无法强制表始终显示滚动条，操作系统决定何时显示它们。

It's not possible to force the Table to always show scroll bars, the OS decides when to show them.

替代品

对，我想出了一个非常类似于我的解决方案回答这个问题：

Right, I came up with a solution very similar to my answer to this question:

是否可以获得垂直/水平滚动当SWT列表处于禁用状态时，栏是否可见？

想法是使用 ScrolledComposite （如已建议的另一个答案）来处理滚动。 表本身不会滚动。 然而，这不会有任何区别，因为用户无法区分。

The idea is to use a ScrolledComposite (as the other answer already suggested) to take care of the scrolling. The Table itself won't scroll. However, this won't make any difference, because the user won't be able to tell the difference.

ScrolledComposite 有一个名为 setAlwaysShowScrollBars（boolean）的方法，使用它可以强制它始终显示滚动条，即使它们不是必需的。

ScrolledComposite has a method called setAlwaysShowScrollBars(boolean) with which you can force it to always show the scroll bars, even if they aren't required.

以下是一些示例代码，它将说明我刚才谈到的内容：

Here is some sample code, that will illustrate what I just talked about:

public static void main(String[] args)
{
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setLayout(new GridLayout());

    final ScrolledComposite composite = new ScrolledComposite(shell, SWT.V_SCROLL);
    composite.setLayout(new GridLayout());
    composite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

    final Table table = new Table(composite, SWT.NO_SCROLL | SWT.FULL_SELECTION);
    table.setHeaderVisible(true);

    composite.setContent(table);
    composite.setExpandHorizontal(true);
    composite.setExpandVertical(true);
    composite.setAlwaysShowScrollBars(true);
    composite.setMinSize(table.computeSize(SWT.DEFAULT, SWT.DEFAULT));

    Button fillTable = new Button(shell, SWT.PUSH);
    fillTable.setText("Fill table");
    fillTable.setLayoutData(new GridData(SWT.FILL, SWT.END, true, false));

    fillTable.addListener(SWT.Selection, new Listener()
    {
        @Override
        public void handleEvent(Event arg0)
        {
            if (table.getColumnCount() < 1)
            {
                for (int col = 0; col < 4; col++)
                {
                    TableColumn column = new TableColumn(table, SWT.NONE);
                    column.setText("Column " + col);
                }
            }

            for (int row = 0; row < 20; row++)
            {
                TableItem item = new TableItem(table, SWT.NONE);

                for (int col = 0; col < table.getColumnCount(); col++)
                {
                    item.setText(col, "Item " + row + " " + col);
                }
            }

            for (int col = 0; col < table.getColumnCount(); col++)
            {
                table.getColumn(col).pack();
            }

            composite.setMinSize(table.computeSize(SWT.DEFAULT, SWT.DEFAULT));
        }
    });

    Button clearTable = new Button(shell, SWT.PUSH);
    clearTable.setText("Clear table");
    clearTable.setLayoutData(new GridData(SWT.FILL, SWT.END, true, false));

    clearTable.addListener(SWT.Selection, new Listener()
    {
        @Override
        public void handleEvent(Event arg0)
        {
            table.removeAll();

            composite.setMinSize(table.computeSize(SWT.DEFAULT, SWT.DEFAULT));
        }
    });

    shell.pack();
    shell.setSize(400, 300);
    shell.open();
    while (!shell.isDisposed())
    {
        if (!display.readAndDispatch())
            display.sleep();
    }
    display.dispose();
}

看起来像这样：

如您所见，滚动条始终可见。

As you can see, the scroll bar is always visible.

更新

正如评论中所指出的，向下滚动时，此方法不会保持表标题可见。如果您可以发布一个说明问题的小工作代码示例，我们可能会提出一个替代方案（与强制滚动条无关）。

As pointed out in the comment, this approach will not keep the Table headers visible when you scroll down. If you could post a small working code example that illustrates your problem, we might come up with an alternative (unrelated to forcing the scroll bars).

UPDATE2

这是一些应该做你想做的代码，诀窍就是在 TableViewer ，显示的水平滚动条不是必需的，它会在您调整窗口大小后消失：

Here is some code that should do what you want, the trick is to trigger a resize event on the parent of the TableViewer, the horizontal scrollbar that is shown isn't really necessary and it disappears after you resize the window:

public static void main(String[] args)
{
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setText("***");
    shell.setLayout(new GridLayout());

    createMasterPart(shell);

    shell.pack();
    shell.setSize(400, 300);
    shell.open();

    shell.layout(true, true);

    while (!shell.isDisposed())
    {
        if (!display.readAndDispatch())
            display.sleep();
    }
    display.dispose();
}

private static void createMasterPart(Composite parentComposite)
{
    Composite composite = new Composite(parentComposite, SWT.NONE);
    composite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));
    composite.setLayout(new GridLayout(1, false));

    Composite tableComposite = new Composite(composite, SWT.NONE);
    TableColumnLayout tableColumnLayout = new TableColumnLayout();
    tableComposite.setLayout(tableColumnLayout);
    tableComposite.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, true));

    TableViewer tableViewer = new TableViewer(tableComposite, SWT.BORDER | SWT.FULL_SELECTION);
    tableViewer.setContentProvider(ArrayContentProvider.getInstance());
    Table table = tableViewer.getTable();
    table.setHeaderVisible(true);
    table.setLinesVisible(true);

    TableViewerColumn firstTableViewerColumn = new TableViewerColumn(tableViewer, SWT.NONE);
    TableColumn firstTableColumn = firstTableViewerColumn.getColumn();
    firstTableColumn.setText("Sample");
    firstTableViewerColumn.setLabelProvider(new ColumnLabelProvider()
    {
        @Override
        public String getText(Object element)
        {
            Dummy p = (Dummy) element;
            return p.first;
        }
    });

    TableViewerColumn secondTableViewerColumn = new TableViewerColumn(tableViewer, SWT.NONE);
    TableColumn secondTableColumn = secondTableViewerColumn.getColumn();
    secondTableColumn.setText("Speaker");
    secondTableViewerColumn.setLabelProvider(new ColumnLabelProvider()
    {
        @Override
        public String getText(Object element)
        {
            Dummy p = (Dummy) element;
            return p.second;
        }
    });

    TableViewerColumn thirdTableViewerColumn = new TableViewerColumn(tableViewer, SWT.NONE);
    TableColumn thirdTableColumn = thirdTableViewerColumn.getColumn();
    thirdTableColumn.setText("Remark");
    thirdTableViewerColumn.setLabelProvider(new ColumnLabelProvider()
    {
        @Override
        public String getText(Object element)
        {
            Dummy p = (Dummy) element;
            return p.third;
        }
    });

    List<Dummy> elements = new ArrayList<>();

    for(int i = 0; i < 20; i++)
    {
        elements.add(new Dummy("firstfirstfirst " + i, "secondsecondsecond " + i, "thirdthirdthirdthirdthirdthird " + i));
    }

    tableViewer.setInput(elements);

    tableColumnLayout.setColumnData(firstTableColumn, new ColumnWeightData(1, true));
    tableColumnLayout.setColumnData(secondTableColumn, new ColumnWeightData(1, true));
    tableColumnLayout.setColumnData(thirdTableColumn, new ColumnWeightData(2, true));
}

private static class Dummy
{
    public String first;
    public String second;
    public String third;

    public Dummy(String first, String second, String third)
    {
        this.first = first;
        this.second = second;
        this.third = third;
    }
}