在没有使用PreparedStatement之前
SQL注入填写用户名:' or 1=1 or username='
一组合之后就变成:
select * from users where username=''or 1=1 or username='' and password=''
select * from users where true or false
select * from users where true
因为用的是if(rs.next())所以成功返回第一个用户
mysql -uroot -prootset character_set_client=gb2312;
set character_set_results=gb2312;
create database day14_user character set utf8 collate utf8_general_ci;