spring boot mapper層傳參數是用main的arg0(第一個參數),arg1(第二個參數)
大于三個參數,用map傳遞
public interface FrontMapper{
//==============
//spring boot mapper 傳參
@Select("select count(1) as num from users where username=#{arg0} and password=#{arg1}")
int isUserExist(String username,String password);