java创建触发器失败（Missing IN or OUT parameter at index:: 1 ）

create or replace trigger trigger_33zOtisNB5cZ_LMAhwtmDg
before insert or update of STUNAME
on T_STU for each row
begin
if inserting then
insert into table_33zOtisNB5cZ_LMAhwtmDg values ('insert',sysdate,:new.STUID);
elsif updating then
insert into table_33zOtisNB5cZ_LMAhwtmDg values ('update',sysdate,:new.STUID);
elsif deleting then
insert into table_33zOtisNB5cZ_LMAhwtmDg values ('delete',sysdate,:old.STUID);
end if;end;

PreparedStatement state = conn.prepareCall(sql);
state.execute();

Statement state = conn.createStatement();
state.execute(sql);