需求：准备写一个jtable然后更改她的样式后续所有的table都继承这个jtable；
问题：展现出来的table无column列名称；
代码展现：
package gov.service.product.gfmis.ResultDialogModel;

import gov.
import gov.
import gov.service.product.gfmis.balance.ui.BalanceMainUI;
import gov.service.product.

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.event.WindowEvent;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;

import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.JTableHeader;

public class Test extends JTable{
   
    private static GeneralDAO dao = ComponentManager.generalDAO;
   

    public Test()
    {   
        JScrollPane jsp=new JScrollPane();
        jsp.setViewportView(this);
      
      table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
        table.setRowHeight(20);
        table.setFont(new Font("微软儒雅",Font.PLAIN,14));
        
        int columnCount=table.getColumnModel().getColumnCount();
        System.out.println(columnCount);
        for(int i=0;i<columnCount;i++)
        {
            int width=table.getColumnModel().getColumn(i).getWidth();
            table.getColumnModel().getColumn(i).setPreferredWidth(width+20);
        }
        
        JTableHeader head=new JTableHeader();
        head.setFont(new Font("微软雅黑",Font.PLAIN,16));
        head.setPreferredSize(new Dimension(head.getWidth(),25));
         
        getModel();
    }
    protected void getModel() {
        ThreadGroup group = Thread.currentThread().getThreadGroup();// 获得当前线程所在线程组
        Thread[] threads = new Thread[group.activeCount()];// 使用数组保存活动状态的线程
        group.enumerate(threads);// 获得所有线程
        DefaultTableModel model = (DefaultTableModel) this.getModel(); // 获得表格模型
        model.setRowCount(0); // 清空表格模型中的数据
        model.setColumnIdentifiers(new Object[] { "线程ID", "线程名称", "优先级" }); // 定义表头
        for (Thread thread : threads) {// 增加行数据
            model.addRow(new Object[] { thread.getId(), thread.getName(), thread.getPriority() });
        }
        this.setModel(model);// 更新表格模型
    }
   
    public static void main(String[] args) {

        try {
            UIManager
                    .setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (Throwable e) {
            e.printStackTrace();
        }

        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.setBounds(100, 100, 800, 300);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                JPanel content=new JPanel();
                content.add(new Test());
                frame.setContentPane(content);
                frame.setVisible(true);
                frame.setResizable(true);
            }
        });

    }

}

展现结果：见附件

这个是有值的，我在setModel()之后在获取model循环打印columnName都是可以的。可是显示的时候就是没有