这是小弟编的，现在缺一个main函数，求大神给补上，谢谢

Question

public class yggh extends JFrame{public yggh(){super();final BorderLayout borderLayout=new BorderLayout();setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);borderLayout.setVgap(10);getContentPane().setLayout(borderLayout);setTitle("图书馆管理系统登录");Toolkit tool=Toolkit.getDefaultToolkit();Dimension screenSize=tool.getScreenSize();setSize(285,194);setLocation((screenSize.width-getWidth())/2,(screenSize.height - getHeight())/2 - 100);final JPanel mainPanel=new JPanel();mainPanel.setLayout(new BorderLayout());mainPanel.setBorder(new EmptyBorder(0, 0, 0, 0));getContentPane().add(mainPanel);final JLabel imageLabel=new JLabel();ImageIcon loginIcon=CreatecdIcon.add("login.jpg")\imageLabel.setIcon(loginIcon);imageLabel.setOpaque(true);imageLabel.setBackground(Color.GREEN);imageLabel.setPreferredSize(new Dimension(260,60));mainPanel.add(imageLabel,BorderLayout.NORTH);final JPanel centerPanel=new JPanel();final GridLayout gridLayout=new GridLayout(2,2);gridLayout.setHgap(5);gridLayout.setVgap(20);centerPanel.setLayout(gridLayout);mainPanel.add(centerPanel);final JLabel ueserNamelabel=new JLabel();}}public static void main(String[]){}

Answer 1

package xxx;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Toolkit;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;

public class yggh extends JFrame{
public yggh(){
super();
final BorderLayout borderLayout=new BorderLayout();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
borderLayout.setVgap(10);
getContentPane().setLayout(borderLayout);
setTitle("图书馆管理系统登录");
Toolkit tool=Toolkit.getDefaultToolkit();
Dimension screenSize=tool.getScreenSize();
setSize(285,194);
setLocation((screenSize.width-getWidth())/2,
(screenSize.height - getHeight())/2 - 100);

final JPanel mainPanel=new JPanel();
mainPanel.setLayout(new BorderLayout());
mainPanel.setBorder(new EmptyBorder(0, 0, 0, 0));
getContentPane().add(mainPanel);

final JLabel imageLabel=new JLabel();
//ImageIcon loginIcon=CreatecdIcon.add("login.jpg");
//imageLabel.setIcon(loginIcon);
imageLabel.setOpaque(true);
imageLabel.setBackground(Color.GREEN);
imageLabel.setPreferredSize(new Dimension(260,60));
mainPanel.add(imageLabel,BorderLayout.NORTH);

final JPanel centerPanel=new JPanel();
final GridLayout gridLayout=new GridLayout(2,2);
gridLayout.setHgap(5);
gridLayout.setVgap(20);
centerPanel.setLayout(gridLayout);
mainPanel.add(centerPanel);
final JLabel ueserNamelabel=new JLabel();

}

public static void main(String ag[]){
(new yggh()).setVisible(true);
}

}

Answer 2

public static void main(String[]){
new yggh();
}