学生成绩查询.java

利用数据库做了一个小小的学生考试成绩查询管理系统

package classfile;

import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;
public class Login extends JFrame implements ActionListener
{
	/**登陆程序
	 * 
	 */
	private static final long serialVersionUID = 1L;
	JLabel lab1=new JLabel("欢迎您到网上成绩查询系统！");
	JLabel lab2=new JLabel("用户名：");
	JLabel lab3=new JLabel("密码：");
	JTextField txt1=new JTextField(20);
	JPasswordField txt2=new JPasswordField(20);
	JButton btn1=new JButton("学生入口");
	JButton btn2=new JButton("教师入口");
	JButton btn3=new JButton("管理员入口");
	JPanel p=new JPanel();
	JPanel p1=new JPanel();
	JPanel p2=new JPanel();
	static String name;
	static String name1;
	public Login()
	{
		txt1.setBackground(Color.cyan);
		txt2.setBackground(Color.cyan);
		p.setLayout(new GridLayout(2,2));
		p.add(lab2);
		p.add(txt1);
		p.add(lab3);
		p.add(txt2);
		p.setBackground(Color.pink);
		p2.setLayout(new GridLayout(1,3));
		p2.add(btn1);
		p2.add(btn2);
		p2.add(btn3);
		p1.setLayout(new BorderLayout());
		p1.add(lab1,BorderLayout.NORTH);
		p1.add(p,BorderLayout.CENTER);
		p1.add(p2,BorderLayout.SOUTH);
		this.getContentPane().add(p1,BorderLayout.CENTER);
		this.setBounds(100,100,400,200);
		this.setVisible(true);
		btn1.addActionListener(new Listener1());
		btn2.addActionListener(this);
		btn3.addActionListener(new Listener2());	
	}
	class Listener1 implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			if((txt1.getText()==" ")||(txt2.getText()==" "))
			{
				JOptionPane.showMessageDialog(null,"用户名或密码不能为空！");
			}
			else
			{
				name=txt1.getText().trim();
				String pw=txt2.getText().trim();
				String sql="select count(*) from Login_stu where user_name='"+name+"'and upassword='"+pw+"'";
				try
				{
					dataBase db=new dataBase();
					ResultSet rs=db.getResult(sql);
					while(rs.next())
					{
						int count=rs.getInt(1);
						if(count==1)
						{
							Student_user st=new Student_user();
							sql="select name from student where sno='"+name+"'";
							rs=db.getResult(sql);
							rs.next();
							name1=rs.getString(1);
						}
						else
						{
							JOptionPane.showMessageDialog(null,"该用户不存在或密码错误！");
						}
					}
					
				}
				catch(Exception ee)
				{
					ee.printStackTrace();
				}
			}
		}
	}
	class Listener2 implements ActionListener
	{
		public void actionPerformed(ActionEvent e)
		{
			if((txt1.getText()==" ")||(txt2.getText()==" "))
			{
				JOptionPane.showMessageDialog(null,"用户名或密码不能为空！");
			}
			else
			{
				name=txt1.getText();
				String pw=txt2.getText();
				String sql="select count(*) from Login_man where user_name='"+name+"'and upassword='"+pw+"'";
				try
				{
					dataBase db=new dataBase();
					ResultSet rs=db.getResult(sql);
					while(rs.next())
					{
						int count=rs.getInt(1);
						if(count==1)
						{
							Manager_user m=new Manager_user();
						}
						else
						{
							JOptionPane.showMessageDialog(null,"该用户不存在或密码错误！");
						}
					}
				}
				catch(Exception ee)
				{
					ee.printStackTrace();
				}
			}
		}
	}
	public void actionPerformed(ActionEvent e)
	{
		if((txt1.getText()==" ")||(txt2.getText()==" "))
			{
				JOptionPane.showMessageDialog(null,"用户名或密码不能为空！");
			}
			else
			{
				name=txt1.getText();
				String pw=txt2.getText();
				String sql="select count(*) from Login_tea where user_name='"+name+"'and upassword='"+pw+"'";
				dataBase db=new dataBase();
				ResultSet rs=db.getResult(sql);
				try
				{
					
					while(rs.next())
					{
						int count=rs.getInt(1);
						if(count==1)
						{
							Teacher_user t=new Teacher_user();
							t.setVisible(true);
						}
						else
						{
							JOptionPane.showMessageDialog(null,"该用户不存在或密码错误！");
						}
					}
				}
				catch(Exception ee)
				{
					ee.printStackTrace();
				}
			}
	}
	public static void main(String args[])
	{
		new Login();
	}
}



class dataBase
{	
	Connection con;
	public dataBase()
	{
		try 
	  	{
			Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
       		con = DriverManager.getConnection( "jdbc:odbc:stu", "system", "haohao");
        	
        	} 
     		catch(Exception ex) 
     		{
         		System.err.println("SQLException: " + ex.getMessage());
         		ex.printStackTrace();
         	
     		}      
	}
	public ResultSet getResult(String sql)
	{
		try 
	  	{
	  		Statement stmt = con.createStatement(); 
         	ResultSet rs=stmt.executeQuery(sql);
         	return rs;
          
     	} 
     	catch(Exception ex) 
     	{
         	System.err.println("SQLException: " + ex.getMessage());
         	ex.printStackTrace();
         	return null;
     	}      			
	}
	public boolean executeSql(String sql)
	{
		try 
	  	{
	  		Statement stmt = con.createStatement(); 
         	stmt.executeUpdate(sql);
         	return true;
          
     	} 
     	catch(Exception ex) 
     	{
         	System.err.println("SQLException: " + ex.getMessage());
         	ex.printStackTrace();
         	return false;
     	}      
	}
}