java - 从 MySQL 更新 GUI 中的 JTable

Question

我创建了一个连接到数据库的 GUI，在 JTable 中显示数据库信息。显示在JFrame中但是，当使用“添加数据”按钮时，我收到一条消息:数据已添加到 MySQL，但表没有更新？之后，下一步是更新/删除条目并将其显示在表中。

我对 Java 中的 GUI 比较陌生，只是想知道我是否缺少一个方法，就像我认为的 populateTable(); 一样。函数应该从我的 populateTable(); 自动执行此操作方法。

这就是我迄今为止写的所有内容

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;
import javax.swing.table.TableColumnModel;
import net.proteanit.sql.DbUtils;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JComboBox;
import javax.swing.JTextPane;

public class GUI3 extends JFrame {

    private static final long serialVersionUID = 1L;

    // DB Code
    DBHelper dbhelper = new DBHelper();
    Connection con = dbhelper.open();
    Statement st;
    ResultSet rs;

    DefaultTableModel model = new DefaultTableModel();

    private JPanel contentPane;
    private JTable table;
    private JTextField userText;
    private JTextField ageText;
    private JTextField surText;
    private JTextField genreText;
    private JTextField hairText;
    private JTextField genderText;
    private JTextField firstText;
    private GUI3 frame;
    private final Action action = new SwingAction();

    /**
     * Launch the application.
     */
    public void main() {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    frame = new GUI3();
                    frame.setVisible(true);

                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });                 
    }

    private void getUsersDataFromDB() {
        try {
            st = con.createStatement();
            String searchQuery = "SELECT * FROM user";
            rs = st.executeQuery(searchQuery);              
        } catch (Exception ex) {
            System.out.println(ex.getMessage());
            JOptionPane.showMessageDialog(null, (ex.getMessage()));
        }
    }

    private void populateTable() {
        getUsersDataFromDB();
        table.setModel(DbUtils.resultSetToTableModel(rs));
        JTableHeader th = table.getTableHeader();
        TableColumnModel tcm = th.getColumnModel();
        tcm.getColumn(0).setHeaderValue("User id");
        tcm.getColumn(1).setHeaderValue("Genre");
        tcm.getColumn(2).setHeaderValue("Hair Length");
        tcm.getColumn(3).setHeaderValue("Name");
        tcm.getColumn(4).setHeaderValue("Surname");
        tcm.getColumn(5).setHeaderValue("Age");
        tcm.getColumn(6).setHeaderValue("Gender");
        th.repaint();
    }

    /**
     * Create the frame.
     */

    public GUI3() {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 600, 426);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);

        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setBounds(17, 5, 548, 167);

        userText = new JTextField();
        userText.setBounds(17, 180, 70, 20);
        userText.setColumns(10);

        ageText = new JTextField();
        ageText.setBounds(415, 180, 75, 20);
        ageText.setColumns(10);

        surText = new JTextField();
        surText.setBounds(335, 180, 75, 20);
        surText.setColumns(10);

        genreText = new JTextField();
        genreText.setBounds(95, 180, 75, 20);
        genreText.setColumns(10);

        JButton addButton = new JButton("Add");
        addButton.setBounds(85, 225, 100, 25);
        addButton.addActionListener(new ActionListener()
        {
              @Override
                public void actionPerformed(ActionEvent e) {
                 String searchQuery = "INSERT INTO `user`(`user_id`, `genre_id`, `hair_length`, "+ "`user_fname`,`user_lname`,`user_age`,`user_gender`) " + "VALUES (?, ?, ?, ?, ?, ?, ?)";
                    try (PreparedStatement insert = con.prepareStatement(searchQuery)) {
                        insert.setString(1, userText.getText());
                        insert.setString(2, genreText.getText());
                        insert.setString(3, hairText.getText());
                        insert.setString(4, firstText.getText());
                        insert.setString(5, surText.getText());
                        insert.setString(6, ageText.getText());
                        insert.setString(7, genderText.getText());
                        JOptionPane.showMessageDialog(null, "Data Added To MySQL");
                    }catch(Exception ex){
                        ex.printStackTrace();
                    }
                    populateTable();
                }
            });



        // Update Button Functionality
        JButton updateButton = new JButton("Update");
        updateButton.setBounds(185, 225, 100, 25);
        updateButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
            String searchQuery = "UPDATE user (user_id, genre_id, hair_length, " + "user_fname, user_lname, user_age, user_gender) " + "VALUES (?, ?, ?, ?, ?, ?, ?)";  

                try (PreparedStatement insert = con.prepareStatement(searchQuery)) 
                {
                    insert.setString(1, userText.getText());
                    insert.setString(2, genreText.getText());
                    insert.setString(3, hairText.getText());
                    insert.setString(4, firstText.getText());
                    insert.setString(5, surText.getText());
                    insert.setString(6, ageText.getText());
                    insert.setString(7, genderText.getText());
                    JOptionPane.showMessageDialog(null, "Database Updated");
                }
                catch(Exception ex)
                {
                    ex.printStackTrace();
                }
                populateTable();
            }
        });


        // Delete Button Functionality
        JButton deleteButton = new JButton("Delete");
        deleteButton.setBounds(285, 225, 100, 25);
        deleteButton.addActionListener(new ActionListener() 
        {
            public void actionPerformed(ActionEvent e) 
            {
                 String searchQuery = "DELETE FROM USER WHERE (user_id, genre_id, hair_length, " + "user_fname, user_lname, user_age, user_gender) " + "VALUES (?, ?, ?, ?, ?, ?, ?)";  

                    try (PreparedStatement insert = con.prepareStatement(searchQuery)) {
                        insert.setString(1, userText.getText());
                        insert.setString(2, genreText.getText());
                        insert.setString(3, hairText.getText());
                        insert.setString(4, firstText.getText());
                        insert.setString(5, surText.getText());
                        insert.setString(6, ageText.getText());
                        insert.setString(7, genderText.getText());
                        JOptionPane.showMessageDialog(null, "Database Updated");
                    }catch(Exception ex){
                        ex.printStackTrace();
                    }
            }
        });

        hairText = new JTextField();
        hairText.setBounds(175, 180, 75, 20);
        hairText.setColumns(10);

        genderText = new JTextField();
        genderText.setBounds(495, 180, 70, 20);
        genderText.setColumns(10);

        firstText = new JTextField();
        firstText.setBounds(255, 180, 75, 20);
        firstText.setColumns(10);

        table = new JTable();
        populateTable();


        scrollPane.setViewportView(table);
        contentPane.setLayout(null);
        contentPane.add(firstText);
        contentPane.add(scrollPane);
        contentPane.add(userText);
        contentPane.add(genreText);
        contentPane.add(hairText);
        contentPane.add(surText);
        contentPane.add(ageText);
        contentPane.add(genderText);
        contentPane.add(addButton);
        contentPane.add(updateButton);
        contentPane.add(deleteButton);

        JComboBox comboBox = new JComboBox();
        comboBox.setBounds(35, 285, 75, 20);
        contentPane.add(comboBox);

        JComboBox comboBox_1 = new JComboBox();
        comboBox_1.setBounds(35, 310, 75, 20);
        contentPane.add(comboBox_1);

        JComboBox comboBox_2 = new JComboBox();
        comboBox_2.setBounds(35, 335, 75, 20);
        contentPane.add(comboBox_2);

        JTextPane textPane = new JTextPane();
        textPane.setBounds(285, 285, 270, 75);
        contentPane.add(textPane);

    }

}

Answer 1

您需要在更新、删除或添加后刷新表格，首先清除表格，然后在显示消息对话框成功添加/更新/删除或其他内容之后立即再次填充表格

JOptionPane.showMessageDialog(null, "Database Updated");
model.setRowCount(0);//clear table data
populateTable();//method you use to populate your table`