从 ResultSet 填充 JTable 的最简单代码 [英] Most simple code to populate JTable from ResultSet

问题描述

我用谷歌搜索了一整天，但没有运气.我在按下 OK 按钮后调用 getnPrintAllData() 方法.所以代码是:

I googled the whole day and no luck. I call getnPrintAllData() method after pressing OK button. So the code is:

public class DatabaseSQLiteConnection {
    Connection conn = null;
    PreparedStatement statement = null;
    ResultSet res = null;

    public DatabaseSQLiteConnection(){
        try{
            Class.forName("org.sqlite.JDBC");
            conn = DriverManager.getConnection("jdbc:sqlite:test.sqlite");
            statement = conn.prepareStatement("SELECT * from product_info;");
        }
        catch(Exception e){
            e.printStackTrace();
        }
    }   

    public void getnPrintAllData(){
        String name, supplier, id;
        DefaultTableModel dtm = new DefaultTableModel();
        Window gui = new Window(); //My JPanel class        
        try{
            res = statement.executeQuery();
            testResultSet(res);
            ResultSetMetaData meta = res.getMetaData();
            int numberOfColumns = meta.getColumnCount();
            while (res.next())
            {
                Object [] rowData = new Object[numberOfColumns];
                for (int i = 0; i < rowData.length; ++i)
                {
                    rowData[i] = res.getObject(i+1);
                }
                dtm.addRow(rowData);
            }
            gui.jTable1.setModel(dtm);
            dtm.fireTableDataChanged();
            //////////////////////////

        }
        catch(Exception e){
            System.err.println(e);
            e.printStackTrace();
        }
        finally{
            try{
                res.close();
                statement.close();
                conn.close();
            }
            catch(Exception e){
                e.printStackTrace();
            }
        }
    }    

    public void testResultSet(ResultSet res){
        try{
            while(res.next()){
                System.out.println("Product ID: "+ res.getInt("product_id"));
                System.out.println("Product name: "+ res.getString("product_name"));
                System.out.println("Supplier: "+ res.getString("supplier"));
            }        
        }
        catch(Exception e){
            e.printStackTrace();
        }
    }
}

我的 testResultSet() 方法工作正常.现在，如何更改我的代码以使其正常工作，或者从 ResultSet 生成 DefaultTableModel 的最简单代码是什么?提前致谢.

My testResultSet() method is working properly. Now, how to change my code so that it works, or what is the most simple code to make DefaultTableModel from ResultSet ? Thanks in advance.

我收到java.lang.IllegalStateException:SQLite JDBC:内部状态不一致错误.

推荐答案

我认为从 ResultSet 的实例构建模型的最简单方法可能如下所示.

I think the simplest way to build a model from an instance of ResultSet, could be as follows.

public static void main(String[] args) throws Exception {
    // The Connection is obtained

    ResultSet rs = stmt.executeQuery("select * from product_info");

    // It creates and displays the table
    JTable table = new JTable(buildTableModel(rs));

    // Closes the Connection

    JOptionPane.showMessageDialog(null, new JScrollPane(table));

}

方法buildTableModel:

public static DefaultTableModel buildTableModel(ResultSet rs)
        throws SQLException {

    ResultSetMetaData metaData = rs.getMetaData();

    // names of columns
    Vector<String> columnNames = new Vector<String>();
    int columnCount = metaData.getColumnCount();
    for (int column = 1; column <= columnCount; column++) {
        columnNames.add(metaData.getColumnName(column));
    }

    // data of the table
    Vector<Vector<Object>> data = new Vector<Vector<Object>>();
    while (rs.next()) {
        Vector<Object> vector = new Vector<Object>();
        for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
            vector.add(rs.getObject(columnIndex));
        }
        data.add(vector);
    }

    return new DefaultTableModel(data, columnNames);

}

<小时>

更新

您喜欢使用javax.swing.SwingWorker?你喜欢使用try-with-resources 声明?

Do you like to use javax.swing.SwingWorker? Do you like to use the try-with-resources statement?

public class GUI extends JFrame {

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new GUI().setVisible(true);
            }
        });
    }

    private final JButton button;
    private final JTable table;
    private final DefaultTableModel tableModel = new DefaultTableModel();

    public GUI() throws HeadlessException {

        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

        table = new JTable(tableModel);
        add(new JScrollPane(table), BorderLayout.CENTER);

        button = new JButton("Load Data");
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                new SwingWorker<Void, Void>() {
                    @Override
                    protected Void doInBackground() throws Exception {
                        loadData();
                        return null;
                    }
                }.execute();
            }
        });
        add(button, BorderLayout.PAGE_START);

        setSize(640, 480);
    }

    private void loadData() {
        LOG.info("START loadData method");

        button.setEnabled(false);

        try (Connection conn = DriverManager.getConnection(url, usr, pwd);
                Statement stmt = conn.createStatement()) {

            ResultSet rs = stmt.executeQuery("select * from customer");
            ResultSetMetaData metaData = rs.getMetaData();

            // Names of columns
            Vector<String> columnNames = new Vector<String>();
            int columnCount = metaData.getColumnCount();
            for (int i = 1; i <= columnCount; i++) {
                columnNames.add(metaData.getColumnName(i));
            }

            // Data of the table
            Vector<Vector<Object>> data = new Vector<Vector<Object>>();
            while (rs.next()) {
                Vector<Object> vector = new Vector<Object>();
                for (int i = 1; i <= columnCount; i++) {
                    vector.add(rs.getObject(i));
                }
                data.add(vector);
            }

            tableModel.setDataVector(data, columnNames);
        } catch (Exception e) {
            LOG.log(Level.SEVERE, "Exception in Load Data", e);
        }
        button.setEnabled(true);

        LOG.info("END loadData method");
    }

}

这篇关于从 ResultSet 填充 JTable 的最简单代码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！