land.java

实现学生信息管理,使学生信息管理工作更加容易,从而提高工作效率,降低管理成本.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
 
public class Land extends JFrame 
{
	JFrame jf;
	JTextField textname=new JTextField();
	JPasswordField textmima=new JPasswordField();
	//JLabel label= new JLabel("学生信息管理系统");
	JLabel labelname=new JLabel("用户名");
	JLabel labelmima=new JLabel("密码");
	
	JButton btenter=new JButton("确定");
	JButton btcancel=new JButton("清空");
	
	public Land()
	 {
	  jf=this;
	  setTitle("登陆");
	  Font f=new Font("新宋体",Font.PLAIN,12);
	  Container ctn=getContentPane();
	  ctn.setLayout(null);
	  
	  labelname.setBounds(45,40,55,20);
		labelname.setFont(f);
		ctn.add(labelname);
		textname.setBounds(95,40,120,20);
		ctn.add(textname);
		
	  labelmima.setBounds(45,70,45,20);
		ctn.add(labelmima);
		labelmima.setFont(f);
     	textmima.setBounds(95,70,120,20);
		ctn.add(textmima);
		
		btenter.setBounds(90,110,60,20);
		btenter.setFont(f);
		ctn.add(btenter);
		Monitor_1 bt=new Monitor_1();
		btenter.addActionListener(bt);

		btcancel.setBounds(155,110,60,20);
		btcancel.setFont(f);
		ctn.add(btcancel);
		Monitor_2 btc=new Monitor_2();
		btcancel.addActionListener(btc);
		jf.setResizable(false);
		jf.setLocation(400, 400);
		jf.setSize(300,200);
		jf.setVisible(true);
	
	    	
	}
	
	class Monitor_1 implements ActionListener {
 	public void actionPerformed (ActionEvent e){
     if(textname.getText().equals("")){
					new JOptionPane().showMessageDialog(null,"用户名不能为空!");
					}
				else if(textmima.getText().equals("")){
					new JOptionPane().showMessageDialog(null,"密码不能为空!");
					}
				else{
					String sql="select * from user where user_id = '" + textname.getText() + "' and password = '" + textmima.getText()+ "'";
					System.out.println(sql);
					Judge(sql);
					}
	}
 }

    class Monitor_2 implements ActionListener{
    public void actionPerformed(ActionEvent e){
   	textname.setText("");
   	textmima.setText("");
   	
   	}	
 }

 private void Judge(String sqlString) {

    if (database.joinDB()) {
      if (database.query(sqlString))
         try{
           if(database.rs.isBeforeFirst()) {
             System.out.println("密码正确");
             jf.setVisible(false);
             //关闭数据库连接
             database.cn.close();
             new Main();
           }
           else {
             System.out.println("错误");
             new JOptionPane().showMessageDialog(null,"用户名或密码错误!","",JOptionPane.ERROR_MESSAGE);
            }
          }catch(Exception ex) {
             System.out.println(ex.getMessage());
          }
    }
    else{
   	System.out.println("连接数据库不成功!!!");
   	}
  }
	public static void main(String args[]){
		new Land();
		}
}