java - 在 jtable 中显示查询

Question

你好，我正在为我的 Java 类做一个项目，简单来说，我必须做一个让你手动查询的程序，就像我放一个文本框示例“select * from table”并显示结果，第二问题是如果删除、更新或插入程序应该自动执行选择语句以显示结果。

public class InfoCd extends JFrame {

    private JPanel contentPane;
    private JTable table;
    private JTextField textQuery;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    InfoCd frame = new InfoCd();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
Connection conn=null;

    /**
     * Create the frame.
     */
    public InfoCd() {

        conn=sqliteConnection.dbConnector();

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 753, 477);
        contentPane = new JPanel();
        contentPane.setBackground(SystemColor.activeCaption);
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JButton btnHacerConsulta = new JButton("Hacer Consulta");
        btnHacerConsulta.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {
                    String query="'?'";
                    PreparedStatement pst=conn.prepareStatement(query);
                    pst.setString(1, textQuery.getText());
                    ResultSet rs=pst.executeQuery();
                    table.setModel(DbUtils.resultSetToTableModel(rs));
                } catch (Exception e2) {
                    e2.printStackTrace();
                }

            }
        });
        btnHacerConsulta.setBounds(112, 388, 169, 39);
        contentPane.add(btnHacerConsulta);

        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setBounds(0, 0, 737, 367);
        contentPane.add(scrollPane);

        table = new JTable();
        scrollPane.setViewportView(table);

        textQuery = new JTextField();
        textQuery.setFont(new Font("Arial", Font.BOLD | Font.ITALIC, 11));
        textQuery.setHorizontalAlignment(SwingConstants.CENTER);
        textQuery.setText("Escribir Consulta Aqui");
        textQuery.setToolTipText("");
        textQuery.setBounds(422, 388, 270, 39);
        contentPane.add(textQuery);
        textQuery.setColumns(10);
    }
}

Answer 1

通常 SQL 看起来像这样:

String query = "Select * from TableName";
Statement statement = connection.createStatement();
ResultSet rs = statement.executeQuery(query);

因此，如果您想通过文本字段中的查询动态执行此操作，您只需执行以下操作:

String query = textField.getText();
Statement statement = connection.createStatement();
ResultSet rs = statement.executeQuery(query);

因此，由用户在文本字段中键入正确的 SQL 查询。

阅读 SQL Basics 上的教程获取更多信息。