AbstractTableModel生产ClassCastException

Question

有人能发现这个代码有什么问题吗？我要让"java.lang.ClassCastException: java.lang.String不能被投给java.lang.Boolean。“

class MyTableModel extends AbstractTableModel {
    private String[] columnNames = {"Name","State","Start","Stop","Terminate"};
    private List<Row> rows = new ArrayList<Row>();

    @Override
    public int getColumnCount() {
        return columnNames.length;
    }

    @Override
    public int getRowCount() {
        return rows.size();
    }

    public String getColumnName(int col) {
        return columnNames[col];
    }

    @Override
    public Object getValueAt(int row, int col) {
        Row targetRow = rows.get(row);
        switch (col) { 
            case 1: return targetRow.name;
            case 2: return targetRow.state;
            case 3: return targetRow.start;
            case 4: return targetRow.stop;
            case 5: return targetRow.terminate;
        }
        return null;
    }

    /*
     * JTable uses this method to determine the default renderer/
     * editor for each cell.  If we didn't implement this method,
     * then the last column would contain text ("true"/"false"),
     * rather than a check box.
     */
    @Override
    public Class<?> getColumnClass(int c) {
        Class[] colTypes = new Class[]{String.class,String.class,Boolean.class,Boolean.class,Boolean.class};
        return colTypes[c];
    }

    @Override
    public boolean isCellEditable(int row, int col) {

        String state = (String)getValueAt(row,1);
        if (state.equals("running")) {      //instance is running
            if (col==2) return false;       //disable start checkbox if already running
            else if (col>2) return true;    //enable stop and terminate
        }
        else {                                      //instance is stopped
            if (col==3) return false;               //disable stop checkbox
            else if (col==2 || col==4) return true; //enable start and terminate
        }
        return false;
    }

    @Override
    public void setValueAt(Object value, int row, int col) {
        Row targetRow = rows.get(row);
        switch (col) {
            case 1: targetRow.name      = (String)value;  break;
            case 2: targetRow.state     = (String)value;  break;
            case 3: targetRow.start     = (Boolean)value; break;
            case 4: targetRow.stop      = (Boolean)value; break;
            case 5: targetRow.terminate = (Boolean)value; break;
        }
        fireTableCellUpdated(row, col);
    }

    public void addRow(String name, String state) {
        Row row = new Row(name,state);
        rows.add(row);
    }

    private class Row {
        String  name;
        String  state;
        Boolean start;
        Boolean stop;
        Boolean terminate;

        public Row(String name, String state) {
            this.name = name;
            this.state = state;
            this.start = new Boolean(false);
            this.stop = new Boolean(false);
            this.terminate = new Boolean(false);
        }
    }
}

下面是实现它的方法：

private void initTable() {
    tbInstances = new JTable(new MyTableModel());
    tbInstances.setPreferredScrollableViewportSize(new Dimension(500, 70));
    tbInstances.setFillsViewportHeight(true);
    populateInstancesTable();

    //Create the scroll pane and add the table to it.
    JScrollPane scrollPane = new JScrollPane(tbInstances);
    tabStartStop.setLayout(new BorderLayout());
    tabStartStop.add(scrollPane);
}

下面是填充表的代码。实例是在其他地方填充的ArrayList。

private void populateInstancesTable() {
    String name = null;
    for (Instance instance:instances) {
        List<Tag> tags = instance.getTags();
        for (Tag tag: tags) {
            if (tag.getKey().equals("Name")) {
                name = tag.getValue();
                break;
            }
        }
        String state = instance.getState().getName();
        if (name.contains("_e360")) {
            MyTableModel model = (MyTableModel)tbInstances.getModel();
            model.addRow(name,state);
            System.out.println("added row: name="+name+", state="+state);
        }
    }
}

有什么想法吗？

下面是堆栈跟踪：

添加行: name=Acme_e360_server，state=running

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Boolean
    at javax.swing.plaf.synth.SynthTableUI$SynthBooleanTableCellRenderer.getTableCellRendererComponent(SynthTableUI.java:730)
    at javax.swing.JTable.prepareRenderer(JTable.java:5723) 
    at javax.swing.plaf.synth.SynthTableUI.paintCell(SynthTableUI.java:683)
    at javax.swing.plaf.synth.SynthTableUI.paintCells(SynthTableUI.java:580)
    at javax.swing.plaf.synth.SynthTableUI.paint(SynthTableUI.java:364)
    at javax.swing.plaf.synth.SynthTableUI.update(SynthTableUI.java:275)
    at javax.swing.JComponent.paintComponent(JComponent.java:780)
    at javax.swing.JComponent.paint(JComponent.java:1056)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JViewport.paint(JViewport.java:728)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5210)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1579)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1502)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1272)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5158)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4969)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:831)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:814)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738)
    at javax.swing.RepaintManager.access$1200(RepaintManager.java:64)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Boolean
    at javax.swing.plaf.synth.SynthTableUI$SynthBooleanTableCellRenderer.getTableCellRendererComponent(SynthTableUI.java:730)
    at javax.swing.JTable.prepareRenderer(JTable.java:5723)
    at javax.swing.plaf.synth.SynthTableUI.paintCell(SynthTableUI.java:683)
    at javax.swing.plaf.synth.SynthTableUI.paintCells(SynthTableUI.java:580)
    at javax.swing.plaf.synth.SynthTableUI.paint(SynthTableUI.java:364)
    at javax.swing.plaf.synth.SynthTableUI.update(SynthTableUI.java:275)
    at javax.swing.JComponent.paintComponent(JComponent.java:780)
    at javax.swing.JComponent.paint(JComponent.java:1056)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JViewport.paint(JViewport.java:728)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5210)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1579)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1502)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1272)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5158)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4969)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:831)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:814)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738)
    at javax.swing.RepaintManager.access$1200(RepaintManager.java:64)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Boolean
    at javax.swing.plaf.synth.SynthTableUI$SynthBooleanTableCellRenderer.getTableCellRendererComponent(SynthTableUI.java:730)
    at javax.swing.JTable.prepareRenderer(JTable.java:5723)
    at javax.swing.plaf.synth.SynthTableUI.paintCell(SynthTableUI.java:683)
    at javax.swing.plaf.synth.SynthTableUI.paintCells(SynthTableUI.java:580)
    at javax.swing.plaf.synth.SynthTableUI.paint(SynthTableUI.java:364)
    at javax.swing.plaf.synth.SynthTableUI.update(SynthTableUI.java:275)
    at javax.swing.JComponent.paintComponent(JComponent.java:780)
    at javax.swing.JComponent.paint(JComponent.java:1056)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JViewport.paint(JViewport.java:728)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintChildren(JComponent.java:889)
    at javax.swing.JComponent.paint(JComponent.java:1065)
    at javax.swing.JComponent.paintToOffscreen(JComponent.java:5210)
    at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1579)
    at javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1502)
    at javax.swing.RepaintManager.paint(RepaintManager.java:1272)
    at javax.swing.JComponent._paintImmediately(JComponent.java:5158)
    at javax.swing.JComponent.paintImmediately(JComponent.java:4969)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:831)
    at javax.swing.RepaintManager$4.run(RepaintManager.java:814)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:814)
    at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:789)
    at javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:738)
    at javax.swing.RepaintManager.access$1200(RepaintManager.java:64)
    at javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1732)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

Answer 1

getValueAt和setValueAt方法错误地期望第一列为1，第一列编号为0。

这意味着您实际上没有返回第2列的布尔值，尽管您的getColumnClass方法告诉Swing期待第2列的布尔值。