java中一个小程序中的组件显示不出来解决方案

package PasswordManeger;

import java.awt.Container;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;

public class LogInWindows  extends JFrame implements ActionListener
{
	private Function functionclass=new Function();
	
	private String urlofimagetoshow="C:\\Users\\lenovo\\Desktop\\信息管理器\\show.jpg";
	private String urloficon="C:\\Users\\lenovo\\Desktop\\信息管理器\\login.jpg";
	
	private Image icon;
	private Image imagetoshow;
	
	private JLabel  idlabel;
	private JLabel passwordlabel;
	
	private  JTextField idtextfield;
	private  JTextField passwordtextfield;
	
	private JButton loginbutton;
	
	private Container  container;
	
	public LogInWindows()
	{
		super("密码管理器");
		container=new Container();
		container=getContentPane();
		
		container.setLayout(null);
		
		icon=getToolkit().getImage(urloficon);
		setIconImage(icon);
		
		imagetoshow=getToolkit().getImage(urlofimagetoshow);
		
		setVisible(true);//if you don't  add it,there  will  a  mistake  when  show  the login window
		
		Graphics graphics=this.getGraphics();
		
		idlabel=new JLabel("账号");
		idlabel.setBounds(100,200,50,20);
		container.add(idlabel);
		
		passwordlabel=new JLabel("密码");
		passwordlabel.setBounds(100,250,50,20);
		container.add(passwordlabel);
		
		idtextfield=new JTextField();
		idtextfield.setBounds(200,200,100,20);
		container.add(idtextfield);
		
		passwordtextfield=new JTextField();
		passwordtextfield.setBounds(200,250,100,20);
		container.add(passwordtextfield);
		
		loginbutton=new JButton("登录");
		loginbutton.setBounds(220,270,30,20);
		loginbutton.addActionListener(this);
		container.add(loginbutton);
		
		
		paint(graphics);// is it  right?
		setSize(500,400);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setVisible(true);
		

	}
	
	public void actionPerformed(ActionEvent e)
	{
		boolean idexist=false;
		String sql="select * from INFORMATIONOFUSER;";
		String dbdriver="oracle.jdbc.driver.OracleDriver";
		String dburl="jdbc:oracle:thin:@localhost:1521:orcl";
		String dbuser="scott";
		String dbpassword="123456";
		
		String passwordofuser="";
		
		try {
			Class.forName(dbdriver);
			Connection dataconnection=DriverManager.getConnection(dburl, dbuser, dbpassword);
			Statement statement=dataconnection.createStatement();
			ResultSet result=statement.executeQuery(sql);
			do
			{
				if(result.getString(1)==idtextfield.getText())
				{
					idexist=true;
					passwordofuser=result.getString(2);
					break;
				}
			}while(result.next());
			
			if(idexist==true||passwordtextfield.getText()==passwordofuser)
			{
				functionclass.setVisible(true);
			}
			else
			{
				JOptionPane.showMessageDialog(this,"账号或者密码错误");
			}
		}
		catch (ClassNotFoundException e1) {
			// TODO 自动生成的 catch 块
			e1.printStackTrace();
		}
		catch (SQLException e1) {
			// TODO 自动生成的 catch 块
			e1.printStackTrace();
		}
	}
	
	public void paint(Graphics g)
	{
		g.drawImage(imagetoshow, 0, 0,500,150,this);
	
	}
}

private Function functionclass=new Function();