15周

package com.login;

import java.sql.*;
import java.util.Scanner;

public class login {

    
    public static void main(String[] args) {
        
            Connection con=null;
            Statement st=null;
            ResultSet rs=null;
            Scanner sc=new Scanner(System.in);
            System.out.println("请输入用户名");
            String username=sc.next();
            System.out.println("请输入密码");
            String password=sc.next();
            String sql="select * from student where username='"+username+"'and password='"+password+"'";
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url="jdbc:mysql://localhost:3306/student";

                con=DriverManager.getConnection(url,
                        "root","0000");
                st=con.createStatement();
                rs=st.executeQuery(sql);
                if(username.equalsIgnoreCase(username)&&password.equalsIgnoreCase(password)){
                    System.out.println("success");
                }else{
                    System.out.println("fail");

                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
         catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

 题目2：在上一题基础上，当登录成功后，将t_user表（id、name、sex、birthday）的信息进行显示（要求使用DB.java完成登录和获取t_user表中数据的操作），最后再对t_user表进行一条记录的添加操作。

package com.login;

import java.sql.*;
import java.util.Scanner;

public class usermodify {

    
    public static void main(String[] args) {
        
            Connection con=null;
            Statement st=null;
            boolean rs;
            ResultSet rt=null;
            Scanner sc=new Scanner(System.in);
            System.out.println("请输入用户名");
            String username=sc.next();
            System.out.println("请输入密码");
            String password=sc.next();
            String sql="select * from login where username='"+username+"'and password='"+password+"'";
        try {
            Class.forName("com.mysql.jdbc.Driver");
            String url="jdbc:mysql://localhost:3306/dbfjd";
                con=DriverManager.getConnection(url,
                        "root","0000");
                st=con.createStatement();
                rs=st.execute(sql);
                if(username.equalsIgnoreCase(username)&&password.equalsIgnoreCase(password)){
                    System.out.println("登陆成功");
                    rt=DB.getInstance().executeSelect("select * from user", args);            
                while(rt.next()){    
                    System.out.println("生日"+rt.getString(2)+"性别"+rt.getString(3)+"姓名"+rt.getString(4));    
                    
                }
                System.out.println("请输入生日");
                String birthday=sc.next();
                System.out.println("请输性别");
                String sex=sc.next();
                System.out.println("请输入姓名");
                String name=sc.next();
                String sql1="insert into user (birthday,sex,name)values('"+birthday+"','"+sex+"','"+name+"')";

                int i=DB.getInstance().executeModify(sql1, args);
                if(i>0){
                    System.out.println("插入成功");

                }else{
                    System.out.println("插入失败");

                }
                }else{
                    System.out.println("登陆失败");

                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
         catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}