logon.java

图书管理系统v1.0是使用JAVA语言开发的解决图书基本管理的一个应用程序。 该系统能够实现简单的图书和用户管理

package lib;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
import java.util.*;
import java.text.*;

public class Logon extends JFrame implements ActionListener {

	private Dimension d = Toolkit.getDefaultToolkit().getScreenSize();	//Getting the User's Screen Dimensions.

	private JPanel pLog = new JPanel();
	private JLabel lbUser, lbPass,lbType;
	private JTextField txtUser;
	private JPasswordField txtPass;
	private JButton btnOk, btnCancel;
	private JComboBox cb;
	private String[] userType = {"管理员","用户"};
	
	public Logon () {

		//Setting Program's Title.

		super ("图书系统 v1.0");

		//Setting the Main Window of Program.

		setIconImage (getToolkit().getImage ("Images/Host16.gif"));	//Setting the Program's Icon.
		setSize (275, 200);						//Setting Main Window Size.
		setResizable (false);						//Make it UnResizeable.

		//Closing Code of Main Window.

		addWindowListener (new WindowAdapter () {		//Attaching the WindowListener to Program.
			public void windowClosing (WindowEvent we) {	//Overriding the windowClosing Function.
				setVisible (false);			//Hide the Form.
				dispose();            			//Free the System Resources.
				System.exit (0);        		//Close the Application.
			}
		}
		);

		//Setting the Logon Form Position on User's Screen.

		setLocation (d.width / 2 - getWidth() / 2, d.height / 2 - getHeight() / 2);

		//Setting the Layout of Panel.

		pLog.setLayout (null);

		//Setting the Form's Labels.

		lbUser = new JLabel ("ID号码:");
		lbUser.setForeground (Color.black);
		lbUser.setBounds (20, 55, 75, 25);
	        lbPass = new JLabel ("密码:");
		lbPass.setForeground (Color.black);
        	lbPass.setBounds (20, 90, 75, 25);

		//Setting the Form's TextField & PasswordField.

		txtUser = new JTextField ();
		txtUser.setBounds (100, 55, 150, 25);
		txtPass = new JPasswordField ();
		txtPass.setBounds (100, 90, 150, 25);

		//Setting the Form's Buttons.

		btnOk = new JButton ("确定");
		btnOk.setBounds (20, 130, 100, 25);
		btnOk.addActionListener (this);
		btnCancel = new JButton ("取消");
		btnCancel.setBounds (150, 130, 100, 25);
		btnCancel.addActionListener (this);

		//Setting the ComboBox.
		lbType = new JLabel("登陆方式：");
		lbType.setBounds(20,15,75,25);
		cb = new JComboBox (userType);
		cb.setBounds(100, 15, 150, 25);
		//Adding All the Controls in Panel.
		pLog.add(lbType);
		pLog.add (cb);
		pLog.add (lbUser);
		pLog.add (lbPass);
		pLog.add (txtUser);
		pLog.add (txtPass);
		pLog.add (btnOk);
		pLog.add (btnCancel);

		getContentPane().add (pLog);
		setVisible (true);

	}

	public void actionPerformed (ActionEvent ae) {

		Object obj = ae.getSource();

		if (obj == btnOk) {		//If OK Button Pressed.

			String password = new String (txtPass.getPassword());

			if (txtUser.getText().equals ("")) {
				JOptionPane.showMessageDialog (this, "请填写ID号码");
				txtUser.requestFocus();
			}
			else if (password.equals ("")) {
				txtPass.requestFocus();
				JOptionPane.showMessageDialog (null,"请输入密码");
			}
			else {
			    String type;
			    String id;
				String username = "'" + (String)txtUser.getText().trim() + "'";
				boolean verify = false;		//To Confirm Logon.
				Members member = new Members();
				if(cb.getSelectedItem().toString() == "管理员") {type = "Admin";member.setType(false);id="ID";}
				else {type = "Members";member.setType(true);id="MemberID";}
					String memberQuery = "SELECT * " +
					        " FROM "+type+" WHERE " + id + " LIKE " + username;
				member.connection(memberQuery);
 			   String user = member.getName();		//Storing UserName.
				String pass = member.getPassword();		//Storing Password.
				if(member.getType()==true&&member.getMemberID()!=0||member.getType()==false&&member.getName()!=null){
					if (password.equals (pass)) {//If Found then.
						verify = true;
						setVisible (false);		//Hide the Form.
						new JLibrary(member.getType(),user);
						dispose();            		//Free the System Resources.
					}
					else {
						verify = false;
						JOptionPane.showMessageDialog (this, "密码错误！请重新输入。");
						txtUser.setText ("");
						txtPass.setText ("");
						txtUser.requestFocus ();
					}
				}
				else
					JOptionPane.showMessageDialog(null, "ID号码不存在！", "Warning", JOptionPane.WARNING_MESSAGE);
			}
		}
		else if (obj == btnCancel) {		//If Cancel Button Pressed Unload the From.
			setVisible (false);
			dispose();
			System.exit (0);
		}
	}
}