JDBC快速入门（四）

package com.byzhang.jdbc;
import com.byzhang.utils.JdbcUtils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;
public class JdbcDemo6 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入用户名:");
        String username = sc.nextLine();
        System.out.println("请输入密码:");
        String password = sc.nextLine();
        boolean flag = new JdbcDemo6().login(username, password);
        if(flag){
            System.out.println("登录成功！");
        }else{
            System.out.println("登录失败！");
        }
    }
    //登陆方法
    public boolean login(String userName, String password) {
        if(userName == null || password == null){
            return false;
        }
        Connection conn = null;
        Statement st = null;
        ResultSet res = null;
        try{
            conn = JdbcUtils.getConnection();
            String sql = "select * from user where username = '" +userName +"' and password = '"+password+"'";
            st = conn.createStatement();
            res = st.executeQuery(sql);
            return res.next();
        }catch (SQLException e){
            e.printStackTrace();
        }finally {
            JdbcUtils.close(res, st, conn);
        }
        return false;
    }
}