login.java

java语言实现的一个简单学生管理系统

package app.login;
import app.sa.*;
import app.guest.*;
import java.sql.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
public class Login extends JFrame implements ActionListener,ItemListener
{private JButton yes,no; 
 private String []name={"访客","管理员"};
 private JComboBox comboBox=new JComboBox(name);
 private JTextField nameField;
 private String pwd="";
 private int ss,s1=111,s2=110,s3=100;
 
 private JPasswordField pwdField;
 public Login()
 {  setTitle("请选择访问方式");
    Toolkit tk=Toolkit.getDefaultToolkit();
    Image img=tk.getImage("images/Eagle.jpg");
    setIconImage(img);
     setSize(300, 200);
     setLocation(200,180);
     setResizable(false);
     this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
 Container contentPane=getContentPane();
 GridBagLayout gbl=new GridBagLayout();
 contentPane.setLayout(gbl);
 yes=new JButton("确定");
 no=new JButton("退出");
 comboBox.addItemListener(this);
 JLabel title   = new JLabel("学生数据管理系统");
 JLabel name    = new JLabel("用户名");
  nameField=new JTextField("guest",10);
  pwdField=new JPasswordField(10);
 JLabel password = new JLabel("密码");
 JLabel payment = new JLabel("登录方式");

 pwdField.setText("123456"); 
      
      
 title.setFont(new Font("Times-Roman", 
                               Font.BOLD + Font.ITALIC,
                               16));
                               
 GridBagConstraints gbc=new GridBagConstraints();
 gbc.anchor = GridBagConstraints.CENTER;
 gbc.weightx = 100;
 gbc.weighty = 100;
 add(title,gbc,0,0,3,1);
 gbc.anchor = GridBagConstraints.CENTER;

 add(name,gbc,0,2,1,2);
 add(password,gbc,0,4,1,2);
 gbc.anchor = GridBagConstraints.WEST;
 add(nameField,gbc,2,2,1,2);
 add(pwdField,gbc,2,4,1,2);
 gbc.anchor = GridBagConstraints.CENTER;
 add(payment,gbc,0,6,1,2);
 gbc.anchor = GridBagConstraints.WEST;
 add(comboBox,gbc,2,6,1,2);
 gbc.anchor = GridBagConstraints.EAST;
 add(yes,gbc,0,8,1,2);
 gbc.anchor = GridBagConstraints.CENTER;
 add(no,gbc,2,8,1,2);
 
 yes.addActionListener(this);
 no.addActionListener(this);

}
public void add(Component c,GridBagConstraints gbc,
                int x,int y,int w,int h)
 { gbc.gridx=x;
   gbc.gridy=y;
   gbc.gridwidth=w;
   gbc.gridheight=h;
   getContentPane().add(c,gbc);
  }
public void actionPerformed(ActionEvent evt)
 {
  Object source=evt.getSource();
  
  if(source==yes)
  {
  try
      {
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
      }
    catch (ClassNotFoundException e)
      {
      System.out.println(e.getMessage());
      }
    try
      {
      Connection con =
        DriverManager.getConnection("jdbc:odbc:student");
      Statement stmt = con.createStatement();
      String s=nameField.getText();
      pwd=new String(pwdField.getPassword());
      
      ResultSet rs =
      
        stmt.executeQuery("select * from pwdTab where 用户名='"+s+"' and 密码='"+pwd+"' "); 


      if (rs.next())
        {
           ss=rs.getInt("权限") ;
            if (ss==s1)     //管理员
           {dispose();
             JFrame saFrame = new sa();
             saFrame.show();}
           if (ss==s2)      //注册
             {dispose();
             JFrame logFrame = new sa();
             logFrame.show();}
           if(ss==s3)       //访客
           {dispose();
          
            JFrame guestframe = new guest();
            guestframe.show();
           	}
                        
       }
       else JOptionPane.showMessageDialog(this,"用户名与密码不符","请检查,有个小错误",
                                  JOptionPane.WARNING_MESSAGE);
      stmt.close();
      con.close();
      }
    catch (SQLException ex)
      {
      System.err.println("SQLException: " + ex.getMessage());
     }
   
     
  }
  else if(source==no)
  {System.exit(0);
   
  }
 }
public void itemStateChanged(ItemEvent evt)
 { int i=(int)comboBox.getSelectedIndex();
   if (i==0)
   {nameField.setText("访客");
    pwdField.setText("guest");
   }
   else {
   	nameField.setText("");
   	pwdField.setText("");
   	}
 }
public static void main(String[] args)
 {Frame f=new Login();
 
  f.show();
  
   } 
 }