4。2 设计代码Java 源程序:import java 。awt.*;import java.awt 。event。*;import javax 。swing。*;import java 。awt。*;import java.sql. *;import java.lang. *; import java 。util.*; import javax 。swing。table。*;import java.math. *; class DB_LS implements ActionListener{JFrame frame=new JFrame (”欢迎进入 LS 工资管理系统”);JLabel label=new JLabel ("09 网络 2_54_李胜”,JLabel.CENTER );JButton button1=new JButton ("进入系统");JButton button2=new JButton(" 退出系统”);ImageIcon im=new ImageIcon ("1。jpg"); JLabel a1=new JLabel (im);void Create (){JPanel pcontentPane=(JPanel )frame。getContentPane();JPanel pcontentPane1=new JPanel ();pcontentPane.add (label);pcontentPane 。setLayout (new FlowLayout ());pcontentPane.add (button1 );pcontentPane 。add(button2 );pcontentPane.add (new Label (" ” ));pcontentPane 。add(a1);pcontentPane 。setBackground (Color.green) ;pcontentPane.setVisible(true );button1.addActionListener(this ); button2.addActionListener(this );frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE );frame。pack();frame。setBounds (200,100,550,600 );frame。setVisible(true) ;}public static void main(String [] args){DB_LS dome=new DB_LS( );dome.Create() ;} public void actionPerformed(ActionEvent e){ if(button1 。equals(e 。getSource() )){ DL dl=new DL(); dl.create (); } if(button2.equals (e.getSource())) {//退出System.exit (0);} }} class DL implements ActionListener {JFrame frame=new JFrame(" 职工/管理员登陆");JLabel label1=new JLabel(" 用户名”);JLabel label2=new JLabel(" 密码");JButton logonButton1=new JButton(” 管理员登录");JButton logonButton2=new JButton ("职工登录”);JButton cancelButton=new JButton (”退出”);JTextField t1=new JTextField(0);JTextField t2=new JTextField (0);ImageIcon im=new ImageIcon("2 。jpg"); JLabel a2...