java - 为什么这个程序会出现 ClassNotFound 异常？

Question

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已关闭 10 年前。

我需要这个简单的虚拟银行程序在每次启动时反序列化主帐户。我已经这样做了，但是运行此方法的 GUI 类继续给我一个 java.lang.ClassNotFoundException 。我不确定我的错误是什么或如何修复它，我应该做什么？我将在下面发布这两个类，因为我不确定在哪里可以找到错误。

BankGUI 类:

package GUIs;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridBagLayout;
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;

import virtualBank3.BankAccount;

@SuppressWarnings("serial")
public class BankGUI implements Serializable {

    BankAccount account;

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (Exception e) {
            e.printStackTrace();
        }
        BankGUI gui = new BankGUI();
        gui.deserializeAccount();
        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, 100, 150, 250, 500 };

        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(15, 22);
        statusArea.setEditable(false);
        // 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");

        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 (IOException e) {
            e.printStackTrace();
        }
    }

    private void deserializeAccount() {
        try {
            ObjectInputStream objectStream2 = new ObjectInputStream(
                    new FileInputStream("bankAccounts.txt"));
            account = (BankAccount) objectStream2.readObject();
            objectStream2.close();
            //test it
            System.out.println("It worked.");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

银行账户类:

package virtualBank3;

import java.io.Serializable;

public class BankAccount implements Serializable {

    private static final long serialVersionUID = -5341449653011848470L;

    int balance = 0;
    int userWallet = 0;
    String owner = "Hello, world";
    String accountStat = "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;
    }


}

错误如下:

java.lang.ClassNotFoundException: virtualBank3.Account
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Unknown Source)
    at java.io.ObjectInputStream.resolveClass(Unknown Source)
    at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
    at java.io.ObjectInputStream.readClassDesc(Unknown Source)
    at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
    at java.io.ObjectInputStream.readObject0(Unknown Source)
    at java.io.ObjectInputStream.readObject(Unknown Source)
    at GUIs.BankGUI.deserializeAccount(BankGUI.java:123)
    at GUIs.BankGUI.main(BankGUI.java:40)

Answer 1

这是一个命名问题 - 您有一个公共(public)类 virtualBank3.BankAccount，但序列化文件引用了一个virtualBank3.Account。序列化文件是你写的还是别人给你的？如果是前者，您重命名了一个类，但没有重新创建序列化文件。