数据库连接-登录

 1 public class Demo3 {
 2     public static void main(String[] args) throws SQLException, ClassNotFoundException {
 3         //1.注册驱动
 4         Class.forName("com.mysql.jdbc.Driver");
 5         //2.获取连接对象
 6         String url="jdbc:mysql://localhost:3306/day22_JDBC?characterEncoding=UTF-8";
 7         String username="root";
 8         String password="123456";
 9         Connection conn=DriverManager
10                         .getConnection(url,username,password);
11         //3.获取语句执行对象
12         Statement sta=conn.createStatement();
13         //让用户输入用户名和密码
14         Scanner sc=new Scanner(System.in);
15         System.out.println("请输入用户名");
16         String uname=sc.next();
17         System.out.println("请输入密码");
18         String pwd=sc.next();
19     
20         //4.执行sql
21         //用户信息写死
22         String sql="SELECT COUNT(*) FROM USER WHERE uname='"+uname+"' AND pwd='"+pwd+"'";
23         //
24         //
25         ResultSet rs=sta.executeQuery(sql);
26         //5.处理结果集
27         //
28         int count=0;
29         while(rs.next()){
30             count=rs.getInt(1);
31         }
32         if(count>0){
33             System.out.println("登陆成功~");
34         }
35         else{
36             System.out.println("登陆失败~");
37             
38         }
39         //6.释放资源
40         rs.close();
41         sta.close();
42         conn.close();
43     }
44 }

public class Demo3 {public static void main(String[] args) throws SQLException, ClassNotFoundException {//1.注册驱动Class.forName("com.mysql.jdbc.Driver");//2.获取连接对象String url="jdbc:mysql://localhost:3306/day22_JDBC?characterEncoding=UTF-8";String username="root";String password="123456";Connection conn=DriverManager.getConnection(url,username,password);//3.获取语句执行对象Statement sta=conn.createStatement();//让用户输入用户名和密码Scanner sc=new Scanner(System.in);System.out.println("请输入用户名");String uname=sc.next();System.out.println("请输入密码");String pwd=sc.next();//4.执行sql//用户信息写死String sql="SELECT COUNT(*) FROM USER WHERE uname='"+uname+"' AND pwd='"+pwd+"'";////ResultSet rs=sta.executeQuery(sql);//5.处理结果集//int count=0;while(rs.next()){count=rs.getInt(1);}if(count>0){System.out.println("登陆成功~");}else{System.out.println("登陆失败~");}//6.释放资源rs.close();sta.close();conn.close();}}