您的第一个片段显示如下：
JTable table = new JTable(model);
但您的
gui()构造函数显示：
JTable table = new JTable(data, columnNames);
您两次启动表。一旦使用
TableModel（
JTable(TableModeltm)），则下一次使用
JTable(introws,intcols)该方法不好，请
JTable在构造函数中初始化一次：
gui() {DefaultTableModel model = new DefaultTableModel(data,columnNames);JTable table = new JTable(model);JScrollPane scrollPane = new JScrollPane(table);JButton next = new JButton("next");JButton prev = new JButton("prev");next.addActionListener(this);prev.addActionListener(this);JPanel panel = new JPanel(new BorderLayout());JPanel buttonPanel = new JPanel();buttonPanel.add(prev);buttonPanel.add(next);panel.add(buttonPanel, BorderLayout.SOUTH);panel.add(table.getTableHeader(), BorderLayout.PAGE_START);panel.add(scrollPane, BorderLayout.CENTER);getContentPane().add(panel);}更新：
这是一个示例，该示例具有一个线程，该线程将在显示UI后启动2.5秒，并更改的值
JTable：
import java.util.logging.Level;import java.util.logging.Logger;import javax.swing.*;import javax.swing.table.DefaultTableModel;public class Test extends Jframe { public static void main(String[] args) throws Exception { SwingUtilities.invokeLater(new Runnable() { @Override public void run() { new Test().createAndShowUI(); } }); } private void createAndShowUI() { Jframe frame = new Jframe(); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); initComponents(frame); frame.pack(); frame.setVisible(true); new Thread(new Runnable() { @Override public void run() { try { Thread.sleep(2500); } catch (InterruptedException ex) { Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex); } SwingUtilities.invokeLater(new Runnable() { @Override public void run() { model.setValueAt("hello", 0, 0); } }); } }).start(); } static DefaultTableModel model; private void initComponents(Jframe frame) { String data[][] = { {"1", "2", "3"}, {"4", "5", "6"}, {"7", "8", "9"}, {"10", "11", "12"} }; String col[] = {"Col 1", "Col 2", "Col 3"}; model = new DefaultTableModel(data, col); JTable table = new JTable(model); frame.getContentPane().add(new JScrollPane(table)); }}
