引入文件:import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.KeyStroke;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;import java.util.Date;
import java.text.SimpleDateFormat; 
我想给一个Panel 变量L设置标题
老是报错提示:C:\JavaEx\FrameGUI.java:87: 找不到符号
符号: 方法 setBorder(javax.swing.border.TitledBorder)
位置: 类 java.awt.Panel
        p11.setBorder(new TitledBorder(null,"房务状态",TitledBorder.DEFAULT_JUSTIFICATION, TitledBorder.DEFAULT_POSITION,null,Color.red));
                   ^
C:\JavaEx\FrameGUI.java:88: 找不到符号
符号: 方法 setBorder(javax.swing.border.TitledBorder)
位置: 类 java.awt.Panel
        p12.setBorder(new TitledBorder(new EtchedBorder(),"当前时间"));
                   ^
C:\JavaEx\FrameGUI.java:89: 找不到符号
符号: 方法 setBorder(javax.swing.border.TitledBorder)
位置: 类 java.awt.Panel
        p13.setBorder(new TitledBorder(new EtchedBorder(),"等待修改"));
                   ^
C:\JavaEx\FrameGUI.java:90: 找不到符号
符号: 方法 setBorder(javax.swing.border.TitledBorder)
位置: 类 java.awt.Panel
        p14.setBorder(new TitledBorder(new EtchedBorder(),"总房态"));
                   ^
4 错误 ————————————》》》 请问这是怎么回事????????