java连接数据库，实现登录页面

1.倒入jar包，使用Driver
2.

package mySQL;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

public class 登录首页 {

	JFrame f;
	JLabel l1,l2,lv,l,lc,lt;
	JTextField t1,tv;
	JPasswordField t2;
	JButton b1,b2,b3;
	JPanel p1,p2,p3,p;
	BufferedImage image;
	String scode="";
	void init() {
		f=new JFrame("登录窗口");
		l1=new JLabel("学    号",JLabel.RIGHT);
        lv=new JLabel("验证码");
        lt=new JLabel("用户登录",JLabel.CENTER);
        lt.setFont(new Font("宋体",Font.BOLD,18));
        image=getImage();
        l=new JLabel(new ImageIcon(image));
		l2=new JLabel("姓    名",JLabel.RIGHT);
		t1=new JTextField(10);
		tv=new JTextField(10);
		t2=new JPasswordField(10);
		b1=new JButton("确定");
		b2=new JButton("取消");
		b3=new JButton("新用户注册");
		MyListener ll=new MyListener();
		b1.addActionListener(ll);
		b2.addActionListener(ll);
		b3.addActionListener(ll);
		p1=new JPanel(new FlowLayout(FlowLayout.LEFT));
		p2=new JPanel(new FlowLayout(FlowLayout.LEFT));
		p3=new JPanel();
		p=new JPanel(new FlowLayout(FlowLayout.LEFT));
		p1.add(l1);
		p1.add(t1);
		p2.add(l2);
		p2.add(t2);
		p3.add(b1);
		p3.add(b2);
		p3.add(b3);
		p.add(lv);
		p.add(tv);
		p.add(l);
		lc=new JLabel("看不清，换一张");
		lc.setFont(new Font("宋体", Font.ITALIC, 10));
		lc.addMouseListener(new MouseAdapter() {
			public void mouseClicked(MouseEvent arg0) {
				super.mouseClicked(arg0);
				image=getImage();
				l.setIcon(new ImageIcon(image));
			}
			public void mouseEntered(MouseEvent arg0) {
				super.mouseEntered(arg0);
				lc.setForeground(Color.green);
			}
		});
		p.add(lc);
		f.setLayout(new GridLayout(5,1));
		f.add(lt);
		f.add(p1);
		f.add(p2);
		f.add(p);
		f.add(p3);
		f.setSize(400,300);
		Dimension dim=Toolkit.getDefaultToolkit().getScreenSize();
		int x=(int)((dim.getWidth()-f.getWidth())/2);
		int y=(int)((dim.getHeight()-f.getHeight())/2);
		f.setLocation(x, y);
		f.setVisible(true);
		f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}
	BufferedImage getImage() {
		image=new BufferedImage(60, 20,BufferedImage.TYPE_INT_RGB);
		Graphics g=image.getGraphics();
		g.setColor(Color.white);
		g.fillRect(0, 0, 60, 20);
		g.setColor(Color.red);
		g.setFont(new Font("宋体", Font.BOLD, 15));
		String st="";
		for(int i=0;i<4;i++) {
			int x=(int)(Math.random()*10);
			st=String.valueOf(x);
			scode+=st;
			g.drawString(st, 15*i+5, 12);
		}
		for(int i=0;i<100;i++) {
			g.setColor(new Color(50+(int)(Math.random()*100), 50+(int)(Math.random()*100), 50+(int)(Math.random()*100)));
			g.drawOval((int)(Math.random()*60), (int)(Math.random()*20), 1, 1);
		}
		return image;
	}
	class MyListener implements ActionListener {
			 public void actionPerformed(ActionEvent e) {
			 	if(e.getSource()==b1) {
					 String uName=t1.getText(); //用户输入的用户名
			    	char s[]=t2.getPassword();
			    	String uPass=String.valueOf(s); //用户输入的密码
			    	String ucode = tv.getText();//用户输入的验证码
			    	System.out.println("输入的用户名"+uName+",密码："+uPass+"，验证码:"+ucode+",下面开始验证。。。");
			    	/*登录控制：
			    	 * 1.判断验证码
			    	 *    	验证码正确
			    	 *    		验证用户名
			    	 *    		验证密码
			    	 *    验证码错误：提示
			    	*/
			    	if(ucode.equals(scode)) {
			    		
			    	}else {
			    		JOptionPane.showMessageDialog(null,"验证失败");
			    	}
			    	Connection con = null;
					Statement st= null;
					ResultSet rs= null;
					try {
						Class.forName("com.mysql.jdbc.Driver");
						String url="jdbc:mysql://127.0.0.1:3306/gradem";
						con = DriverManager.getConnection(url, "root", "001201");
						st = con.createStatement();
						String sql = "select * from student where sno='"+uName+"'and sname='"+uPass+"'";
						rs = st.executeQuery(sql);
						System.out.println(sql);
						if(rs.next()) {
							//System.out.println(rs.getRow()+":"+uName+"\t"+uPass);
							JOptionPane.showMessageDialog(f,"登录成功");
						}else {
							JOptionPane.showMessageDialog(f,"登录失败");
						}
					} catch (ClassNotFoundException e1) {
						// TODO Auto-generated catch block
						e1.printStackTrace();
					} catch (SQLException e1) {
						// TODO Auto-generated catch block
						e1.printStackTrace();
					}finally {
						if(rs!=null)
							try {
								rs.close();
							} catch (SQLException e1) {
								e1.printStackTrace();
							}
						if(st!=null)
							try {
								st.close();
							} catch (SQLException e1) {
								e1.printStackTrace();
							}
						if(con!=null)
							try {
								con.close();
							} catch (SQLException e1) {
								e1.printStackTrace();
							}
					}
				
			 	}
			 	else if(e.getSource()==b3) {
			 		f.dispose();
			 		new 用户注册().init();
			 	}
			 		
			 	else System.exit(0);
	    	
	    }
	}
   
    public static void main(String args[]) {
    	登录首页 l=new 登录首页();
    	l.init();
    }
    

}

本文地址：https://blog.csdn.net/m0_46641784/article/details/112005609