Question

我有这个例外我不明白为什么会被抛出或者我应该如何处理它。

        try{
            File file = chooser.getSelectedFile();
            ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
            oos.writeObject(frame);
            oos.writeObject(list);
            oos.close();
        }catch (IOException e){
            JOptionPane.showMessageDialog(null, e);
        }

我相信在读取oos.writeObject(frame)时会抛出异常。在这里，我试图将JFrame对象保存为二进制。以前我能够使用XMLEncoder类似地将同一个对象写入XML。

 import java.awt.*;
 import java.awt.event.*;
 import java.beans.*;
 import java.io.*;
 import java.util.ArrayList;

 import javax.swing.*;


 @SuppressWarnings("serial")
 public class SaveFrame implements Serializable{
public static JFileChooser chooser;
public JFrame frame;
public JTextArea textArea;
public ArrayList<String> list = new ArrayList<String>();
public static void main(String[] args){
    chooser = new JFileChooser();
    chooser.setCurrentDirectory(new File("."));      
    SaveFrame test = new SaveFrame();
    test.initialize();
}

public void initialize(){

    frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(800, 300);
    frame.getContentPane().setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));

    JButton loadXML = new JButton("LoadXML");
    frame.getContentPane().add(loadXML);
    loadXML.addActionListener(EventHandler.create(ActionListener.class, this, "loadXML"));

    JButton saveXML = new JButton("SaveXML");
    frame.getContentPane().add(saveXML);
    saveXML.addActionListener(EventHandler.create(ActionListener.class, this, "saveXML"));

    JButton loadBinary = new JButton("LoadBinary");
    frame.getContentPane().add(loadBinary);
    loadBinary.addActionListener(EventHandler.create(ActionListener.class, this, "loadBinary"));

    JButton saveBinary = new JButton("SaveBinary");
    frame.getContentPane().add(saveBinary);
    saveBinary.addActionListener(EventHandler.create(ActionListener.class, this, "saveBinary"));

    JButton storeData = new JButton("StoreData");
    frame.getContentPane().add(storeData);
    storeData.addActionListener(EventHandler.create(ActionListener.class, this, "storeData"));

    JButton printData = new JButton("PrintData");
    frame.getContentPane().add(printData);

    textArea = new JTextArea(30,30);
    frame.getContentPane().add(textArea);
    printData.addActionListener(EventHandler.create(ActionListener.class, this, "printData"));


    frame.setVisible(true);
}

public void loadXML(){
    int r = chooser.showOpenDialog(null);

    if(r == JFileChooser.APPROVE_OPTION){
        try{
            File file = chooser.getSelectedFile();
            XMLDecoder decoder = new XMLDecoder(new FileInputStream(file));
            decoder.readObject();
            decoder.close();
        }
        catch (IOException e){
            JOptionPane.showMessageDialog(null, e);
        }
    }
}

public void saveXML(){
    if (chooser.showSaveDialog(null) == JFileChooser.APPROVE_OPTION){
        try{
            File file = chooser.getSelectedFile();
            XMLEncoder encoder = new XMLEncoder(new FileOutputStream(file));
            encoder.writeObject(frame);
            encoder.writeObject(list);
            encoder.close();
        }
        catch (IOException e){
            JOptionPane.showMessageDialog(null, e);
        }
    }
}
public void storeData(){
    list.add(textArea.getText());
}
public void printData(){
    for(String s : list){
        textArea.append(s + " ");
    }
}
public void loadBinary() throws ClassNotFoundException{
    int r = chooser.showOpenDialog(null);

    if(r == JFileChooser.APPROVE_OPTION){
        try{
            File file = chooser.getSelectedFile();
            ObjectInputStream ois = new ObjectInputStream(new FileInputStream(file));
            ois.readObject();
            ois.close();
        }
        catch (IOException e){
            JOptionPane.showMessageDialog(null, e);
        }
    }
}
public void saveBinary(){
    if (chooser.showSaveDialog(null) == JFileChooser.APPROVE_OPTION){
        try{
            File file = chooser.getSelectedFile();
            ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
            oos.writeObject(frame);
            oos.writeObject(list);
            oos.close();
        }
        catch (IOException e){
            JOptionPane.showMessageDialog(null, e);
             }
          }
      } 
 }

当我保存到XML而不是二进制文件格式时，我不明白为什么它可行。我从ObjectOutputStream的documentation读取的所有内容及其示例都会让我相信这应该像XMLEncoder那样工作。我会为你打印出我的堆栈，但这是一个gui，我不知道如何在控制台中启用它。

Answer 1

根据你指出的documentation，

只有支持java.io.Serializable接口的对象才可以写入溪流。

并根据Java Doc of java.bean.EventHandler，它没有实现Serializable

Answer 2

我不知道你可能读过的东西会让你期待那些。

你特别关联的ObjectOutputStream Javadoc

只有支持java.io.Serializable接口的对象才能写入流。

它需要传递给它的对象以及通过非静态非瞬态引用从中可以访问的所有对象来实现Serializable。

XMLEncoder没有约束。

java.io.NotSerializableException：java.beans.EventHandler

2 个答案: