java - AWT-EventQueue-0“StackOverflowError

Question

下午，我对一些 JFrame 代码有疑问，当用户按下“新用户”时，此 JFrame 就会启动，每当他们这样做时，我都会得到:

Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at frontend.Registration.<init>(Registration.java:36)
at frontend.Registration.<init>(Registration.java:25)
at frontend.Registration.<init>(Registration.java:25)
at frontend.Registration.<init>(Registration.java:25)

使用此代码:

package frontend;

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.SQLException;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class Registration extends JFrame {

/**
 * 
 */
private static final long serialVersionUID = 1L;

private static boolean ranOnce = false;

private JPanel contentPane;
private Registration reg = new Registration();
private JTextField userTF;
private JTextField passTF;
private JTextField emailTF;

private LoginProcess lp = new LoginProcess();
private JLabel error;

/**
 * Create the frame.
 */
public Registration() {
    if (!ranOnce) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    ranOnce = true;
                    reg = new Registration();
                    reg.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setBounds(100, 100, 245, 195);
    setLocationRelativeTo(null);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);

    JLabel lblUsername = new JLabel("Username:");
    lblUsername.setBounds(10, 11, 75, 14);
    contentPane.add(lblUsername);

    JLabel lblPassword = new JLabel("Password:");
    lblPassword.setBounds(10, 36, 75, 14);
    contentPane.add(lblPassword);

    JLabel lblEmail = new JLabel("Email:");
    lblEmail.setBounds(10, 61, 75, 14);
    contentPane.add(lblEmail);

    userTF = new JTextField();
    userTF.setBounds(95, 8, 130, 20);
    contentPane.add(userTF);
    userTF.setColumns(10);

    passTF = new JTextField();
    passTF.setColumns(10);
    passTF.setBounds(95, 33, 130, 20);
    contentPane.add(passTF);

    emailTF = new JTextField();
    emailTF.setColumns(10);
    emailTF.setBounds(95, 58, 130, 20);
    contentPane.add(emailTF);

    error = new JLabel("Error: Username already in use");
    error.setBounds(10, 120, 215, 14);
    contentPane.add(error);

    JButton regBtn = new JButton("Register");
    regBtn.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
            try {
                if (lp.newUser(userTF.getText(), passTF.getText(), emailTF.getText())) {
                    reg.setVisible(false);
                    Main.mainFrame.setVisible(true);
                } else {
                    if (lp.duplicateAccount) {
                        error.setText("lol");
                    }
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    });
    regBtn.setBounds(10, 86, 215, 23);
    contentPane.add(regBtn);


}
}

我知道这个错误是由无限循环或其他原因引起的。但我有一个 boolean 值来阻止它无限运行。该代码大约 20 分钟前运行，自从创建代码以来我没有更改构造函数的第一部分。

有什么想法吗？谢谢..

Answer 1

您在private Registration reg = new Registration();行中创建一个新对象。

您应该在构造函数中创建此对象。