I/O流及文件

曾经终败给现在 2022-06-13 01:19 100阅读 0赞

最近在学I/O流和文件，看了书上的两个小程序，一个是文本文件读写应用小程序，一个是二进制读写应用小程序。

1、文本文件读写应用小程序

package IO流;
    
    import javax.swing.*;
    import java.awt.*;
    import java.io.*;
    import java.awt.event.*;
    
    public class TextFileIO extends JFrame implements ActionListener{
    
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	JTextArea content = new JTextArea();
    	JButton read = new JButton("读文件"),write = new JButton("写文件");
    	JTextField FileName = new JTextField(20);
    	JLabel prompt = new JLabel("输入文件名：",JLabel.RIGHT);
    	JPanel commands = new JPanel();
    	public TextFileIO(){
    		super("文本文件读写示例");           //设置窗体标题
    		read.addActionListener(this);
    		write.addActionListener(this);
    		commands.setLayout(new GridLayout(2,2,1,1));    //设置面板布局
    		commands.add(prompt);
    		commands.add(FileName);
    		commands.add(read);
    		commands.add(write);
    		this.getContentPane().setLayout(new BorderLayout());
    		this.getContentPane().add("North", commands);
    		this.getContentPane().add(new JScrollPane(content));
    		this.getContentPane().add("Center", content);
    	}
    	private void writeTextFile(JTextArea content, String fileName){
    		try {
    			FileWriter outStream = new FileWriter(fileName);
    			outStream.write (content.getText());
    			outStream.close();
    		} catch (Exception e) {
    			content.setText("IOERROR:" + e.getMessage() + "\n");
    			e.printStackTrace();
    		}
    	}
    
    	private void readTextFile(JTextArea content, String fileName){
    		try {
    			BufferedReader inStream = new BufferedReader(new FileReader(fileName));    //创建并打开流
    			String line = inStream.readLine();                 //读一行
    			while(line != null){                               //判断是否读完
    				content.append(line + '\n');               //显示一行
    				line = inStream.readLine();                //读下一行
    			}
    			inStream.close();                                  //关闭流
    		} catch (Exception e) {
    			content.setText("IOERROR:" + fileName + "NOT found\n");
    			e.printStackTrace();
    		}
    	}
    	public void actionPerformed(ActionEvent evt) {
    		String fileName = FileName.getText();
    		if (evt.getSource() == read) {
    			content.setText("");
    			readTextFile(content,fileName);
    		} else {
    			writeTextFile(content,fileName);
    		}
    	}
    	
    	public static void main(String args[]){
    		TextFileIO tf1 = new TextFileIO();
    		tf1.setSize(400,200);
    		tf1.setVisible(true);
    		tf1.addWindowListener(new WindowAdapter(){
    			public void windowClosing(WindowEvent e){
    				System.exit(0);
    			}
    		});
    	}
    }

运行结果图：

![Image 1][]

![Center][]

2、二进制读写应用小程序

//二进制读写应用小程序
    package IO流;
    
    import javax.swing.*;
    import java.awt.*;
    import java.io.*;
    import java.awt.event.*;
    
    
    public class BinaryFileIO extends JFrame implements ActionListener{
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	private JTextArea content = new JTextArea();
    	private JButton read = new JButton("读二进制文件"), write = new JButton("写二进制文件");
    	private JTextField name = new JTextField(10);
    	JLabel prompt = new JLabel("输入文件名：",JLabel.RIGHT);
    	JPanel commands = new JPanel();
    	public BinaryFileIO(){
    		super("二进制文件读写示例");
    		read.addActionListener(this);
    		write.addActionListener(this);
    		commands.setLayout(new GridLayout(2,2,1,1));
    		commands.add(prompt);
    		commands.add(name);
    		commands.add(read);
    		commands.add(write);
    		content.setLineWrap(true);
    		this.getContentPane().setLayout(new BorderLayout());
    		this.getContentPane().add("North", commands);
    		this.getContentPane().add(new JScrollPane(content));
    		this.getContentPane().add("Center", content);
    	}
    	private void readRecords (String fileName){
    		try {
    			DataInputStream in =new DataInputStream(new FileInputStream(fileName));
    			content.setText("姓名                 年龄                 工资\n");
    			try {
    				while(true){
    					String name = in.readUTF();
    					int age = in.readInt();
    					double pay = in.readDouble();
    					content.append(name + " " + age + " " + pay + "\n");
    				}
    				}catch(EOFException e){
    			} finally {
    				in.close();
    			}
    		}catch(FileNotFoundException e){
    			content.setText("IOERROR: File NOT Found: " + fileName + "\n");
    		}catch(IOException e){
    			content.setText("IOERROR: " + e.getMessage() + "\n");
    		}
    	}
    	private void writeRecords( String fileName ){
    		try {
    			DataOutputStream out =new DataOutputStream(new FileOutputStream(fileName));
    			for(int k = 0; k < 5; k++){
    				//String name = "Name" + k;
    				out.writeUTF("Name" + k);
    				out.writeInt((int)(20 + Math.random() * 25));
    				out.writeDouble(2500 + Math.random() * 2000);
    			}
    			out.close();
    		} catch (IOException e) {
    			content.setText("ERROR: " + e.getMessage() + "\n");
    		}
    	}
    	public static void main(String[] args) {
    		BinaryFileIO bio = new BinaryFileIO();
    		bio.setSize(400,200);
    		bio.setVisible(true);
    		bio.addWindowListener(new WindowAdapter(){
    			public void windowClosing(WindowEvent e){
    				System.exit(0);
    			}
    		});
    	}
    	
    	public void actionPerformed(ActionEvent e) {
    		String fileName = name.getText();
    		if (e.getSource() == read)
    			readRecords(fileName);
    		else writeRecords(fileName);
    	}
    }

运行结果图：

![Center 1][]

[Image 1]: 
[Center]: /images/20220613/dcae495793bb4432b6919d5f1fbe47e8.png
[Center 1]: /images/20220613/3b7e25f0756042f787cc5e176a705777.png