删除文件

import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class DeleteFile extends JFrame{
    private JTextField cmdField;
    private Container container;
    public DeleteFile(){
        super("删除文件");
        Container container = getContentPane();
        cmdField = new JTextField(20);
        JButton delete = new JButton("删除");
        delete.addActionListener(new DeleteHandler());
        
        container.setLayout(new FlowLayout());
        container.add(cmdField);
        container.add(delete);
        
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        getRootPane().setDefaultButton(delete);
        pack();
        setResizable(false);
        
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
        Dimension frameSize = getSize();
        setLocation((screenSize.width - frameSize.width)/2,
                (screenSize.height - frameSize.width)/2);
        
        setVisible(true);
    }
    
    public static void main(String[] args) {
        new DeleteFile();
    }
    
    private class DeleteHandler implements ActionListener{
        public void actionPerformed(ActionEvent event){
            String command = cmdField.getText().trim();
            if(command.indexOf("delete")==-1){
                JOptionPane.showMessageDialog(container, "您输入的命令有误");
            }
            command = command.substring(6).trim();
            

            File file = new File(command);
            if(!file.isFile()){
                JOptionPane.showMessageDialog(container, "您输入的命令中不含文件名或无此文件");
                return;
            }
            
            file.delete();
            JOptionPane.showMessageDialog(container, "删除成功");
        }
    }
}