mainframe.java

用JAVA实现的小的学生管理系统.JAVA与数据库的结合使用.

// MainFrame.java - Chapter 16 version.

// Copyright 2000 by Jacquie Barker - all rights reserved.

// A GUI class.


import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.util.*;

public class MainFrame extends JFrame {
	// Define all of the components here as attributes of this class.

	private JPanel leftPanel;
	private JPanel topLeftPanel;
	private JPanel labelPanel;
	private JPanel fieldPanel;
	private JPanel bottomLeftPanel;
	private JPanel rightPanel;
	private JPanel buttonPanel;
	private JTextField ssnField;
	private JTextField nameField;
	private JLabel totalCoursesLabel;
	private JButton dropButton;
	private JButton addButton;
	private JButton logoffButton;
	private JButton saveScheduleButton;
	private JLabel l1;
	private JLabel l2;
	private JLabel l3;
	private JLabel l4;
	private JList studentCourseList;
	private JList scheduleOfClassesList;

	// Maintain a handle on the Student who is logged in.
	// (Whenever this is set to null, nobody is officially logged on.)

	private Student currentUser;

	// Constructor.

	public MainFrame() {
		// Initialize attributes.

		currentUser = null;
	    String plaf = "";

		// Note that using "this." as a prefix is unnecessary -
		// any method calls that stand alone (without a dot notation
		// prefix) are UNDERSTOOD to be invoked on THIS object.

		this.setTitle("学生注册系统");
		this.setSize(600, 350);
		Container contentPane = this.getContentPane( );
		
        // Set the style of the interface
		plaf = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
    	try{
    		
    		UIManager.setLookAndFeel(plaf);
    		SwingUtilities.updateComponentTreeUI(this);
    		}	catch(Exception e){}
		// Technique for centering a frame on the screen.
		
	

		Dimension frameSize = this.getSize();
		Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
		this.setLocation((screenSize.width - frameSize.width)/2,
		                 (screenSize.height - frameSize.height)/2);

		// Create a few panels.

		leftPanel = new JPanel();
		leftPanel.setLayout(new GridLayout(2, 1));

		topLeftPanel = new JPanel();
		topLeftPanel.setLayout(new GridLayout(1, 2));

		labelPanel = new JPanel();
		labelPanel.setLayout(new GridLayout(4, 1));

		fieldPanel = new JPanel();
		fieldPanel.setLayout(new GridLayout(4, 1));

		bottomLeftPanel = new JPanel();
		bottomLeftPanel.setLayout(new BorderLayout());

		rightPanel = new JPanel();
		rightPanel.setLayout(new BorderLayout());

		buttonPanel = new JPanel();
		buttonPanel.setLayout(new GridLayout(1, 4));

		// We'll allow the main frame's layout to remain the
		// default BorderLayout.

		// Note that we are adding labels without maintaining
		// handles on them!

		JLabel l = new JLabel("学号:  ");
		l.setForeground(Color.black);
 		labelPanel.add(l);
		l = new JLabel("姓名:  ");
		l.setForeground(Color.black);
 		labelPanel.add(l);
		l = new JLabel("课程总汇:  ");
		l.setForeground(Color.black);
		labelPanel.add(l);

		// Add an empty label for padding/white space.

		l = new JLabel("");
 		labelPanel.add(l);

		// We DO maintain handles on the text fields, however, so
		// that we can later go back and read their contents
		// by name.  Note our choice of descriptive names for these.

 		ssnField = new JTextField(10);
 		nameField = new JTextField(10);

		// Because this next field is not editable, we are making it
		// a JLabel.  (I could have also made it a non-editable
		// JTextField, but I wanted it to look like a label ...)

		totalCoursesLabel = new JLabel();
		totalCoursesLabel.setForeground(Color.lightGray);
		fieldPanel.add(ssnField);
		fieldPanel.add(nameField);
		fieldPanel.add(totalCoursesLabel);

		// Add an empty label for padding/white space.

		l = new JLabel("");
 		fieldPanel.add(l);

		// Create the buttons and add them to their panel.  Again,
		// note use of descriptive names.

		dropButton = new JButton("弃选");
		addButton = new JButton("添加");
		logoffButton = new JButton("登出");

		// Technique for creating a multi-line button label.

		saveScheduleButton = new JButton();
		saveScheduleButton.setLayout(new GridLayout(2, 1));
		l1 = new JLabel("保存我的", JLabel.CENTER);
		l1.setForeground(Color.black);
		l2 = new JLabel("课程表！", JLabel.CENTER);
		l2.setForeground(Color.black);
		saveScheduleButton.add(l1);
		saveScheduleButton.add(l2);

		buttonPanel.add(dropButton);
		buttonPanel.add(saveScheduleButton);
		buttonPanel.add(new JLabel("")); // white space padding
		buttonPanel.add(addButton);
		buttonPanel.add(logoffButton);

		studentCourseList = new JList();
		studentCourseList.setFixedCellWidth(200);
		bottomLeftPanel.add(studentCourseList, BorderLayout.CENTER);

		l = new JLabel("已选课程:");
		l.setForeground(Color.black);
		bottomLeftPanel.add(l, BorderLayout.NORTH);

		l = new JLabel("--- 课程表 ---", JLabel.CENTER);
		l.setForeground(Color.black);
		rightPanel.add(l, BorderLayout.NORTH);

		scheduleOfClassesList = new JList(SRS.scheduleOfClasses.
						  getSortedSections());
		scheduleOfClassesList.setFixedCellWidth(250);
		rightPanel.add(scheduleOfClassesList, BorderLayout.EAST);

		// Initialize the buttons to their proper enabled/disabled
		// state.

		resetButtons();

		// Finally, attach all of the panels to one another
		// and to the frame.
 		// Add in ascending row, then column, order.

		topLeftPanel.add(labelPanel);
		topLeftPanel.add(fieldPanel);
		leftPanel.add(topLeftPanel);
		leftPanel.add(bottomLeftPanel);
 		contentPane.add(leftPanel, BorderLayout.WEST);
 		contentPane.add(rightPanel, BorderLayout.CENTER);
 		contentPane.add(buttonPanel, BorderLayout.SOUTH);

		// ------------------
		// Add all behaviors.
		// ------------------

		// Different types of components require different types
		// of listeners:
		//
		// o	Text fields respond to an ActionListener
		//	whenever the Enter key is pressed.
		//
		// o	Buttons respond to an ActionListener
		// 	whenever the button is clicked.
		//
		// o	JLists respond to a ListSelectionListener
		//	whenever an item is selected.

		ActionListener aListener;
		ListSelectionListener lListener;
		WindowAdapter wListener;

		// ssnField

		aListener = new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				// First, clear the fields reflecting the
				// previous student's information.
				clearFields();

				// We'll try to construct a Student based on
				// the ssn we read, and if a file containing
				// Student's information cannot be found,
				// we have a problem.
				String id = ssnField.getText();
				Student theStudent = new Student(id);
				if (!theStudent.successfullyInitialized()) {
				    // Drat!  The ID was invalid.
				    currentUser = null;
                    ssnField.setText("");
				    // Let the user know that login failed,
				    // UNLESS the ID typed was blank,
				    // signalling a successful log-off.
				    JOptionPane.showMessageDialog(null,
					//"Invalid student ID; please try again.",
					"学号非法，请重试！",
					"Invalid Student ID",
					JOptionPane.WARNING_MESSAGE);
				}
				else {
				    // Hooray!  We found one!  Now, we need
				    // to request and validate the password.
				    PasswordPopup pp = new PasswordPopup(
							   MainFrame.this);
				    String pw = pp.getPassword();
				    pp.dispose();

				    if (theStudent.validatePassword(pw)) {
					    currentUser = theStudent;
					    setFields(theStudent);

					    // Let the user know that the
					    // login succeeded.
					    JOptionPane.showMessageDialog(null,
						
						theStudent.getName()+"登录成功！"  + ".",
						"Log In Succeeded",
						JOptionPane.INFORMATION_MESSAGE);
				    }
				    else {
					    // Password validation failed;
					    // notify the user of this.
					    JOptionPane.showMessageDialog(null,
						"密码错误！ " +
						"请重试!",
						"Invalid Password",
						JOptionPane.WARNING_MESSAGE);
				    }
				}

				MainFrame.this.repaint();

				// Check states of the various buttons.
				resetButtons();
			}
		};
		ssnField.addActionListener(aListener);

		// addButton

		aListener = new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				// Determine which section is selected
				// (note that we must cast it, as it
				// is returned as an Object reference).
				Section selected = (Section)
					scheduleOfClassesList.getSelectedValue();

				// Check to see if this COURSE is already
				// one that the student registered for,
				// even if the SECTION is different.
				// If so, warn them of this.
				if (currentUser.isCurrentlyEnrolledInSimilar(
					selected)) {
				      // Create a String array of TWO lines
				      // of messsage text, so that the popup
				      // window won't be too wide.
				      String[] message =
					{  "你已经选过本课程！",
					  " " };

				      // Then, we can just hand the String
				      // array in to the showMessageDialog()
				      // call.
				      JOptionPane.showMessageDialog(null,