Question

作为练习，我创建了一个Books列表作为LinkedList，并使用Comparator接口按作者或标题对它们进行排序。首先，我创建了一类书籍，并确保它将按照我想要的方式进行打印：

class Book {
    String title;
    String author;
    public Book(String t, String a){
        title = t;
        author = a;
    }
    public String toString(){
        return title + "\t" + author;
    }
}

接下来，我创建了一个使用Object Book的LinkedList：

LinkedList<Book> bookList = new LinkedList<>();

创建一个实现Comparator的类，根据title / author进行排序，并将它们显示在主框架内的JTextArea上。所有这一切都很好，但有一个明显的错误......我无法保存文件！

我尝试过一个实现Serializable的类，它将LinkedList作为参数，然后写一个.obj文件。当我加载它时，它失败了。它会创建文件，但我通常会收到NotSerializableException。我也尝试将文件保存为.ser，因为我被告知这样可以更容易保存它，但是加载失败也是如此。

有没有人知道使用BufferedReader序列化LinkedList的好方法？或者还有另一种方法吗？感谢您抽出时间阅读此问题，并感谢您提供的任何建议，意见或答案。谢谢，伙计们。

增加：这是整个代码：

import javax.swing.*;
import java.util.*;
import java.awt.event.*;
import java.awt.*;
import java.io.*;

public class Check {

    BookCompare bc = new BookCompare();
    LinkedList<Book> bookList = new LinkedList<>();
    JFrame frame;
    JPanel northPanel, centerPanel, southPanel;
    JButton addBook, saveBook, loadBook;
    JTextField authorField, titleField;
    JTextArea displayBook;

    public static void main(String[] args) {
        new Check().buildGui();
    }

    private void buildGui() {
        frame = new JFrame("Book List");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        northPanel = new JPanel();
        centerPanel = new JPanel();
        southPanel = new JPanel();

        addBook = new JButton("Add Book");
        addBook.addActionListener(new AddButton());
        saveBook = new JButton("Save List");
        saveBook.addActionListener(new SaveButton());
        loadBook = new JButton("Load List");
        loadBook.addActionListener(new LoadButton());

        JLabel authorL = new JLabel("Author:");
        authorField = new JTextField(10);
        JLabel titleL = new JLabel("Title:");
        titleField = new JTextField(10);

        displayBook = new JTextArea(20,40);
        displayBook.setEditable(false);
        JScrollPane scroll = new JScrollPane(displayBook);
        scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        scroll.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);

        northPanel.add(titleL);
        northPanel.add(titleField);
        northPanel.add(authorL);
        northPanel.add(authorField);
        centerPanel.add(scroll);
        southPanel.add(addBook);
        southPanel.add(saveBook);
        southPanel.add(loadBook);

        frame.getContentPane().add(BorderLayout.NORTH,northPanel);
        frame.getContentPane().add(BorderLayout.CENTER,centerPanel);
        frame.getContentPane().add(BorderLayout.SOUTH,southPanel);

        frame.setVisible(true);
        frame.setSize(500, 500);
        frame.setResizable(false);
        frame.setLocation(375, 50);
    }

    class AddButton implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            addToList();
            sortAndDisplay();
            readyNext();
        }
    }

    private void addToList() {
        String newTitle = titleField.getText();
        String newAuthor = authorField.getText();
        bookList.add(new Book(newTitle, newAuthor));
    }

    private void sortAndDisplay() {
        displayBook.setText(null);
        Collections.sort(bookList,bc);
        for(int i = 0; i < bookList.size(); i++){
            displayBook.append(bookList.get(i).toString());
        }
    }

    private void readyNext() {
        authorField.setText(null);
        titleField.setText(null);
        titleField.requestFocus();
    }

    class SaveButton implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            try {
                ObjectOutputStream oo = new ObjectOutputStream(new FileOutputStream("save.ser"));
                oo.writeObject(bookList);
                oo.close();
            } catch (IOException ioe){}
        }
    }

    class LoadButton implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            try {
                ObjectInputStream oi = new ObjectInputStream(new FileInputStream("save.ser"));
                Object booksIn = oi.readObject();
                Book inBook = (Book)booksIn;
                bookList.add(inBook);
                sortAndDisplay();
                oi.close();
            } catch (Exception exc){}
        }
    }

    class BookCompare implements Comparator<Book> {
        public int compare(Book one, Book two) {
            return one.title.compareTo(two.title);
        }
    }

    class Book implements Serializable{
        String title;
        String author;
        public Book(String t, String a) {
            title = t;
            author = a;
        }
        public String toString(){
            return title + "\t" + author + "\n";
        }
    }
}

Answer 1

按照这样的方式制作您的图书课程Serializable

class Book implements Serializable{
  String title;
  String author;
  public Book(String t, String a){
     title = t;
     author = a;
  }
  public String toString(){
     return title + "\t" + author;
  }
}

序列化接口没有方法或字段，只用于识别可序列化的语义。所以你不需要实现任何方法，只需声明就足够了。
根据java docs

实现java.io.Serializable接口的类启用了类的可序列化。未实现此接口的类将不会将其任何状态序列化或反序列化。可序列化类的所有子类型本身都是可序列化的。序列化接口没有方法或字段，仅用于标识可序列化的语义。

更新以解决当前问题
你已经错误地实现了反序列化过程。这是正确的实现。试试这个你会得到理想的结果。

class LoadButton implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        try {
            ObjectInputStream oi = new ObjectInputStream(new FileInputStream("save.ser"));
            Object booksIn = oi.readObject();
            bookList = (LinkedList<Book>)booksIn;
            sortAndDisplay();
            oi.close();
        } catch (Exception exc){}
    }
 }

序列化LinkedList <object> </object>的语法

1 个答案: