Java自动计算表格某一数字列的和

package com.han;

import java.awt.BorderLayout;
import java.awt.Container;
import java.util.Vector;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.DefaultTableModel;

/**
 * 自动计算表格某一数字列的和
 * @author HAN
 *
 */
public class TabelModelEvent_2 extends JFrame {

	/**
	 * 
	 */
	private static final long serialVersionUID = 7045416728019138021L;

	float sum = 0;

	public TabelModelEvent_2() {
		// TODO Auto-generated constructor stub
		final Container container = getContentPane();
		JScrollPane scrollPane = new JScrollPane();
		Vector tableNames = new Vector();
		tableNames.add("数字列");
		Vector> tableValues = new Vector>();
		for (int i = 0; i < 4; i++) {
			Vector vector = new Vector();
			vector.add(null);
			tableValues.add(vector);
		}
		final DefaultTableModel defaultTabelModel = new DefaultTableModel(
				tableValues, tableNames);
		JTable table = new JTable(defaultTabelModel);
		scrollPane.setViewportView(table);
		container.add(scrollPane, BorderLayout.CENTER);
		JPanel panel = new JPanel();
		JLabel label = new JLabel("数字列总和：");
		final JTextField textField = new JTextField(10);
		panel.add(label);
		panel.add(textField);
		container.add(panel, BorderLayout.SOUTH);

		defaultTabelModel.addTableModelListener(new TableModelListener() {

			@Override
			public void tableChanged(TableModelEvent e) {
				// TODO Auto-generated method stub
				if (e.getType() == TableModelEvent.UPDATE) {
					int row = e.getFirstRow();
					int column = e.getColumn();

					// keep that every cell value is float or null.
					try {
						Float.parseFloat((String) defaultTabelModel.getValueAt(
								row, column));
					} catch (NumberFormatException e1) {
						JOptionPane.showMessageDialog(container,
								"Your input object is not a float type");
						defaultTabelModel.setValueAt(null, row, column);
					} catch (NullPointerException e2) {
						// do nothing
					}

					for (int i = 0; i < 4; i++) {
						Object cellValue = defaultTabelModel.getValueAt(i, 0);
						if (cellValue != null) {

							float floatValue = Float
									.parseFloat((String) cellValue);
							sum += floatValue;

						}
					}
				}
				textField.setText(new Float(sum).toString());
				sum = 0;
			}

		});
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		TabelModelEvent_2 frame = new TabelModelEvent_2();
		frame.setTitle("自动计算表格某一数字列的和");
		frame.pack();
		frame.setVisible(true);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

}