Java GUI写入文件不起作用

Question

i am trying to implement GUI features to my java coding which i am trying out for the first time. But i tried a "Create Player Feature" in my code but it is not writing to file can someone help? thanks

private class createListener implements ActionListener{
    public void actionPerformed(ActionEvent event){

            JFrame frame = new JFrame("Create Player");
            JPanel panel = new JPanel();
            JPanel mainpanel = new JPanel();
            JButton create;
            JLabel welcome = new JLabel("Create Player");
            JLabel name = new JLabel("Enter Player Name");
            nameP = new JTextField();
            JLabel pass = new JLabel("Enter Player Password");
            password = new JTextField();
            JLabel chips = new JLabel("Enter Player Chips");
            chipsP = new JTextField();
            buttonCreate = new JButton("Create Player");

            setSize(400,350);
            setLocation(500,280);
            panel.setLayout(new GridLayout(0,1,10,10));

            panel.add(name);
            panel.add(nameP);
            panel.add(pass);
            panel.add(password);
            panel.add(chips);
            panel.add(chipsP);
            panel.add(buttonCreate);
            mainpanel.add(panel);

            getContentPane().removeAll();
            getContentPane().add(mainpanel);
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            setVisible(true);
            buttonCreate.addActionListener(new createListener());
        }

    }
    private class playerListener implements ActionListener{
    public void actionPerformed(ActionEvent event){
        String username = nameP.getText();
        String userpass = password.getText();
        String hasheduserP = Utility.getHash(userpass);
        String userchip = chipsP.getText();
        String userContent = username + "|" + hasheduserP + "|" + userchip;

        File file = new File("players.dat");
        try{
            //adding of user details
            PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("players.dat", true)));
            out.println(userContent);
            out.close();
            JOptionPane.showMessageDialog(null,"User Created");
        } catch (IOException ex){
            System.out.println("Error Writing to File");
        }



    }
}

Answer 1

The file related part of your code works without any problem.

Hint: Improve it like this:

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class SOPlayground {

    public static void main(String[] args) throws Exception {
        String userContent = "foo";

        try {
            try (PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("/tmp/players.dat", true)))) {
                out.println(userContent);
            }
        } catch (IOException ex) {
            System.err.println("Error Writing to File: " + ex.getMessage());
        }
    }
}

The content of /tmp/players.dat now is

foo