Hibernate未能懒惰地初始化一个集合。

问题描述 投票：0回答：1

我在Spring Boot中设置了两个数据源。在一个控制器中，我想在这两个数据源上持久化一对父子实体。它们几乎是相同的双向关系，但第一个工作，而第二个发出提交消息，但实际上并没有持久化子实体。

@Entity
public class Brand {

private Integer id;

private Set<Line> lines = new HashSet<Line>(); 

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
@JsonIgnore
public Integer getId() {
    return id;
}

@JsonIgnore
@OneToMany(mappedBy = "brand", cascade = CascadeType.ALL, orphanRemoval = true)
public Set<Line> getLines() {
    return lines;
}

@Entity
public class Line {

private Integer id;

private Brand brand;

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public Integer getId() {
    return id;
}

@ManyToOne
@JoinColumn(name = "brand")
public Brand getBrand() {
    return brand;
}

而这些来自第二个数据源，它坚持父数据源，但不坚持子数据源。

@Entity
public class User {

private String id;

private List<UserCommit> userCommitList = new ArrayList<UserCommit>();

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public Integer getId() {
    return id;
}
}

@OneToMany(mappedBy = "user", cascade = CascadeType.ALL, orphanRemoval = true)
public List<UserCommit> getUserCommitList() {
    return userCommitList;
}

@Entity
public class UserCommit {

private Integer id;

private User user;

@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public Integer getId() {
    return id;
}

@ManyToOne
@JoinColumn(name = "user")
public User getUser() {
    return user;
}

这是控制器中最有趣的部分

    Brand brand = brandService.createFrom(fsDto.getBrand());
    Line line = lineService.createFrom(fsDto.getLine(), brand);
    AccessToken accToken = token.getAccount().getKeycloakSecurityContext().getToken();

    try {

        prodService.updateFrom(id, line, fsDto);

        User user = userService.createFrom(accToken);
        ucService.createFrom(user, id, "EDIT", "FIRST");

而这些都是服务方式

public Brand createFrom(String name) {

    Brand foundBrand = findByName(name);
    Brand brand = new Brand();
    if (foundBrand == null) {
        brand = brandRepo.save(brand);
        brand.setName(name);
    } else
        brand = foundBrand;

    return brand;

public Line createFrom(String name, Brand brand) {

    Line foundLine = findByNameAndBrand(name, brand);
    Line line = new Line();
    if (foundLine == null) {
        line.setName(name);
        line.setBrand(brand);
        line.getBrand().addLine(line);

    } else
        line = foundLine;

    return line;
}

public User createFrom(AccessToken accToken) {

    User user = findByKcId(accToken.getSubject());

    if(user == null) {
        user = new User();
        user.setKcId(accToken.getSubject());
        user.setName(accToken.getPreferredUsername());
        userRepo.save(user);
    }

    return user;

}

public UserCommit createFrom(User user, Integer prodId, String ucType, String stage) {

    UserCommit uc = new UserCommit();
    uc.setUser(user);
    uc.getUser().addUserCommit(uc);
    uc.setProdId(prodId);
    uc.setUCType(UserCommit.UCType.valueOf(ucType));
    uc.setStage(UserCommit.Stage.valueOf(stage));
    uc.setTime(LocalDateTime.now());

    return uc;
}
  • 品牌得到坚持。
  • 线路被持久化。
  • 用户被持久化。
  • UserCommit没有被持久化。
  • 如果我显式调用UserCommitService.save()，一切都能正常工作，但我想应该不需要。

编辑我更新了我的代码，使这两对事务更加相似，现在对于第二个事务，我得到了这个典型的懒惰初始化的错误。

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: petmenu.entities.users.User.userCommitList, could not initialize proxy - no Session

真正让我抓狂的是，Brand→Line能用，而User→UserCommit却不能用。即使追踪JPA，我也无法理解为什么UserCommit提交时User实体不包含在会话中。

2020-05-26 16:51:54.258 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Found thread-bound EntityManager [SessionImpl(1767213597<open>)] for JPA transaction
2020-05-26 16:51:54.258 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Creating new transaction with name [petmenu.services.users.UserService.createFrom]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
2020-05-26 16:51:54.259 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Exposing JPA transaction as JDBC [org.springframework.orm.jpa.vendor.HibernateJpaDialect$HibernateConnectionHandle@41ca5759]
2020-05-26 16:52:01.687 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.EntityManagerFactoryUtils    : Opening JPA EntityManager
2020-05-26 16:52:01.708 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] org.hibernate.SQL                        : select user0_.id as id1_0_, user0_.kc_id as kc_id2_0_, user0_.name as name3_0_ from user user0_ where user0_.kc_id=?
2020-05-26 16:52:01.708 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.h.type.descriptor.sql.BasicBinder      : binding parameter [1] as [VARCHAR] - [80a3b4b1-00d1-4062-a7e5-1927b938c203]
2020-05-26 16:52:01.709 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.h.type.descriptor.sql.BasicExtractor   : extracted value ([id1_0_] : [INTEGER]) - [2005]
2020-05-26 16:52:01.709 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.h.type.descriptor.sql.BasicExtractor   : extracted value ([kc_id2_0_] : [VARCHAR]) - [80a3b4b1-00d1-4062-a7e5-1927b938c203]
2020-05-26 16:52:01.709 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.h.type.descriptor.sql.BasicExtractor   : extracted value ([name3_0_] : [VARCHAR]) - [user1]
2020-05-26 16:52:01.709 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Triggering beforeCommit synchronization
2020-05-26 16:52:01.709 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Triggering beforeCompletion synchronization
2020-05-26 16:52:01.709 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Initiating transaction commit
2020-05-26 16:52:01.709 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Committing JPA transaction on EntityManager [SessionImpl(1767213597<open>)]
2020-05-26 16:53:06.630 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Triggering afterCommit synchronization
2020-05-26 16:53:06.671 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Triggering afterCompletion synchronization
2020-05-26 16:53:06.671 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Not closing pre-bound JPA EntityManager after transaction
2020-05-26 16:53:06.671 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Found thread-bound EntityManager [SessionImpl(1767213597<open>)] for JPA transaction
2020-05-26 16:53:06.671 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Creating new transaction with name [petmenu.services.users.UserCommitService.createFrom]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
2020-05-26 16:53:06.671 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Exposing JPA transaction as JDBC [org.springframework.orm.jpa.vendor.HibernateJpaDialect$HibernateConnectionHandle@323b85aa]
2020-05-26 16:53:17.438 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Triggering beforeCompletion synchronization
2020-05-26 16:53:17.472 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Initiating transaction rollback
2020-05-26 16:53:17.472 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Rolling back JPA transaction on EntityManager [SessionImpl(1767213597<open>)]
2020-05-26 16:53:17.472 TRACE 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Triggering afterCompletion synchronization
2020-05-26 16:53:17.472 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.s.orm.jpa.JpaTransactionManager        : Not closing pre-bound JPA EntityManager after transaction
2020-05-26 16:53:17.473 DEBUG 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.j.s.OpenEntityManagerInViewInterceptor : Closing JPA EntityManager in OpenEntityManagerInViewInterceptor
2020-05-26 16:53:17.496 ERROR 78269 --- [http-nio-192.168.1.10-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: petmenu.entities.users.User.userCommitList, could not initialize proxy - no Session] with root cause
hibernate spring-boot jpa persistence mariadb-10.3
1个回答
0
投票

我研究了很多关于事务管理的东西等等，我（希望）找到了罪魁祸首。但每一个纠正都会被感激地接受.

LSS

似乎Spring Boot注册了 OpenEntityManagerInViewInterceptor 只是为了主要的数据源（我在网上找到了一些关于这个的信息，但在官方文档上没有找到）。

TL:DR

将一个会话绑定到整个视图，并加载急于管理的实体集合，当执行 LineService.createFrom Brand的集合已经被持久化了，那么新添加的Line就会在交易结束时被刷新，而在没有view-session的对立面，我在里面没有管理集合。UserCommitService.createFrom 事务，那么在没有明确调用 UserCommitRepo.save UserCommit将保持瞬态，并将在事务提交时默默地从刷新中丢弃。

我不知道我的理解是否正确，如果是这样的话，我希望有人能解释一下在 CascadeType.PERSIST (包括在 CascadeType.ALL)上 @OneToMany 双向关系的一方。

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