通过jdbc添加数据成功后，表中所添加的数据的行没数据不显示

Question

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;

public class gui4{
    private String driver = "com.mysql.cj.jdbc.Driver";
    private String url = "jdbc:mysql://localhost:3306/amd";
    private String user = "root";
    private String password = "123456";
    public gui4() {
        JFrame jFrame = new JFrame("管理员端");
        jFrame.setSize(800, 100);
        jFrame.setLocation(600, 390);
        jFrame.setLayout(new FlowLayout());
        JLabel jLabel1 = new JLabel("账号");
        JLabel jLabel2 = new JLabel("密码");
        TextField textField1 = new TextField(20);
        String newid=textField1.getText();
        TextField textField2 = new TextField(20);
        String newpassword=textField2.getText();
        JButton jButton1 = new JButton("注册");
        jButton1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    Connection connection=DriverManager.getConnection(url,user,password);
                    String sql1 = "insert into teacher(id, password)values(?,?)";
                    PreparedStatement preparedStatement= connection.prepareStatement(sql1);
                    preparedStatement.setString(1,newid);
                    preparedStatement.setString(2,newpassword);
                    int R=preparedStatement.executeUpdate();
                    if (R!=0){
                        JOptionPane.showMessageDialog(null,"注册成功");
                    }
                    textField1.setText(" ");
                    textField2.setText(" ");
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
        });
        JButton jButton2 = new JButton("登录");
        jButton2.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                try {
                    Connection connection=DriverManager.getConnection(url,user,password);
                    String sql2="select * from teacher where id=? and password=?";
                    PreparedStatement preparedStatement=connection.prepareStatement(sql2);
                    preparedStatement.setString(1,newid);
                    preparedStatement.setString(2,newpassword);
                    ResultSet resultSet=preparedStatement.executeQuery();
                    if (resultSet.next()){
                        new cs();//打开页面2，
                        jFrame.dispose();;//关闭页面1
                    }
                    textField1.setText(" ");
                    textField2.setText(" ");
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
        });

        jFrame.add(jLabel1);
        jFrame.add(textField1);
        jFrame.add(jLabel2);
        jFrame.add(textField2);
        jFrame.add(jButton1);
        jFrame.add(jButton2);
        jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭屏
        jFrame.setVisible(true);
    }
}

我用新加的数据进行登录是可以登录成功的，数据应该是添加成功的
是字符集的问题吗

Answer 1

获取控件的账号密码应该放在listener事件里面
因为只有点击注册按钮触发事件之前，是没有输入账号密码，所以为空