java - java中的序列化，在事件中重新膨胀对象？

Question

我正在尝试更多地了解java。该程序试图理解事件和序列化。我试图做的是在用户关闭 JFrame 时展平一个对象，并在程序启动时重新充气它。我知道我可以创建序列化文件，但让它再次生效不起作用。任何在正确方向上的帮助都会很棒。先感谢您。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import javax.swing.Timer;
import java.io.*;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class tempusFugit extends JFrame implements ActionListener, Serializable, WindowListener
{
String fileN = "tf.txt"; 
public int ToL = 0;
String outT = Integer.toString(ToL);
    JLabel jl = new JLabel(outT);

FileOutputStream fos = null;
ObjectOutputStream out = null;

public tempusFugit()

{
    Timer timer = new Timer(1000, this);

    setBounds(250, 250, 250, 190);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setLayout(new FlowLayout(FlowLayout.LEFT) );
    setVisible(true);
    add(jl);
    timer.start();
}

public void actionPerformed(ActionEvent e)
{
    ++ToL;
    outT = Integer.toString(ToL);
    jl.setText(outT);
    validate();
    repaint();
}
public static void main(String[] args)
{
    tempusFugit tf = new tempusFugit();
    tf.addWindowListener( tf );

}
public void windowDeactivated(WindowEvent e)
{
}
public void windowActivated(WindowEvent e)
{   
}
public void windowDeiconified(WindowEvent e)
{
}
public void windowIconified(WindowEvent e)
{
}
public void windowClosed(WindowEvent e)
{
}
public void windowClosing(WindowEvent e)
{
    try
    {
        fos = new FileOutputStream(fileN);
        out = new ObjectOutputStream(fos);
        out.writeObject(this);
        out.close();

    }
    catch(IOException ex)
    {
}
}
public void windowOpened(WindowEvent e)
{
try
    {
        tempusFugit tf = new tempusFugit();
        FileInputStream fis = new FileInputStream(fileN);
        ObjectInputStream in = new ObjectInputStream(fis);
        tf = (tempusFugit)in.readObject();
        this.ToL = tf.ToL;
    }
    catch(IOException ex)
    {
    }
    catch(ClassNotFoundException ce)
    {
    }

}

}

我假设我试图在错误的时间重新创建对象。即使对象被正确序列化，我也无法使用 windowOpened 函数再次访问它。我需要尝试使用吗

private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException;

不知何故？

我最终得到的是一个错误，说我正在尝试访问一个 Final 对象(我假设我的这个)。我觉得很奇怪，我不能用另一个类似的对象重新填充我当前的“this”。

我离基地很远吗？

再次感谢您的时间。

Answer 1

请注意，有比序列化框架更简单的方法来做到这一点，并且序列化比框架本身更好。

见 What is the best practice for setting JFrame locations in Java?例如存储帧的位置和大小。调整它来存储计数将是微不足道的。

但这是基于您的代码的尝试。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import javax.swing.Timer;
import java.io.*;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class tempusFugit extends JFrame implements ActionListener, Serializable, WindowListener
{
    String fileN = "tf.txt";
    public int ToL = 0;
    JLabel jl = new JLabel("" + ToL);

    public tempusFugit()
    {
        Timer timer = new Timer(1000, this);

        setBounds(250, 250, 250, 190);
        setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
        setLayout(new FlowLayout(FlowLayout.LEFT) );
        setVisible(true);
        add(jl);
        timer.start();
    }

    public void actionPerformed(ActionEvent e)
    {
        ++ToL;
        jl.setText("" + ToL);
        validate();
        repaint();
    }

    public static void main(String[] args)
    {
        tempusFugit tf = new tempusFugit();
        tf.addWindowListener( tf );
    }

    public void windowDeactivated(WindowEvent e){}
    public void windowActivated(WindowEvent e){}
    public void windowDeiconified(WindowEvent e){}
    public void windowIconified(WindowEvent e){}
    public void windowClosed(WindowEvent e){}

    public void windowClosing(WindowEvent e)
    {
        try
        {
            FileOutputStream fos = new FileOutputStream(fileN);
            ObjectOutputStream out = new ObjectOutputStream(fos);
            out.writeObject(this);
            out.flush();
            out.close();
            setVisible(false);
            System.exit(0);
        }
        catch(IOException ex)
        {
            JOptionPane.showMessageDialog(null, ex);
            System.exit(1);
        }
    }

    public void windowOpened(WindowEvent e)
    {
        try
        {
            tempusFugit tf;// = new tempusFugit();
            FileInputStream fis = new FileInputStream(fileN);
            ObjectInputStream in = new ObjectInputStream(fis);
            tf = (tempusFugit)in.readObject();
            this.ToL = tf.ToL;
            //tf.setVisible(false);
        }
        catch(IOException ex)
        {
            ex.printStackTrace();
        }
        catch(ClassNotFoundException ce)
        {
            ce.printStackTrace();
        }
    }
}