createsequentialfile.java

实现文件的问题 通过创建队列文件和用户存储记录来实现简单的银行功能

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.deitel.jhtp3.ch17.BankUI;
import com.deitel.jhtp3.ch17.BankAccountRecord;

public class CreateSequentialFile extends JFrame {
	private ObjectOutputStream output;
	private BankUI userInterface;
	private JButton enter, open;
	
	public CreateSequentialFile() {
		super( "Creating a sequential File of Objects");
		
		getContentPane().setLayout(new BorderLayout());
		userInterface = new BankUI();
		
		enter = userInterface.getDoTask();
		enter.setText("Enter");
		enter.setEnabled(false);
		enter.addActionListener(new ActionListener()
		                       {
		                       	public void actionPerformed(ActionEvent e)
		                       	{
		                       		addRecord();
		                       	}
		                       }
		                       );
		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e) {
				if(output != null) {
					addRecord();
					closeFile();
				}
				else {
					System.exit(0);
				}
			}
			}
			);
	    open = userInterface.getDoTask2();
	    
	    open.setText("Save As");
	    open.addActionListener(new ActionListener() {
	    	                    public void actionPerformed(ActionEvent e) {
	    	                    	openFile();
	    	                    }
	                           });
	    getContentPane().add(userInterface, BorderLayout.CENTER);
	    setSize(300, 200);
	    show();		
	}
	
	private void openFile() {
		JFileChooser fileChooser = new JFileChooser();
		fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
		
		int result = fileChooser.showSaveDialog(this);
		
		if(result == JFileChooser.CANCEL_OPTION) {
			return;
		}
		
		File fileName = fileChooser.getSelectedFile();
		
		if(fileName == null || fileName.getName().equals("")) {
			JOptionPane.showMessageDialog(this,"invalid File Name",
			                              "invalid file name",
			                              JOptionPane.ERROR_MESSAGE);
		}
		else {
			try {
				output = new ObjectOutputStream(new FileOutputStream(fileName));
				open.setEnabled(false);
				enter.setEnabled(true);
			}catch(IOException e) {
				JOptionPane.showMessageDialog(this,"Error opening File",
				                              "error",JOptionPane.ERROR_MESSAGE);
			}
		}
	}
	
	private void closeFile() {
		try {
			output.close();
			System.exit(0);
		}catch(IOException ex) {
			JOptionPane.showMessageDialog(this,"Error closing file",
			                             "Error",JOptionPane.ERROR_MESSAGE);
			System.exit(1);
		}
	}
	
	public void addRecord() {
		int accountNumber = 0;
		BankAccountRecord record;
		String fieldValues[] = userInterface.getFieldValues();
	
		if(!fieldValues[0].equals("")) {
			try {
				accountNumber = Integer.parseInt(fieldValues[0]);
				
				if(accountNumber > 0) {
					record = new BankAccountRecord (accountNumber,
					         fieldValues[1],fieldValues[2],
					         Double.parseDouble(fieldValues[3]));
					output.writeObject(record);
					output.flush();
				}
			}catch(NumberFormatException nfe) {
				JOptionPane.showMessageDialog(this,
				"Bad account number or balance",
				"invalid number format",
				JOptionPane.ERROR_MESSAGE);
			}catch(IOException io) {
				closeFile();
			}
		}
	}
	
	public static void main(String[] args) {
		new CreateSequentialFile();
	}
}