我正在编写一个简单的银行程序，它为用户提供了一个非常简单的 GUI 来处理一个简单的银行账户，其中包含余额和所有者姓名等变量。因为该程序仅从单个银行帐户运行，所以每次启动程序时都会反序列化帐户（对象）。这就是我的问题所在：每次我的帐户对象被反序列化时，它都会变成null. 我试过四处寻找这个，结果却是空的。我该如何防止这种情况？我觉得这是一个比我想象的更容易解决的问题，但我只是不确定它为什么会发生。为什么account对象没有作为帐户返回？我将在下面发布这两个课程...
银行GUI类：
package GUIs;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ListSelectionModel;
import javax.swing.ScrollPaneConstants;
import javax.swing.UIManager;
public class BankGUI implements Serializable {
BankAccount account;
static BankGUI gui;
private void deserializeAccount() {
try {
ObjectInputStream objectStream2 = new ObjectInputStream(
new FileInputStream("bankAccounts.txt"));
Object acc = objectStream2.readObject();
account = (BankAccount) acc;
System.out.println("yes");
objectStream2.close();
} catch (Exception e) {
e.printStackTrace();
System.out.println("Nope.");
}
}
private void checkForNull() {
if (account == null) {
System.out.println("It's been nullified.");
} else {
System.out.println("It worked.");
}
}
public static void main(String[] args) {
System.out.println("");
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace();
}
gui = new BankGUI();
gui.deserializeAccount();
gui.checkForNull();
gui.displayGUI();
}
// all global components for JFrame
JTextArea statusArea;
JCheckBox isLockedCheckBox;
JList depositAmount;
JList withdrawAmount;
JButton depositButton;
JButton withdrawButton;
JButton saveAccountButton;
private void displayGUI() {
JFrame frame = new JFrame("Virtual Bank v3.3");
Integer[] intList = { 1, 2, 5, 10, 20, 50 };
JPanel rightPanel = new JPanel();
rightPanel.setLayout(new BoxLayout(rightPanel, BoxLayout.Y_AXIS));
rightPanel.setBackground(Color.GREEN);
JPanel centerPanel = new JPanel();
centerPanel.setBackground(Color.GREEN);
centerPanel.setLayout(new GridBagLayout());
frame.add(BorderLayout.CENTER, centerPanel);
frame.add(BorderLayout.EAST, rightPanel);
// add some JLabel's
JLabel depositAmountLabel = new JLabel("Deposit Amount:");
JLabel withdrawAmountLabel = new JLabel("Withdraw Amount:");
JLabel isLockedLabel = new JLabel("Lock account(True/False)");
// finish components(center panel)
statusArea = new JTextArea(25, 25);
statusArea.setEditable(false);
centerPanel.add(statusArea);
// add this to panel
isLockedCheckBox = new JCheckBox();
// add this to panel
// scrollers and Jlists
// ***********************************************************************
depositAmount = new JList(intList);
JScrollPane scroller1 = new JScrollPane(depositAmount);
scroller1
.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scroller1
.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
depositAmount.setVisibleRowCount(1);
depositAmount.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
withdrawAmount = new JList(intList);
JScrollPane scroller2 = new JScrollPane(depositAmount);
scroller2
.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scroller2
.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
depositAmount.setVisibleRowCount(1);
depositAmount.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
// ***********************************************************************
depositButton = new JButton("Deposit Amount.");
withdrawButton = new JButton("Withdraw Amount");
saveAccountButton = new JButton("Save your Account");
rightPanel.add(depositAmount);
rightPanel.add(depositButton);
frame.setSize(425, 650);
frame.setVisible(true);
}
private void serializeAccount() {
try {
ObjectOutputStream objectStream1 = new ObjectOutputStream(
new FileOutputStream("bankAccounts.txt"));
objectStream1.writeObject(account);
objectStream1.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
银行账户类：
package GUIs;
import java.io.Serializable;
public class BankAccount implements Serializable {
private static final long serialVersionUID = -5341449653011848470L;
int balance = 0;
int userWallet = 0;
String owner = "Foo Bar";
String status = "Account Owner: " + owner + "\nAccount balance: $"
+ balance + "\nOwner Wallet Balance: $" + userWallet;
boolean isLocked = false;
public int withdraw(int amount) {
balance -= amount;
userWallet += amount;
return userWallet;
}
public int deposit(int amount) {
balance += amount;
userWallet -= amount;
return balance;
}
public int depositCashIntoWallet(int amount) {
userWallet += amount;
return userWallet;
}
}