cannot resolve symbol:的提示，如何解决？

[Gooder]

public class xcgjFrame extends JFrame {
JPanel contentPane;
JMenuBar jMenuBar1 = new JMenuBar();
JMenu jMenuFile = new JMenu();
JMenuItem jMenuFileExit = new JMenuItem();
JMenu jMenuHelp = new JMenu();
JMenuItem jMenuHelpAbout = new JMenuItem();
JToolBar jToolBar = new JToolBar();
JButton jButton1 = new JButton();
JButton jButton2 = new JButton();
JButton jButton3 = new JButton();
ImageIcon image1;
ImageIcon image2;
ImageIcon image3;
JLabel statusBar = new JLabel();
BorderLayout borderLayout1 = new BorderLayout();

//Construct the frame
public xcgjFrame() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
//Component initialization
private void jbInit() throws Exception {
//出错 image1 = new ImageIcon(xcgj.xcgjFrame.class.getResource("openFile.png"));
//出错 image2 = new ImageIcon(xcgj.xcgjFrame.class.getResource("closeFile.png"));
//出错 image3 = new ImageIcon(xcgj.xcgjFrame.class.getResource("help.png"));
contentPane = (JPanel) this.getContentPane();
contentPane.setLayout(borderLayout1);
this.setSize(new Dimension(400, 300));
this.setTitle("小仓管");
statusBar.setText(" ");
jMenuFile.setText("File");
jMenuFileExit.setText("Exit");
jMenuFileExit.addActionListener(new xcgjFrame_jMenuFileExit_ActionAdapter(this));
jMenuHelp.setText("Help");
jMenuHelpAbout.setText("About");
jMenuHelpAbout.addActionListener(new xcgjFrame_jMenuHelpAbout_ActionAdapter(this));
jButton1.setIcon(image1);
jButton1.setToolTipText("Open File");
jButton2.setIcon(image2);
jButton2.setToolTipText("Close File");
jButton3.setIcon(image3);
jButton3.setToolTipText("Help");
jToolBar.add(jButton1);
jToolBar.add(jButton2);
jToolBar.add(jButton3);
jMenuFile.add(jMenuFileExit);
jMenuHelp.add(jMenuHelpAbout);
jMenuBar1.add(jMenuFile);
jMenuBar1.add(jMenuHelp);
this.setJMenuBar(jMenuBar1);
contentPane.add(jToolBar, BorderLayout.NORTH);
contentPane.add(statusBar, BorderLayout.SOUTH);
}
//File | Exit action performed
public void jMenuFileExit_actionPerformed(ActionEvent e) {
System.exit(0);
}
//Help | About action performed
public void jMenuHelpAbout_actionPerformed(ActionEvent e) {
xcgjFrame_AboutBox dlg = new xcgjFrame_AboutBox(this);
Dimension dlgSize = dlg.getPreferredSize();
Dimension frmSize = getSize();
Point loc = getLocation();
dlg.setLocation((frmSize.width - dlgSize.width) / 2 + loc.x, (frmSize.height - dlgSize.height) / 2 + loc.y);
dlg.setModal(true);
dlg.pack();
dlg.show();
}
//Overridden so we can exit when window is closed
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if (e.getID() == WindowEvent.WINDOW_CLOSING) {
jMenuFileExit_actionPerformed(null);
}
}
}


为什么我在标有"//出错"的地方会有
cannot resolve symbol: class xcgjFrame in class
的提示？

[w1w1w1w]

给你个例子。
public class ImageResource {
public static Icon getBtnIcon(Frame frame,String icoUrl){
URL url = frame.getClass().getResource(icoUrl);
Icon ico = new ImageIcon(url);
return ico;
}
}

调用：
//img文件夹在classes目录下
jButton.setIcon(com.lyq.pub.ImageResource.getBtnIcon(this,"/img/001.gif"));