设置该窗体的显示状态
	}
}