binaryio.java

学习Java的一些基本课件和源代码 对于初学者很有帮助的

//BinaryIO.java
import javax.swing.*;
import java.awt.*;
import java.io.*;
import java.awt.event.*;

public class BinaryIO extends JFrame implements ActionListener{
	private JTextArea display=new JTextArea();
	private JButton read=new JButton("从文件读记录"),
					write=new JButton("产生随机记录");
	private JTextField filename=new JTextField(10);
	private JLabel prompt=new JLabel("文件名：",JLabel.RIGHT);
	private JPanel commands=new JPanel();
	
	public BinaryIO(){
		super("BinaryIO");
		read.addActionListener(this);
		write.addActionListener(this);
		commands.setLayout(new GridLayout(2,2,1,1));
		commands.add(prompt);
		commands.add(filename);
		commands.add(read);
		commands.add(write);
		display.setLineWrap(true);
		this.getContentPane().setLayout(new BorderLayout());
		this.getContentPane().add("North",commands);
		this.getContentPane().add(new JScrollPane(display));
		this.getContentPane().add("Center",display);
		
	}
	public void actionPerformed(ActionEvent e){
		String fileName=filename.getText();
		if(e.getSource()==read)
			readRecords(fileName);
		else
			writeRecords(fileName);
	}
	
	private void readRecords(String filename){
		try{
			DataInputStream in=new DataInputStream(new FileInputStream(filename));
			display.setText("Name     Age    pay\n");
			try{
				while(true){
					String name=in.readUTF();
					int age=in.readInt();
					double pay=in.readDouble();
					display.append(name+"    "+age+"   "+pay+"\n");
				}
			}catch(EOFException e){}
			finally{in.close();
			}
		}catch(FileNotFoundException e){
			display.setText("IOERROR: File not found:"+filename+"\n");
		}catch(IOException e){
			display.setText("IOERROR: "+e.getMessage()+"\n");
		}
	}
	
	private void writeRecords(String filename){
		try{
			DataOutputStream out=new DataOutputStream(new FileOutputStream(filename));
			for(int i=0;i<5;i++){
				String name="Name"+i;
				out.writeUTF("Name"+i);
				out.writeInt((int)(20+Math.random()*25));
				out.writeDouble(500.00+Math.random()*100);
			}
			out.close();
		}catch(IOException e){
			display.setText("IOERROR: "+e.getMessage()+"\n");
		}
	}
	
	public static void main(String args[]){
		BinaryIO bio=new BinaryIO();
		bio.setSize(240,200);
		bio.setVisible(true);
		bio.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

	}
}