Spring Data jpa（hibernate）nullpointer添加实体列表时的异常

问题描述

限时删除！！

首先是我的代码。

专业化

  @Entity 
公共类专业化{
 
 @Id 
私人字符串名称; 
 
 @OneToMany（cascade = CascadeType.ALL）
 @JoinColumn（name =att_id，referencedColumnName =ID）
 private List< Attribute>属性; 
 
 // Getters and Setters 
} 
  

属性

  @Entity 
公共类属性{
 
 @Id 
 @GeneratedValue（strategy = GenerationType.AUTO）
私人长ID; 
 
私人字符串名称; 
私人双倍缩放; 
 
 // Getters and Setters 
} 
  

我的问题是我得到以下异常：

 由org.hibernate.cfg引发java.lang.NullPointerException 
。 annotations.CollectionBinder.bindCollectionSecondPass（CollectionBinder.java:1460）
处org.hibernate.cfg.annotations.CollectionBinder org.hibernate.cfg.annotations.CollectionBinder.bindOneToManySecondPass（CollectionBinder.java:864）
。 bindStarToManySecondPass（CollectionBinder.java:779）
在org.hibernate.cfg.annotations.CollectionBinder $ 1.secondPass（CollectionBinder.java:728）
在org.hibernate.cfg.CollectionSecondPass.doSecondPass（CollectionSecondPass.java ：在org.hibernate.cfg.Configuration.originalSecondPassCompile（Configuration.java:1697 70）
）
在org.hibernate.cfg.Configuration.secondPassCompile（Configuration.java:1426）
。在org.hibernate.cfg.Configuration.buildSessionFactory（Configuration.java:1846）
在org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl $ 4.perform（EntityManagerFactoryBuilderImpl.java:852）$ B $在org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl $ 4.perform（EntityManagerFactoryBuilderImpl.java:845）$ B B $ b。在org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl（ClassLoaderServiceImpl.java:398）
在org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build（EntityManagerFactoryBuilderImpl.java:844） 
 at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory（SpringHibernateJpaPersistenceProvider.java:60）
 at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory（LocalContainerEntityManagerFactoryBean.java:343）
 at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet（AbstractEntityManagerFactoryBean.java:318）
 at org.springframework.beans .factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods（AbstractAutowireCapableBeanFactory.java:1625）
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean（AbstractAutowireCapableBeanFactory.java:1562）
 ... 98 more 
  

仅在添加属性属性后发生此异常。到类专业化。所以没有这个属性一切正常，但如果我添加此属性，异常出现。我不明白我做错了什么。
也许有人可以找到我的错误？

其他信息：

Hibernate核心版本：4.3.7。最后。

还有另一个实体 GameClass ，与Specialization = OneToMany的关系每个 GameClass 有多个 Specialization s，每一个 Specialization 都有多个属性 s。

不知道这是否重要，但这是一个Spring-Boot应用程序

解决方案

我弄错了。睡觉有点帮助。
如果一个 Specialization 有许多属性 s，注释应该如下所示：

  @OneToMany（cascade = CascadeType.ALL ）
 @JoinColumn（name =specc_id，referencedColumnName =name）
 private List< Attribute>属性; 
  

和不是像这样：

  @OneToMany（cascade = CascadeType.ALL）
 @JoinColumn（name =att_id，referencedColumnName =ID）
 private List<属性>属性; 
  

first my Code.

Specialization

@Entity
public class Specialization {

    @Id
    private String name;

    @OneToMany(cascade = CascadeType.ALL)
    @JoinColumn(name="att_id", referencedColumnName="ID")
    private List<Attribute> attributes;

    //Getters and Setters
}

Attribute

@Entity
public class Attribute {

    @Id
    @GeneratedValue(strategy= GenerationType.AUTO)
    private Long id;

    private String name;
    private double scaling;

    //Getters and Setters
}

My Problem is that i get a following Exception:

Caused by: java.lang.NullPointerException
    at org.hibernate.cfg.annotations.CollectionBinder.bindCollectionSecondPass(CollectionBinder.java:1460)
    at org.hibernate.cfg.annotations.CollectionBinder.bindOneToManySecondPass(CollectionBinder.java:864)
    at org.hibernate.cfg.annotations.CollectionBinder.bindStarToManySecondPass(CollectionBinder.java:779)
    at org.hibernate.cfg.annotations.CollectionBinder$1.secondPass(CollectionBinder.java:728)
    at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:70)
    at org.hibernate.cfg.Configuration.originalSecondPassCompile(Configuration.java:1697)
    at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1426)
    at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1846)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:852)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:845)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:398)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:844)
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60)
    at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:343)
    at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1625)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1562)
    ... 98 more

This Exception only Occurs after adding the attribute attributes to the Class Specialization. So without this attribute everything works fine, but if I add this attribute, the exception comes up. I don't get what I'm doing wrong.Maybe somebody could find my mistake?

Additional information:

Hibernate Core Version: 4.3.7. Final.

There is another Entity GameClass with a oneToMany relationship to Specialization => Every GameClass has multiple Specializations and every Specialization has multiple Attributes.

Don't know if this matters but this is a Spring-Boot application

解决方案

I've got my mistake. Sleeping a bit helped.I've mixed up the relations.

If one Specialization has many Attributes, the annotations should look like this:

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name="specc_id", referencedColumnName = "name")
private List<Attribute> attributes;

and NOT like this:

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name="att_id", referencedColumnName="ID")
private List<Attribute> attributes;

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