文本文件被覆盖而不是保存时出现问题

Question

Book bookInfo = new Book(bookTitle, author, publisher, brandCallNumber, numberOfCopies);

然后将这个变量添加到arrayList，我在程序中调用WriteToFile（）方法。

AddBookDialog类的代码

public class AddBookDialog extends javax.swing.JDialog {

ArrayList<Book> books = new ArrayList<Book>();
/**
 * Creates new form AddBook
 */
public AddBookDialog(java.awt.Frame parent, boolean modal) {
    super(parent, modal);
    initComponents();
}

               

private void jButtonSaveToLibraryActionPerformed(java.awt.event.ActionEvent evt) {                                                     
    String bookTitle = jTextFieldTitle.getText();
    String author = jTextFieldAuthor.getText();
    String publisher = jTextFieldPublisher.getText();
    String brandCallNumber = jTextFieldBranchCallNumber.getText();
    int numberOfCopies = Integer.parseInt(jTextFieldCopies.getText());
    
    Book bookInfo = new Book(bookTitle, author, publisher, brandCallNumber, numberOfCopies);
    
    books.add(bookInfo);
    
    WriteToFile();
    this.setVisible(false);
}                                                    

private void WriteToFile()
{
    WriteFile wf = new WriteFile("BookDetails.txt");
    
    for(int i = 0; i < books.size(); i++)
    {
     Book b = books.get(i);
     String bookDetails = b.getBookTitle() + " : " + b.getAuthorName() + " : " + b.getPublisherName() + " : " + b.getBranchCallNumber() + " : " + b.getNumberOfCopies();
     
     wf.write(bookDetails);
    }
    wf.close();
}

WriteFile类的代码

public class WriteFile{
private FileOutputStream filename;

public WriteFile(String inputfilename)
{
    try
    {
        filename = new FileOutputStream(inputfilename,false);
    }
    catch (IOException e) {}
 }

 public void write(String item)
 {
    PrintStream output = new PrintStream(filename);
    output.println(item);
 }

 public void close()
 {
    try
    {
        filename.close();
    }
    catch (IOException e) {
      e.printStackTrace();
}
 }
}

相反，当我尝试向该文件写入另一本书时，它反而覆盖了第一行

哈姆雷特：威廉莎士比亚：企鹅：FIC Shak：23

//《哈利·波特》的书中详细内容已被改写