logindia.java

使用java连接server sql 2000 的一个小作业

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


public class LoginDia extends JDialog implements ActionListener
{
      JPanel p1=new JPanel();
      JPanel p2=new JPanel();
      JPanel p3=new JPanel();
      JPanel p4=new JPanel();
      JPanel p5=new JPanel();
    JTextField UserNameText=new JTextField(15);
    JPasswordField PassWordText=new JPasswordField(15);
    JButton ok=new JButton("学生登录"); 
    JButton cancel=new JButton("取消");
    JButton register=new JButton("注册");
    JButton teacherLogin=new JButton("老师登录");
    /////////////////////////
    String sql; 
    Connection conn; 
    Statement stmt; 
    ResultSet rs; 
    //////
    String ID=new String();
 
    public LoginDia()
    {
        setModal(true);
       
        
        Container contentPane=this.getContentPane();
        contentPane.setLayout(new GridLayout(5,1));
   
        p2.add(new JLabel("用户名："));p2.add(UserNameText);
        p3.add(new JLabel("密   码："));p3.add(PassWordText);
        p4.add(teacherLogin);p4.add(ok);p4.add(register);p4.add(cancel);
       ////////////////////
        ok.addActionListener(this);      
        cancel.addActionListener(this);
        register.addActionListener(this);
        UserNameText.addActionListener(this);
        PassWordText.addActionListener(this);
        teacherLogin.addActionListener(this);
       
        contentPane.add(p1);
        contentPane.add(p2);
        contentPane.add(p3);
        contentPane.add(p4);
        contentPane.add(p5);
        //////////////////////////
        Color c=new Color(241,250,255);
        p1.setBackground(c);
        p2.setBackground(c);
        p3.setBackground(c);
        p4.setBackground(c);
        p5.setBackground(c);
        
        //////////////////////////////////////
        setDefaultCloseOperation(JDialog.EXIT_ON_CLOSE);
        setSize(400,300);
        Dimension screen=Toolkit.getDefaultToolkit().getScreenSize();
        setLocation((screen.width-400)/2,(screen.height-300)/2);
        setTitle("登录窗口");
        setResizable(false);
        setVisible(true);    
    }
    public void actionPerformed(ActionEvent e){
        if(e.getSource()==ok||e.getSource()==PassWordText){
            try{
               Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); 
               String url="jdbc:odbc:SUMMIT"; 
               String user="sa"; 
               String password="198662"; 
               conn= DriverManager.getConnection(url,user,password);
               stmt=conn.createStatement(); 
               String tem=UserNameText.getText().trim();
               ID=tem;
               sql="select SPASSWD from Student where SNO="; 
               sql=sql+"'"+tem+"'";
              
         
               rs=stmt.executeQuery(sql); 
               rs.next();

        //////登录成功
            if(rs.getString(1).trim().equals((String)PassWordText.getText().trim()))
               {
                  
                   rs.close(); 
                   stmt.close();
                   conn.close(); 
                   dispose();
                 
                  StudentFrame studentFrame=new StudentFrame(ID); 
            }
            else{
                   //////////登录失败
                JOptionPane.showMessageDialog(null,"用户名或密码错误！");
                UserNameText.requestFocus();
                UserNameText.setSelectionStart(0);
                UserNameText.setSelectionEnd(UserNameText.getText().length());   }
        }catch(Exception ee){ JOptionPane.showMessageDialog(null,"用户名不存在或"+" 连接数据库错误"); }
        }
        /////////////注册
        if(e.getSource()==register){
            try{ RegisterDia register=new RegisterDia();
                  UserNameText.setText("");
                 PassWordText.setText("");
                 UserNameText.requestFocus();}
                  catch(Exception eee){JOptionPane.showMessageDialog(null,eee.getMessage()+"  开启注册窗口错误");}
               }
        
        if(e.getSource()==cancel){
            System.exit(0);
        } 
        if(e.getSource()==UserNameText){
            PassWordText.requestFocus();}
       if(e.getSource()==teacherLogin){
    	   try{
               Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); 
               String url="jdbc:odbc:SUMMIT"; 
               String user="sa"; 
               String password="198662"; 
               conn= DriverManager.getConnection(url,user,password);
               stmt=conn.createStatement(); 
               String tem=UserNameText.getText().trim();
               sql="select * from Teacher where ID="; 
               sql=sql+"'"+tem+"'";
               rs=stmt.executeQuery(sql); 
               rs.next();
               if(rs.getString(2).trim().equals(PassWordText.getText().toString().trim()))
               {   conn.close();
                  stmt.close();
                  dispose(); 
                  new TeacherFrame();
                 }
               else{
            	   JOptionPane.showMessageDialog(null, "登录失败");
            	   PassWordText.setText("");
            	   UserNameText.setText("");
            	   UserNameText.requestFocus();
               }
       }catch(Exception e2){JOptionPane.showMessageDialog(null, "登录失败");}
       }
   
}
}