Hibernate 查询返回所需的结果，但有时相同数据上的列表为空

Question

对于我的 (Spring/Hibernate 4.3.11) 申请活动俱乐部组织由会员组织的室内和室外活动，我对我的 Activity 表进行了 Hibernate 查询，该表应该返回登录的活动member 是组织者或参与者之一。从概念上讲，它可以称为“我的活动”。

HQL 看起来像：

select a from Activity as a where (a.organizer = :member or :member in elements(a.participants)) order by a.dateFrom asc, a.timeFrom asc

启动应用程序后，查询返回预期结果。似乎生成了一堆单独的 SQL 查询（从 HQL 到 SQL 的转换对我来说仍然有些神秘！）

在应用程序中单击后，突然查询不再返回任何结果。未进行任何数据更改。

似乎是在单击触发以下代码的活动的编辑链接后出现问题：

public String getActivityForm(@ModelAttribute("loggedinMember") Member loggedinMember, @PathVariable("id") int id, ModelMap model) {
    Activity activity = service.findActivityById(id);
    if (! activity.getOrganizer().equals(loggedinMember)) {
        //throw exception, you can only edit an activity organized by you
        System.out.println("You are not the organizer of this activity!");
    }
    model.addAttribute("activity", activity);
    return "activityform";  
}

这里没有做任何奇怪的事情，所以我真的不知道什么会触发这个问题。

我查看了生成的 SQL，在没有返回结果的情况下，这要短得多。 SQL 块很长，但我将它们发布在下面。 显然，为每一行生成单独的 SQL 查询！ 我真的迷失了，这个问题在我使用更新版本的 Hibernate 后第一次出现。 那么有什么想法...？

SQL 生成所需结果：

Hibernate: 
    select
        activityca0_.id as id1_1_,
        activityca0_.description as descript2_1_ 
    from
        activitycategory activityca0_
Hibernate: 
    select
        activityre0_.id as id1_2_,
        activityre0_.description as descript2_2_ 
    from
        activityregion activityre0_
Hibernate: 
    select
        activity0_.id as id1_0_,
        activity0_.category_id as categor10_0_,
        activity0_.date_from as date_fro2_0_,
        activity0_.date_to as date_to3_0_,
        activity0_.description as descript4_0_,
        activity0_.meetingpoint as meetingp5_0_,
        activity0_.organizer_id as organiz11_0_,
        activity0_.price as price6_0_,
        activity0_.region_id as region_12_0_,
        activity0_.time_from as time_fro7_0_,
        activity0_.time_to as time_to8_0_,
        activity0_.title as title9_0_ 
    from
        activity activity0_ 
    where
        activity0_.organizer_id=? 
        or ? in (
            select
                participan1_.member_id 
            from
                member_activity_subscription participan1_ 
            where
                activity0_.id=participan1_.activity_id
        ) 
    order by
        activity0_.date_from asc,
        activity0_.time_from asc
Hibernate: 
    select
        activityca0_.id as id1_1_0_,
        activityca0_.description as descript2_1_0_ 
    from
        activitycategory activityca0_ 
    where
        activityca0_.id=?
Hibernate: 
    select
        member0_.id as id1_3_0_,
        member0_.active as active2_3_0_,
        member0_.birthdate as birthdat3_3_0_,
        member0_.city as city4_3_0_,
        member0_.email as email5_3_0_,
        member0_.firstname as firstnam6_3_0_,
        member0_.interests as interest7_3_0_,
        member0_.lastname as lastname8_3_0_,
        member0_.lastname_prefix as lastname9_3_0_,
        member0_.loginname as loginna10_3_0_,
        member0_.mobilephone as mobilep11_3_0_,
        member0_.password as passwor12_3_0_,
        member0_.summary as summary13_3_0_ 
    from
        member member0_ 
    where
        member0_.id=?
Hibernate: 
    select
        activityre0_.id as id1_2_0_,
        activityre0_.description as descript2_2_0_ 
    from
        activityregion activityre0_ 
    where
        activityre0_.id=?
Hibernate: 
    select
        activityca0_.id as id1_1_0_,
        activityca0_.description as descript2_1_0_ 
    from
        activitycategory activityca0_ 
    where
        activityca0_.id=?
Hibernate: 
    select
        member0_.id as id1_3_0_,
        member0_.active as active2_3_0_,
        member0_.birthdate as birthdat3_3_0_,
        member0_.city as city4_3_0_,
        member0_.email as email5_3_0_,
        member0_.firstname as firstnam6_3_0_,
        member0_.interests as interest7_3_0_,
        member0_.lastname as lastname8_3_0_,
        member0_.lastname_prefix as lastname9_3_0_,
        member0_.loginname as loginna10_3_0_,
        member0_.mobilephone as mobilep11_3_0_,
        member0_.password as passwor12_3_0_,
        member0_.summary as summary13_3_0_ 
    from
        member member0_ 
    where
        member0_.id=?
Hibernate: 
    select
        activityre0_.id as id1_2_0_,
        activityre0_.description as descript2_2_0_ 
    from
        activityregion activityre0_ 
    where
        activityre0_.id=?
Hibernate: 
    select
        activityca0_.id as id1_1_0_,
        activityca0_.description as descript2_1_0_ 
    from
        activitycategory activityca0_ 
    where
        activityca0_.id=?
Hibernate: 
    select
        member0_.id as id1_3_0_,
        member0_.active as active2_3_0_,
        member0_.birthdate as birthdat3_3_0_,
        member0_.city as city4_3_0_,
        member0_.email as email5_3_0_,
        member0_.firstname as firstnam6_3_0_,
        member0_.interests as interest7_3_0_,
        member0_.lastname as lastname8_3_0_,
        member0_.lastname_prefix as lastname9_3_0_,
        member0_.loginname as loginna10_3_0_,
        member0_.mobilephone as mobilep11_3_0_,
        member0_.password as passwor12_3_0_,
        member0_.summary as summary13_3_0_ 
    from
        member member0_ 
    where
        member0_.id=?
Hibernate: 
    select
        activityca0_.id as id1_1_0_,
        activityca0_.description as descript2_1_0_ 
    from
        activitycategory activityca0_ 
    where
        activityca0_.id=?
Hibernate: 
    select
        activityre0_.id as id1_2_0_,
        activityre0_.description as descript2_2_0_ 
    from
        activityregion activityre0_ 
    where
        activityre0_.id=?
Hibernate: 
    select
        activityca0_.id as id1_1_0_,
        activityca0_.description as descript2_1_0_ 
    from
        activitycategory activityca0_ 
    where
        activityca0_.id=?
Hibernate: 
    select
        participan0_.activity_id as activity1_0_0_,
        participan0_.member_id as member_i2_4_0_,
        member1_.id as id1_3_1_,
        member1_.active as active2_3_1_,
        member1_.birthdate as birthdat3_3_1_,
        member1_.city as city4_3_1_,
        member1_.email as email5_3_1_,
        member1_.firstname as firstnam6_3_1_,
        member1_.interests as interest7_3_1_,
        member1_.lastname as lastname8_3_1_,
        member1_.lastname_prefix as lastname9_3_1_,
        member1_.loginname as loginna10_3_1_,
        member1_.mobilephone as mobilep11_3_1_,
        member1_.password as passwor12_3_1_,
        member1_.summary as summary13_3_1_ 
    from
        member_activity_subscription participan0_ 
    inner join
        member member1_ 
            on participan0_.member_id=member1_.id 
    where
        participan0_.activity_id=?
Hibernate: 
    select
        participan0_.activity_id as activity1_0_0_,
        participan0_.member_id as member_i2_4_0_,
        member1_.id as id1_3_1_,
        member1_.active as active2_3_1_,
        member1_.birthdate as birthdat3_3_1_,
        member1_.city as city4_3_1_,
        member1_.email as email5_3_1_,
        member1_.firstname as firstnam6_3_1_,
        member1_.interests as interest7_3_1_,
        member1_.lastname as lastname8_3_1_,
        member1_.lastname_prefix as lastname9_3_1_,
        member1_.loginname as loginna10_3_1_,
        member1_.mobilephone as mobilep11_3_1_,
        member1_.password as passwor12_3_1_,
        member1_.summary as summary13_3_1_ 
    from
        member_activity_subscription participan0_ 
    inner join
        member member1_ 
            on participan0_.member_id=member1_.id 
    where
        participan0_.activity_id=?
Hibernate: 
    select
        participan0_.activity_id as activity1_0_0_,
        participan0_.member_id as member_i2_4_0_,
        member1_.id as id1_3_1_,
        member1_.active as active2_3_1_,
        member1_.birthdate as birthdat3_3_1_,
        member1_.city as city4_3_1_,
        member1_.email as email5_3_1_,
        member1_.firstname as firstnam6_3_1_,
        member1_.interests as interest7_3_1_,
        member1_.lastname as lastname8_3_1_,
        member1_.lastname_prefix as lastname9_3_1_,
        member1_.loginname as loginna10_3_1_,
        member1_.mobilephone as mobilep11_3_1_,
        member1_.password as passwor12_3_1_,
        member1_.summary as summary13_3_1_ 
    from
        member_activity_subscription participan0_ 
    inner join
        member member1_ 
            on participan0_.member_id=member1_.id 
    where
        participan0_.activity_id=?
Hibernate: 
    select
        participan0_.activity_id as activity1_0_0_,
        participan0_.member_id as member_i2_4_0_,
        member1_.id as id1_3_1_,
        member1_.active as active2_3_1_,
        member1_.birthdate as birthdat3_3_1_,
        member1_.city as city4_3_1_,
        member1_.email as email5_3_1_,
        member1_.firstname as firstnam6_3_1_,
        member1_.interests as interest7_3_1_,
        member1_.lastname as lastname8_3_1_,
        member1_.lastname_prefix as lastname9_3_1_,
        member1_.loginname as loginna10_3_1_,
        member1_.mobilephone as mobilep11_3_1_,
        member1_.password as passwor12_3_1_,
        member1_.summary as summary13_3_1_ 
    from
        member_activity_subscription participan0_ 
    inner join
        member member1_ 
            on participan0_.member_id=member1_.id 
    where
        participan0_.activity_id=?
Hibernate: 
    select
        participan0_.activity_id as activity1_0_0_,
        participan0_.member_id as member_i2_4_0_,
        member1_.id as id1_3_1_,
        member1_.active as active2_3_1_,
        member1_.birthdate as birthdat3_3_1_,
        member1_.city as city4_3_1_,
        member1_.email as email5_3_1_,
        member1_.firstname as firstnam6_3_1_,
        member1_.interests as interest7_3_1_,
        member1_.lastname as lastname8_3_1_,
        member1_.lastname_prefix as lastname9_3_1_,
        member1_.loginname as loginna10_3_1_,
        member1_.mobilephone as mobilep11_3_1_,
        member1_.password as passwor12_3_1_,
        member1_.summary as summary13_3_1_ 
    from
        member_activity_subscription participan0_ 
    inner join
        member member1_ 
            on participan0_.member_id=member1_.id 
    where
        participan0_.activity_id=?
Hibernate: 
    select
        participan0_.activity_id as activity1_0_0_,
        participan0_.member_id as member_i2_4_0_,
        member1_.id as id1_3_1_,
        member1_.active as active2_3_1_,
        member1_.birthdate as birthdat3_3_1_,
        member1_.city as city4_3_1_,
        member1_.email as email5_3_1_,
        member1_.firstname as firstnam6_3_1_,
        member1_.interests as interest7_3_1_,
        member1_.lastname as lastname8_3_1_,
        member1_.lastname_prefix as lastname9_3_1_,
        member1_.loginname as loginna10_3_1_,
        member1_.mobilephone as mobilep11_3_1_,
        member1_.password as passwor12_3_1_,
        member1_.summary as summary13_3_1_ 
    from
        member_activity_subscription participan0_ 
    inner join
        member member1_ 
            on participan0_.member_id=member1_.id 
    where
        participan0_.activity_id=?
Aantal activiteiten: 6
Handling GET request, activities = [nl.drsklaus.activiteitensite.model.Activity@8070e879, nl.drsklaus.activiteitensite.model.Activity@ac6b814e, nl.drsklaus.activiteitensite.model.Activity@e5b2a54b, nl.drsklaus.activiteitensite.model.Activity@97726734, nl.drsklaus.activiteitensite.model.Activity@2d0defe, nl.drsklaus.activiteitensite.model.Activity@f2f57489]

SQL 生成空结果：

Hibernate: 
    select
        activityca0_.id as id1_1_,
        activityca0_.description as descript2_1_ 
    from
        activitycategory activityca0_
Hibernate: 
    select
        activityre0_.id as id1_2_,
        activityre0_.description as descript2_2_ 
    from
        activityregion activityre0_
Hibernate: 
    select
        activity0_.id as id1_0_,
        activity0_.category_id as categor10_0_,
        activity0_.date_from as date_fro2_0_,
        activity0_.date_to as date_to3_0_,
        activity0_.description as descript4_0_,
        activity0_.meetingpoint as meetingp5_0_,
        activity0_.organizer_id as organiz11_0_,
        activity0_.price as price6_0_,
        activity0_.region_id as region_12_0_,
        activity0_.time_from as time_fro7_0_,
        activity0_.time_to as time_to8_0_,
        activity0_.title as title9_0_ 
    from
        activity activity0_ 
    where
        activity0_.organizer_id=? 
        or ? in (
            select
                participan1_.member_id 
            from
                member_activity_subscription participan1_ 
            where
                activity0_.id=participan1_.activity_id
        ) 
    order by
        activity0_.date_from asc,
        activity0_.time_from asc
Aantal activiteiten: 0
Handling GET request, activities = []

议程（我的活动）页面的代码如下所示：

@RequestMapping(value = "/subscribed", method = RequestMethod.GET)
public String home(@ModelAttribute("loggedinMember") Member member, ModelMap model) {

List<Activity> activities = service.findAllActivitiesForMember(member, true);
System.out.println("Aantal activiteiten: " + activities.size());

System.out.println("Handling GET request, activities = " + activities);     
model.addAttribute("activitiessubscribed", activities);
return "myactivities";
}

service 方法被委托给 dao 方法，如下所示：

@Override
public List<Activity> findAllActivitiesForMember(Member member, boolean upcoming) {

String hql = "select a from Activity as a where (a.organizer = :member or :member in elements(a.participants))";

if (upcoming) {
    hql += " order by a.dateFrom asc, a.timeFrom asc";
} else {
    hql += " order by a.dateTo desc, a.timeTo desc";
}

System.out.println("HQL: " + hql);
Query query = this.getSession().createQuery(hql);

query.setEntity("member", member);
return query.list();
}

使用以下网址：

第一次访问我的活动议程（正常结果： http://localhost:8080/ActiviteitenSite/activities/subscribed

选择特定活动： http://localhost:8080/ActiviteitenSite/activities/3

返回（仍然是正常结果）： http://localhost:8080/ActiviteitenSite/activities/subscribed

编辑活动（屏幕显示活动详细信息，不提交）： http://localhost:8080/ActiviteitenSite/activities/3/edit

再次访问我的议程（结果现在为空）： http://localhost:8080/ActiviteitenSite/activities/subscribed

Answer 1

我发现了 Member 对象（在登录期间保存在会话中）被破坏的位置： 在调用getActivityForm handler方法的时候，loggedinMember对象的id值（最初是1000）变成了@PathVariable id参数，也就是activity的id。 这确实不应该发生，但在这种方法中确实发生了。从那时起，成员对象包含错误的 id 属性值，并且查询不再起作用。这种情况如何发生以及为什么发生仍然是个谜。

public String getActivityForm(@ModelAttribute("loggedinMember") Member loggedinMember, @PathVariable("id") int id, ModelMap model) {
Activity activity = service.findActivityById(id);
if (! activity.getOrganizer().equals(loggedinMember)) {
    //throw exception, you can only edit an activity organized by you
    System.out.println("You are not the organizer of this activity!");
}
model.addAttribute("activity", activity);
return "activityform";  
}

编辑： 问题确实是 @PathVariable("id) 值与 @ModelAttribute("loggedinMember") 对象的 id 属性匹配，最后一个被修改。根据 SpringMVC 文档，这是预期的行为，但恕我直言，这是不需要的并且非常不合逻辑，我认为这是一个严重而讨厌的 Spring MVC 错误。

通过将“id”模型属性重命名为“activityId”来解决此问题，这样就不会再发生这种不需要的和意外的匹配。

@RequestMapping(value = "/{activityId}/edit", method = RequestMethod.GET)
public String getActivityForm(@ModelAttribute("loggedinMember") Member loggedinMember, @PathVariable("activityId") int activityId, ModelMap model) {
Activity activity = service.findActivityById(activityId);
if (! activity.getOrganizer().equals(loggedinMember)) {
        //throw exception, you can only edit an activity organized by you
System.out.println("Je bent niet de organisator van deze activiteit!");
}
model.addAttribute("activity", activity);
   return "activityform";   
}