JTable Calculating column sum

Question

I have a JTable which is being populated by a ResultSet. Is there any way to calculate the sum of a specific column and add it to the bottom row of the same table?

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);

}


    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));
}

If there is a column called qty is there a way to get the total at the bottom of the table?

Answer 1

Hope this helps

jTable1.setColumnSelectionAllowed(true);
jTable1.getColumnModel().getSelectionModel().setSelectionMode(javax.swing.ListSelectionModel.SINGLE_INTERVAL_SELECTION);



public void calculate() {
    calculate(jTable1, jTable1.getSelectedColumn(), jTable1.getSelectedRows());
}

public void calculate(JTable table, int column, int[] rows) {
    int result = 0;
    for (int row : rows) {
        result += Integer.valueOf(table.getValueAt(row, column).toString());
    }
    ((DefaultTableModel) table.getModel()).addRow(new Object[]{result});
}