Hibernate uniqueResult为空，但不应该为空
Hibernate uniqueResult为空，但不应该为空
提问于 2015-12-15 09:32:38
早上好,
我想做以下几件事：
在更新对象之前，我希望从最后一个记录中检索一个字段，以便将其添加到新行中。所以这就是我所做的
int idLuce = Integer.parseInt(msg);
Illuminazione illuminazione = new Illuminazione();
session.beginTransaction();
selectQuery = "SELECT dateTime from Illuminazione i where i.idLuce = :idLuce ORDER BY i.dateTime ASC";
theQuery = session.createQuery(selectQuery).setProperties(illuminazione).setFirstResult(0)
.setMaxResults(1);
lastDate = (Date) theQuery.uniqueResult();
logger.debug("last date time is: "+lastDate);
illuminazione.setLastDateTime(lastDate);
illuminazione.setIdLuce(idLuce);
illuminazione.setIsLit(true);
Date date = new Date();
illuminazione.setDateTime(new Timestamp(date.getTime()));
session.save(illuminazione);
session.getTransaction().commit();一切如我所料，但lastDate是空的.我没有错误或异常，这是操作的日志。
2015-12-15 10:30:01.157 DEBUG [Thread-2]: HQL: SELECT dateTime from it.besmart.models.Illuminazione i where i.idLuce = :idLuce ORDER BY i.dateTime ASC
2015-12-15 10:30:01.159 DEBUG [Thread-2]: SQL: select illuminazi0_.date_time as col_0_0_ from SMARTPARK.illuminazione illuminazi0_ where illuminazi0_.id_luce=? order by illuminazi0_.date_time ASC
2015-12-15 10:30:01.161 DEBUG [Thread-2]: throwQueryException() : no errors
Hibernate:
select
illuminazi0_.date_time as col_0_0_
from
SMARTPARK.illuminazione illuminazi0_
where
illuminazi0_.id_luce=?
order by
illuminazi0_.date_time ASC limit ?
2015-12-15 10:30:01.187 DEBUG [Thread-2]: last date time is: null
2015-12-15 10:30:01.285 DEBUG [Thread-2]: Executing identity-insert immediately
2015-12-15 10:30:01.314 DEBUG [Thread-2]:
insert
into
SMARTPARK.illuminazione
(date_time, id_luce, isLit, last_date_time)
values
(?, ?, ?, ?)
Hibernate:
insert
into
SMARTPARK.illuminazione
(date_time, id_luce, isLit, last_date_time)
values
(?, ?, ?, ?)显然，如果我在SQL中运行相同的查询，它会工作.
我做错什么了？谢谢
回答 1
Stack Overflow用户
回答已采纳
发布于 2015-12-15 10:14:57
您似乎没有将idLuce传递到查询中。尝尝这个
int idLuce = Integer.parseInt(msg);
session.beginTransaction();
selectQuery = "SELECT dateTime from Illuminazione i where i.idLuce = :idLuce ORDER BY i.dateTime ASC";
theQuery = session.createQuery(selectQuery).setParameter("idLuce", idLuce).setMaxResults(1);
lastDate = (Date) theQuery.uniqueResult();或者，在执行查询之前移动illuminazione.setIdLuce(idLuce);行。
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原文链接：
https://stackoverflow.com/questions/34285516
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