Java JPA/Hibernate:@ManyToOne和@OneToOne关系标记为FetchType.LAZY和optional=false未在em.find（）上延迟加载？

我有以下实体（仅显示相关映射）：

请注意上面的注释：与其他实体之间有三种

@XToOne

关系：

用户（一个简单ID为PK的SecurityIdentity子类，由代表所有者的PQ引用）：

投标：

@Entity
@Table(name = "Tenderings")
public class Tendering implements Serializable
{
    @Id
    @Column(name = "pq_id", insertable = false, updatable = false)
    private Integer pqId;

    @Column(name = "external_code")
    private String externalCode;

    @OneToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "pq_id", referencedColumnName = "id")
    private PQ pq;

    ...
}

不要对共享ID的组和用户感到困惑，只需将它们视为简单的ID即可。投标只是一个单独的文件对象（一对一）

如您所见，PQ实体上有三个

@XToOne

关系，如果未设置获取类型，则会立即加载（JPA默认）。为了防止这种情况，我将所有

@XToOne

关系标记为

FetchType.LAZY

现在使用

em.find（PQ.class，someExistingId）

我得到Hibernate输出：

23:53:55,815 INFO  [stdout] Hibernate: select pq0_.id as id291_0_, pq0_.description as descript2_291_0_, pq0_.name as name291_0_, pq0_.submission_date as submission4_291_0_, pq0_.user_id as user5_291_0_ from PQs pq0_ where pq0_.id=?
23:53:55,818 INFO  [stdout] Hibernate: select user0_.id as id280_0_, user0_1_.identity_type_id as identity2_280_0_, user0_.is_enabled as is1_297_0_, user0_.name as name297_0_, user0_.password as password297_0_, user0_.person_id as person5_297_0_ from Users user0_ inner join SecurityIdentities user0_1_ on user0_.id=user0_1_.id where user0_.person_id=?
23:53:55,821 INFO  [stdout] Hibernate: select group0_.id as id280_0_, group0_1_.identity_type_id as identity2_280_0_, group0_.pq_id as pq2_281_0_ from Groups group0_ inner join SecurityIdentities group0_1_ on group0_.id=group0_1_.id where group0_.pq_id=?
23:53:55,823 INFO  [stdout] Hibernate: select tendering0_.pq_id as pq1_296_0_, tendering0_.binary_file as binary2_296_0_, tendering0_.customer_id as customer6_296_0_, tendering0_.description as descript3_296_0_, tendering0_.external_code as external4_296_0_, tendering0_.title as title296_0_ from Tenderings tendering0_ where tendering0_.pq_id=?

00:47:34,397 INFO  [stdout] Hibernate: select pq0_.id as id361_0_, pq0_.description as descript2_361_0_, pq0_.name as name361_0_, pq0_.submission_date as submission4_361_0_, pq0_.user_id as user5_361_0_ from PQs pq0_ where pq0_.id=?
00:47:34,410 INFO  [stdout] Hibernate: select user0_.id as id350_0_, user0_1_.identity_type_id as identity2_350_0_, user0_.is_enabled as is1_367_0_, user0_.name as name367_0_, user0_.password as password367_0_, user0_.person_id as person5_367_0_ from Users user0_ inner join SecurityIdentities user0_1_ on user0_.id=user0_1_.id where user0_.person_id=?
00:47:34,413 INFO  [stdout] Hibernate: select group0_.id as id350_0_, group0_1_.identity_type_id as identity2_350_0_, group0_.pq_id as pq2_351_0_ from Groups group0_ inner join SecurityIdentities group0_1_ on group0_.id=group0_1_.id where group0_.pq_id=?

这三个额外的选择源于@XToOne关系（如网上许多地方所述）。我主要关注的来源是：


如前所述，不应获取
@manytone
关系
用户
：

@ManyToOne（fetch=FetchType.LAZY）
应该可以正常工作

。。。这里是从PQ到User的关系，但是是从
select user0.id as id280\u 0\u>语句中可以看到的，
获取的

对于其他两个
组组
和
招标
，这两个
@OneToOne
反向映射，外键引用PQs表的PK（ID），从而在PQ实体中产生相同的映射

请注意，所有三种关系都不是可选的：PQ始终有所有者（用户），并且PQ始终由招标和集团实体引用。我只是还没有在上面的JPA中建模

因此，将
optional=false
添加到PQ实体的三个关系时：

@Entity
@Table(name = "PQs")
public class PQ implements Serializable
{
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column
    private Integer id;

    @Column
    private String name;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "user_id", referencedColumnName = "person_id")
    private User user;

    @OneToOne(mappedBy = "pq", fetch = FetchType.LAZY, optional = false)
    private Group group;

    @OneToOne(mappedBy = "pq", fetch = FetchType.LAZY, optional = false)
    private Tendering tendering;

    ...
}

。。。我得到以下Hibernate输出：

23:53:55,815 INFO  [stdout] Hibernate: select pq0_.id as id291_0_, pq0_.description as descript2_291_0_, pq0_.name as name291_0_, pq0_.submission_date as submission4_291_0_, pq0_.user_id as user5_291_0_ from PQs pq0_ where pq0_.id=?
23:53:55,818 INFO  [stdout] Hibernate: select user0_.id as id280_0_, user0_1_.identity_type_id as identity2_280_0_, user0_.is_enabled as is1_297_0_, user0_.name as name297_0_, user0_.password as password297_0_, user0_.person_id as person5_297_0_ from Users user0_ inner join SecurityIdentities user0_1_ on user0_.id=user0_1_.id where user0_.person_id=?
23:53:55,821 INFO  [stdout] Hibernate: select group0_.id as id280_0_, group0_1_.identity_type_id as identity2_280_0_, group0_.pq_id as pq2_281_0_ from Groups group0_ inner join SecurityIdentities group0_1_ on group0_.id=group0_1_.id where group0_.pq_id=?
23:53:55,823 INFO  [stdout] Hibernate: select tendering0_.pq_id as pq1_296_0_, tendering0_.binary_file as binary2_296_0_, tendering0_.customer_id as customer6_296_0_, tendering0_.description as descript3_296_0_, tendering0_.external_code as external4_296_0_, tendering0_.title as title296_0_ from Tenderings tendering0_ where tendering0_.pq_id=?

00:47:34,397 INFO  [stdout] Hibernate: select pq0_.id as id361_0_, pq0_.description as descript2_361_0_, pq0_.name as name361_0_, pq0_.submission_date as submission4_361_0_, pq0_.user_id as user5_361_0_ from PQs pq0_ where pq0_.id=?
00:47:34,410 INFO  [stdout] Hibernate: select user0_.id as id350_0_, user0_1_.identity_type_id as identity2_350_0_, user0_.is_enabled as is1_367_0_, user0_.name as name367_0_, user0_.password as password367_0_, user0_.person_id as person5_367_0_ from Users user0_ inner join SecurityIdentities user0_1_ on user0_.id=user0_1_.id where user0_.person_id=?
00:47:34,413 INFO  [stdout] Hibernate: select group0_.id as id350_0_, group0_1_.identity_type_id as identity2_350_0_, group0_.pq_id as pq2_351_0_ from Groups group0_ inner join SecurityIdentities group0_1_ on group0_.id=group0_1_.id where group0_.pq_id=?

请注意，我只在PQ实体上使用了
optional=false
，因为这是我在
em.find（…）
中使用的。（如果这还不够，请告诉我。）

我现在的问题有两个：

为什么对
用户
实体的
@ManyToOne
会被急切地获取（鉴于据说该实体工作很懒散，请参见）

为什么只有
OneToOne
与
招标
实体的关系没有被提取？是因为
招标
实体将PQ的PK列引用为PK本身（
招标
中的
@Id
），而
集团
实体没有引用PK（与PQ的PK有规则关系）
怎么了？如何使这些非可选关系变得懒惰？（没有代码插入或其他黑客，只有简单的注释…）

我知道LAZY只是一个提示，让JPA提供者做一些关于延迟加载的事情，或者不做，但是在这种情况下，似乎有其他事情是错误的（作为它工作的一部分）

PS：我使用的是Hibernate 4.0 BETA版，JBoss 7.0.0.Final附带的版本，只提供JPA注释（以上都是JPA 1.0兼容的）。
嗨，我不确定JPA，但是对于
多对一
和
一对一
映射，Hibernate支持的惰性值是
代理
，
无代理
和
false
默认为false。检查DTD的这一部分

lazy=“proxy |无代理| false”

你可以检查一下。我认为这在一定程度上回答了您的第一个问题。
*ToOne关系意味着在对象初始化之后必须有（代理）bean，一旦以任何方式访问它，它将触发select（您正在看到它），您确定您对可能强制加载的对象不做任何操作吗
 使用hibernate注释和jpa注释之间存在差异，据我所知，hibernate默认情况下是延迟加载的，但在某些情况下除外。下面是一个简短的讨论：

您好，您显示了额外的选择，因为它将对所有涉及的实体执行选择，请尝试使用FetchType.LAZY作为默认的一对多，在大多数情况下，使用FETCH JOIN来获得结果

我希望能帮助您或需要此信息的人
默认的
lazy=“proxy | no proxy | false”
是代理，正如您发布的链接（参见12）：“lazy（可选-默认为代理）：默认情况下，单点关联是代理的。lazy=“no proxy”“指定在首次访问实例变量时应延迟获取属性。这需要构建时字节码检测。lazy=“false”指定关联将始终被急切地获取。“可能这只是一个bug。请参阅，这是类似的。
00:47:34,397 INFO  [stdout] Hibernate: select pq0_.id as id361_0_, pq0_.description as descript2_361_0_, pq0_.name as name361_0_, pq0_.submission_date as submission4_361_0_, pq0_.user_id as user5_361_0_ from PQs pq0_ where pq0_.id=?
00:47:34,410 INFO  [stdout] Hibernate: select user0_.id as id350_0_, user0_1_.identity_type_id as identity2_350_0_, user0_.is_enabled as is1_367_0_, user0_.name as name367_0_, user0_.password as password367_0_, user0_.person_id as person5_367_0_ from Users user0_ inner join SecurityIdentities user0_1_ on user0_.id=user0_1_.id where user0_.person_id=?
00:47:34,413 INFO  [stdout] Hibernate: select group0_.id as id350_0_, group0_1_.identity_type_id as identity2_350_0_, group0_.pq_id as pq2_351_0_ from Groups group0_ inner join SecurityIdentities group0_1_ on group0_.id=group0_1_.id where group0_.pq_id=?