BufferedWriter is not writing a new line in a file for a String having “\n” added to it

问题

I was trying some stuff in Swing (Java), but getting very strange results.

I am getting a String from JTextArea.getText() method and adding "\n" to it. This resultant string I am writing into a file, using BufferedWriter which is chaining through FileOutputStream to a file. But the new line character "\n" is not creating new line in the .txt file.

How can I fix this issue?

My Code is here:

package quizCardGame;

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

public class QuizCardBuilder extends JFrame {
private static final long serialVersionUID = 1L;

private JTextArea question;
private JTextArea answer;
private Font font;
private ArrayList<QuizCard> deck;
private int countOfDeck;
private JLabel countLable;

public QuizCardBuilder() {
    super();
    deck = new ArrayList<QuizCard>();
    buildGUI();

}

public static void main(String[] args) {
    QuizCardBuilder app = new QuizCardBuilder();
}

public void buildGUI() {
    font = new Font(Font.SERIF, Font.BOLD, 12);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel panel = new JPanel();
    this.getContentPane().add(BorderLayout.CENTER, panel);

    JPanel stats = new JPanel();
    countLable = new JLabel("Count: " + countOfDeck);
    stats.add(countLable);

    this.getContentPane().add(BorderLayout.SOUTH, stats);

    JLabel qLable = new JLabel("Question");
    panel.add(qLable);

    question = new JTextArea(5, 30);
    question.setLineWrap(true);
    question.setWrapStyleWord(true);
    question.setFont(font);

    JScrollPane qScroller = new JScrollPane(question);
    qScroller
            .setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    qScroller
            .setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);

    panel.add(qScroller);

    JLabel aLable = new JLabel("Answer");
    panel.add(aLable);

    answer = new JTextArea(5, 30);
    answer.setLineWrap(true);
    answer.setWrapStyleWord(true);
    answer.setFont(font);

    JScrollPane aScroller = new JScrollPane(answer);
    aScroller
            .setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    aScroller
            .setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);

    panel.add(aScroller);

    JButton nextButton = new JButton("Next");
    nextButton.addActionListener(new NextCardListener());

    panel.add(nextButton);

    JMenuBar menuBar = new JMenuBar();
    JMenu fileMenu = new JMenu("File");
    JMenuItem newMenuItem = new JMenuItem("New");
    JMenuItem saveMenuItem = new JMenuItem("Save");

    fileMenu.add(newMenuItem);
    fileMenu.add(saveMenuItem);
    menuBar.add(fileMenu);
    this.setJMenuBar(menuBar);

    newMenuItem.addActionListener(new NewMenuListener());
    saveMenuItem.addActionListener(new SaveMenuListener());

    this.setSize(350, 350);
    this.setVisible(true);
}

public class SaveMenuListener implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e) {
        deck.add(new QuizCard(question.getText(), answer.getText()));

        JFileChooser fileSave = new JFileChooser();
        fileSave.showSaveDialog(null);
        saveFile(fileSave.getSelectedFile());
    }

}

public void saveFile(File file) {

    try {
        BufferedWriter bw = new BufferedWriter(new FileWriter(file));
        for (QuizCard card : deck) {
            bw.write(card.getQuestion() + "/");
            bw.write(card.getAnswer() + "\n");
        }

        bw.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

public class NewMenuListener implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e) {
        deck.clear();
        countOfDeck = deck.size();
        countLable.setText("Count: " + countOfDeck);
        clearText();
    }

}

public class NextCardListener implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e) {
        deck.add(new QuizCard(question.getText(), answer.getText()));
        countOfDeck = deck.size();
        countLable.setText("Count: " + countOfDeck);
        clearText();
    }

}

private void clearText() {
    question.setText("");
    answer.setText("");
}

}

回答1:

Use instead BufferedWriter.newLine() which:

Writes a line separator. The line separator string is defined by the system property line.separator, and is not necessarily a single newline ('\n') character.

来源：https://stackoverflow.com/questions/28692596/bufferedwriter-is-not-writing-a-new-line-in-a-file-for-a-string-having-n-adde