xuanke.java

自己用java编的选课系统

package xuankexitong;
import java.awt.*;

import javax.swing.*;

import java.awt.event.*;
import java.sql.*;
import java.lang.*;
import javax.swing.event.*;
import java.io.*;
import java.util.*;
import java.net.*;
import javax.swing.table.*;
public class Xuanke extends JFrame implements ActionListener{
String name="",password="",right="";
JTextField t1;
JPasswordField t2;
JRadioButton rb1, rb2, rb3;
JButton button;
ButtonGroup bg=new ButtonGroup();
Connection con;
Statement stmt;
ResultSet res=null;
int count=0;
public Xuanke(){
	addConnection();
	  setTitle("选课查询系统");
	  addWindowListener(new WindowAdapter(){
		  public void windowClosing(WindowEvent e){
			  System.exit(0);
		  }
	  });
	  Container content=getContentPane();
	  content.setLayout(new BorderLayout());
	  JPanel p1=new JPanel(),p2=new JPanel(),p3=new JPanel(),p4=new JPanel(),p5=new JPanel();
	  p5.setLayout(new GridLayout(4,1));
	  JLabel l1=new JLabel("用户名"),l2=new JLabel("口   令");
	   t1=new JTextField(20);
	   t2=new JPasswordField(20);
	  button=new JButton("确定");
	  button.addActionListener(this);
	  p4.add(button);
	  rb1=new JRadioButton("管理员");
	  rb1.addActionListener(this);
	  bg.add(rb1);
	  rb2=new JRadioButton("教师");
	  rb2.addActionListener(this);
	  bg.add(rb2);
	  rb3=new JRadioButton("学生");
	  rb3.addActionListener(this);
	  bg.add(rb3);
	  p1.add(l1);
	  p1.add(t1);
	  p2.add(l2);
	  p2.add(t2);
	  p3.add(rb1);
	  p3.add(rb2);
	  p3.add(rb3);
	  p5.add(p3);
	  p5.add(p1);
	  p5.add(p2);
	  p5.add(p4);
	 content.add(p5,BorderLayout.CENTER);
	 Toolkit   tk=getToolkit();   
	  Dimension   screenSize=tk.getScreenSize();  
	  int   frameWidth=400;   
	  int   frameHeight=250;   
	  setBounds((screenSize.width-frameWidth)/2,(screenSize.height-frameHeight)/2,frameWidth,frameHeight);   
  setVisible(true);
}
	public void actionPerformed(ActionEvent e){
		String c=e.getActionCommand();
		if(c.equals("管理员")){
			right=c;
		}else if(c.equals("教师")){
			right=c;
		}else if(c.equals("学生")){
			right=c;
		}else if(c.equals("确定")){
			if(right.equals(""))
				JOptionPane.showMessageDialog(null,"请选择身份");
			else{
				if(count==3&&right.equals("管理员")){
					JOptionPane.showMessageDialog(null,"错误次数超过三次，不能取得管理员权限");
				}
				else{
				String string=null;
				String s1=t1.getText(),s2=t2.getText();
				String sql="SELECT password FROM user WHERE username='"+s1+"' AND right='"+right+"'";
				try{
				res=stmt.executeQuery(sql);
  				while(res.next()){
  					string=res.getString("password");
  				}
  				if(string==null||!string.equals(s2)){
  					JOptionPane.showMessageDialog(null,"用户名或密码错误，请重新输入");
  					if(right.equals("管理员"))
  						count++;
  				}
  				else if(string.equals(s2))
  					xinjian(right,s1);
				}
				catch(SQLException se){
		 			  se.printStackTrace(System.out);
		 			 }
			}
			}
		}
	}
	public void xinjian(String right,String username){
		if(right.equals("教师"))
			new Teacher(username);
		if(right.equals("学生"))
			new Student(username);
		if(right.equals("管理员"))
			new Administrator(username);
	}
	public void addConnection(){
		 try{
 			  Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
 			 }
 			 catch(ClassNotFoundException g){
 				 JOptionPane.showMessageDialog(null,"驱动器加载失败，无法建立数据库连接");
 			  return;
 			 }
 			 try{
 				   con=DriverManager.getConnection("jdbc:odbc:stu","","");
 			 stmt=con.createStatement();
 				 }
 			 catch(SQLException se){
 			  se.printStackTrace(System.out);
 			 }
	}
	public static void main(String[] args){
		Xuanke xuanke=new Xuanke();
	}
}