絮叨JTable的学习

SWING DEMO 

不知道从什么时候开始，JDK包里已经看不到demo文件夹了，费了很大劲才从oracle.com上找到"JDK 7 Demos and Samples"，原来这部分已经单独提供下载，我奥特曼了。

废话少说，down下这个DEMO包并解压之，打开"demo\jfc\SwingSet2\SwingSet2.html"。

如果IE不支持applet，先确认环境变量设置了JDK的path，然后在command下进入"demo\jfc\SwingSet2"所在目录，运行"appletViewer SwingSet2.html"命令。

这个例子是SWING的DEMO，很有学习价值，里面对JTable有一个单独的介绍模块。

在"jfc\TableExample\src"中，也有几个Table的例子，其中TableExample3.java和TableExample4.java可以单独运行，其他的需要连接数据库才行。

 下面把TableExample3.java贴出来学习：

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/*

 * This source code is provided to illustrate the usage of a given feature

 * or technique and has been deliberately simplified. Additional steps

 * required for a production-quality application, such as security checks,

 * input validation and proper error handling, might not be present in

 * this sample code.

 */







import javax.swing.*;

import javax.swing.table.*;



import java.awt.event.WindowAdapter;

import java.awt.event.WindowEvent;

import java.awt.Dimension;

import java.util.logging.Level;

import java.util.logging.Logger;

import javax.swing.UIManager.LookAndFeelInfo;





/**

 * An example showing the JTable with a dataModel that is not derived

 * from a database. We add the optional TableSorter object to give the

 * JTable the ability to sort.

 *

 * @author Philip Milne

 */

public class TableExample3 {



    public TableExample3() {

        JFrame frame = new JFrame("Table");

        frame.addWindowListener(new WindowAdapter() {



            @Override

            public void windowClosing(WindowEvent e) {

                System.exit(0);

            }

        });



        // Take the dummy data from SwingSet.

        final String[] names = { "First Name", "Last Name", "Favorite Color",

            "Favorite Number", "Vegetarian" };

        final Object[][] data = {

            { "Mark", "Andrews", "Red", new Integer(2), Boolean.TRUE },

            { "Tom", "Ball", "Blue", new Integer(99), Boolean.FALSE },

            { "Alan", "Chung", "Green", new Integer(838), Boolean.FALSE },

            { "Jeff", "Dinkins", "Turquois", new Integer(8), Boolean.TRUE },

            { "Amy", "Fowler", "Yellow", new Integer(3), Boolean.FALSE },

            { "Brian", "Gerhold", "Green", new Integer(0), Boolean.FALSE },

            { "James", "Gosling", "Pink", new Integer(21), Boolean.FALSE },

            { "David", "Karlton", "Red", new Integer(1), Boolean.FALSE },

            { "Dave", "Kloba", "Yellow", new Integer(14), Boolean.FALSE },

            { "Peter", "Korn", "Purple", new Integer(12), Boolean.FALSE },

            { "Phil", "Milne", "Purple", new Integer(3), Boolean.FALSE },

            { "Dave", "Moore", "Green", new Integer(88), Boolean.FALSE },

            { "Hans", "Muller", "Maroon", new Integer(5), Boolean.FALSE },

            { "Rick", "Levenson", "Blue", new Integer(2), Boolean.FALSE },

            { "Tim", "Prinzing", "Blue", new Integer(22), Boolean.FALSE },

            { "Chester", "Rose", "Black", new Integer(0), Boolean.FALSE },

            { "Ray", "Ryan", "Gray", new Integer(77), Boolean.FALSE },

            { "Georges", "Saab", "Red", new Integer(4), Boolean.FALSE },

            { "Willie", "Walker", "Phthalo Blue", new Integer(4), Boolean.FALSE },

            { "Kathy", "Walrath", "Blue", new Integer(8), Boolean.FALSE },

            { "Arnaud", "Weber", "Green", new Integer(44), Boolean.FALSE }

        };



        // Create a model of the data.

        @SuppressWarnings("serial")

        TableModel dataModel = new AbstractTableModel() {

            // These methods always need to be implemented.



            public int getColumnCount() {

                return names.length;

            }



            public int getRowCount() {

                return data.length;

            }



            public Object getValueAt(int row, int col) {

                return data[row][col];

            }



            // The default implementations of these methods in

            // AbstractTableModel would work, but we can refine them.

            @Override

            public String getColumnName(int column) {

                return names[column];

            }



            @Override

            public Class getColumnClass(int col) {

                return getValueAt(0, col).getClass();

            }



            @Override

            public boolean isCellEditable(int row, int col) {

                return (col == 4);

            }



            @Override

            public void setValueAt(Object aValue, int row, int column) {

                data[row][column] = aValue;

            }

        };



        // Instead of making the table display the data as it would normally

        // with:

        // JTable tableView = new JTable(dataModel);

        // Add a sorter, by using the following three lines instead of the one

        // above.

        TableSorter sorter = new TableSorter(dataModel);

        JTable tableView = new JTable(sorter);

        sorter.addMouseListenerToHeaderInTable(tableView);



        JScrollPane scrollpane = new JScrollPane(tableView);



        scrollpane.setPreferredSize(new Dimension(700, 300));

        frame.getContentPane().add(scrollpane);

        frame.pack();

        frame.setVisible(true);

    }



    public static void main(String[] args) {

        // Trying to set Nimbus look and feel

        try {

            for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {

                if ("Nimbus".equals(info.getName())) {

                    UIManager.setLookAndFeel(info.getClassName());

                    break;

                }

            }

        } catch (Exception ex) {

            Logger.getLogger(TableExample3.class.getName()).log(Level.SEVERE,

                    "Failed to apply Nimbus look and feel", ex);

        }

        new TableExample3();

    }

} 

学习点：

1、怎么把Jtable对象和数据联系起来？答：用TableModel 

    TableModel 实现了JTable操作数据必须的一些方法，将TableModel给JTable，就是将CPU安装到主板。

2、Jtable的Header如何实现排序？答：用TableSorter 

    如果只想把TableModel给Jtable，可以直接 JTable tableView = new JTable( dataModel );

    下面的写法是为了实现表的Header排序：

   TableSorter sorter = new TableSorter(dataModel);
   JTable tableView = new JTable(sorter);
   sorter.addMouseListenerToHeaderInTable(tableView); 

    第三行的意思是在鼠标点击表头的时候实现排序，也就是说，何时触发排序可灵活配置。 

 3、frame.pack();有什么用？

答：我自己试了下，如果把 frame.pack();注释掉运行，我看到的frame是最小size的，只有仨按钮在那，需要

手动拖窗口才能看到内容。如果去掉注释，frame会根据内容的大小自动调节初始的大小。这也是这行的作用。