Java JTable/DefaultTableModel java.lang.ArrayIndexOutOfBoundsException

Question

在我的应用程序中，我正在使用包含 DefaultTableModel 的 JTable。一切都工作正常，直到我想清除我的表并从新的 DefaultTableModel 开始。清算过程是这样完成的:

public static JTable table = new JTable;
public static CustomTableModel model = new CustomTableModel();

[...]

table.setModel(new DefaultTableModel());
model = new CustomTableModel();
model.createEmptyModel();
table.setModel(model); 
// model.save(config.getDatabaseFile(), table); // <<< Reference A
model.initColumModel(table);

到目前为止一切顺利。现在，我的 CustomTableModel 从 DefaulTableModel 扩展并添加了一些自定义方法。其中之一是 createEmptyModel() ，如下所示:

public void createEmptyModel() {
    model = new DefaultTableModel(new Object[][] {},
            new String[] { "Lfd. Nr.", "FB Nr.", "Auftr. / Meld. Nr.", "Betra Nr.", "Datum", "Bahnhof", "Str. Km.",
                    "Sprz.", "Arb. Zeit", "Mitarbeiter", "Auftrag / Objekt(e)", "Anmerkungen", "Fertig" }) {

        private static final long serialVersionUID = -4325766838779239822L;
        @SuppressWarnings("rawtypes")
        Class[] columnTypes = new Class[] { Integer.class, String.class, Long.class, Long.class, String.class,
                String.class, String.class, String.class, String.class, String.class, String.class, String.class, Boolean.class };

        @SuppressWarnings({ "unchecked", "rawtypes" })
        public Class getColumnClass(int columnIndex) {
            return columnTypes[columnIndex];
        }
    };
    // this sequentialNumber is just some object which contains a counter. Not important here!
    sequentialNumber.reset();
}

通过这种方法，我使用所有需要的 vector 和类型初始化模型。

当调用 model.initColumModel(table) get 时，我的应用程序因以下异常而崩溃:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 0 >= 0
    at java.util.Vector.elementAt(Unknown Source)
    at javax.swing.table.DefaultTableColumnModel.getColumn(Unknown Source)
    at somepacket.CustomTableModel.initColumModel(CustomTableModel.java:36)
    at somepacket.DBDatabaseSystem.createNewDatabase(DBDatabaseSystem.java:416)
    at somepacket.DBDatabaseSystem$4.actionPerformed(DBDatabaseSystem.java:155)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    at javax.swing.AbstractButton.doClick(Unknown Source)
    at javax.swing.plaf.basic.BasicMenuItemUI.doClick(Unknown Source)
    at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(Unknown Source)
    at java.awt.Component.processMouseEvent(Unknown Source)
    at javax.swing.JComponent.processMouseEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access$500(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.awt.EventQueue$3.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.awt.EventQueue$4.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
    at java.awt.EventQueue.dispatchEvent(Unknown Source)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
    at java.awt.EventDispatchThread.run(Unknown Source)

我的initColumModel方法声明如下:

public void initColumModel(JTable table) {
    // doing this here to avoid calling table.getColumnModel multiple times
    TableColumnModel columnModel = table.getColumnModel();

    columnModel.getColumn(0).setResizable(false);
    columnModel.getColumn(0).setPreferredWidth(50);
    columnModel.getColumn(1).setResizable(false);
    columnModel.getColumn(1).setPreferredWidth(50);
    columnModel.getColumn(2).setResizable(false);
    columnModel.getColumn(2).setPreferredWidth(81);
    columnModel.getColumn(3).setResizable(false);
    columnModel.getColumn(3).setPreferredWidth(81);
    columnModel.getColumn(4).setPreferredWidth(81);
    columnModel.getColumn(5).setPreferredWidth(134);
    columnModel.getColumn(6).setPreferredWidth(123);
    columnModel.getColumn(7).setPreferredWidth(95);
    columnModel.getColumn(8).setPreferredWidth(95);
    columnModel.getColumn(9).setPreferredWidth(226);
    columnModel.getColumn(10).setResizable(true);
    columnModel.getColumn(10).setPreferredWidth(300);
    columnModel.getColumn(11).setResizable(true);
    columnModel.getColumn(11).setPreferredWidth(102);
    columnModel.getColumn(12).setResizable(false);
    columnModel.getColumn(12).setMinWidth(45);
    columnModel.getColumn(12).setMaxWidth(45);
}

据我所知，问题是我的 CustomTableModel 创建后没有列。所以我尝试的是向表中添加一个新行，然后调用 initColumModel ，但这没有帮助。应用程序仍然崩溃。防止崩溃的唯一方法是在调用 initColumModel 方法之前保存模型。但这没有意义，你自己看看，这是我的保存方法，它不会改变模型上的任何内容，也不会添加任何列:

[...]

    try {
            // undo all selections to prevent user from editing while saving
            table.clearSelection(); 
            // prevent saving when user is editing a cell
            if (table.isEditing()) { 
                table.getCellEditor().stopCellEditing();
            }

            fos = new FileOutputStream(filename);
            out = new ObjectOutputStream(fos);

            table.setModel(new DefaultTableModel());
            // detach model from table prior serializing
            out.writeObject(model);
            // re-attach table model
            table.setModel(model); 
            // set layout again
            initColumModel(table); 

            out.writeObject(sequentialNumber);

[...]

保存模型后，它会出现在 JTable 中，并且一切正常。怎么会这样？在调用 initColumModel 之前，我尝试手动从表中分离并重新附加模型，但这也没有帮助。

基本上我现在迷失了，我该如何解决我的问题？还是我做了一些明显错误的事情？

提前致谢!

Answer 1

如果您只想清除模型中的数据，那么您只需使用:

model.setRowCount(0);

如果您想用新的结构(即新的列标题和数据)替换 TableModel，那么您只需创建一个新的 TableModel:

TableModel model = new DefaultTableModel(...);
table.setModel( model );

From what I can the problem is that my CustomTableModel has no columns after it's creation

如果正确实现 getColumnCount() 和 getColumnNames() 方法，它肯定有列。

在您实际为表设置模型之前，不会创建 JTable 的 TableColumnModel。当您使用 new DefaultTableModel() 时，您将创建一个具有零列的 TableColumnModel。因此，如果您希望存在列，请向表中添加适当的 TableModel。

// detach model from table prior serializing

为什么要把模型从 table 上拆下来？这是不必要的。

您可能希望使用 XMLEncoder 来代替序列化 DefaultTableModel，这是长期存储对象的推荐方法。请参阅:Saving content of Interactive JTable to .txt file to read it upon next run有关此方法的工作示例。