exam12_4.java

java学习课件

/* 程序名Exam12_4.java
 * 文件复制应用程序
 */
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Exam12_4 extends JFrame implements ActionListener
{
  JTextField source=new JTextField();
  JTextField copy=new JTextField();
  JButton exit=new JButton("退出");
  JButton run=new JButton("复制");
  public Exam12_4()
  {
  	Container pane=this.getContentPane();
  	pane.setLayout(new GridLayout(0,2));
  	pane.add(new JLabel("源文件名"));
  	pane.add(source);
  	pane.add(new JLabel("备份文件名"));
  	pane.add(copy);
  	pane.add(exit);
  	pane.add(run);
  	exit.addActionListener(this);
  	run.addActionListener(this);
  	this.setTitle("文件复制示例");
  	this.setSize(300,200);
  	this.setDefaultCloseOperation(3);
  	this.setVisible(true); 
  }
  public void actionPerformed(ActionEvent evt)
  {
    Object obj=evt.getSource();
    if(obj==exit) System.exit(0);
    if(obj!=run) return;
    byte byteArray[]=new byte[128]; //定义字节数组
    String ss="文件复制完成!!!";
    try  //捕获I/O错误
    { 
     FileInputStream file1=new FileInputStream(source.getText());//创建对象
     FileOutputStream file2=new FileOutputStream(copy.getText());
     int n=file1.read(byteArray); //从文件中输入字节数据放入数组中
     while(n!=-1)
     { 
       file2.write(byteArray,0,n);  //将字节数组写入流中
       n=file1.read(byteArray); //从文件中输入字节数据放入数组中
     }
    }
    catch(IOException e)
    {
      ss=e.toString(); //输出出错信息
    }
    JOptionPane.showMessageDialog(null,ss,"操作信息",1);
  }
  public static void main(String [] args)
  {
    new Exam12_4();
  }
}