无法确定类型：java.util.Set，在表中

Posted 2023-04-12

【中文标题】无法确定类型：java.util.Set，在表中

【英文标题】：Could not determine type for: java.util.Set, at table

【发布时间】：2017-11-11 09:47:32

【问题描述】：

我创建了两个具有多对多关系的类，如下所示：

@Entity
@Table(name = FoodEntity.TABLE_NAME)
public class FoodEntity extends BaseEntity<Long> 

public static final String TABLE_NAME = "T_FOOD";

@ManyToMany
@JoinTable(
    name = "T_FOOD_FOODCATEGORY",
    joinColumns =        @JoinColumn(name = "FOOD_ID") , 
    inverseJoinColumns =     @JoinColumn(name = "FOOD_CATEGORY_ID") )
private Set<FoodCategoryEntity> categories;

public Set<FoodCategoryEntity> getCategories() 
return categories;


public void setCategories(Set<FoodCategoryEntity> categories) 
this.categories = categories;


@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "FOOD_ID", nullable = false)
@Override
public Long getId() 
return id;


@Override
public void setId(Long id) 
this.id = id;

和：

@Entity
@Table(name = FoodCategoryEntity.TABLE_NAME)
public class FoodCategoryEntity extends BaseEntity<Long> 

public static final String TABLE_NAME = "T_FOOD_CATEGORY";

@ManyToMany(mappedBy = "categories")
private Set<FoodEntity> foods;

public Set<FoodEntity> getFoods() 
return foods;


public void setFoods(Set<FoodEntity> foods) 
this.foods = foods;


@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "FOOD_CATEGORY_ID", nullable = false)
@Override
public Long getId() 
return id;


@Override
public void setId(Long id) 
this.id = id;

但是当我用 junit、spring 和 hibernate 测试这种关系时，我得到以下异常：

Caused by: org.hibernate.MappingException: Could not determine type for: java.util.Set, at table: T_FOOD, for columns: [org.hibernate.mapping.Column(categories)]
at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:455)
at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:422)
at org.hibernate.mapping.Property.isValid(Property.java:226)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:597)
at org.hibernate.mapping.RootClass.validate(RootClass.java:265)
at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:329)
at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:451)
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:889)
... 46 more

我检查了注解包引用和所有 ID 列名，但它们都是正确的。 要点：我也使用HSQLDB数据库，它的存储位置是一个文件。

【问题讨论】：

org.hibernate.MappingException: Could not determine type for: java.util.List, at table: College, for columns: [org.hibernate.mapping.Column(students)]的可能重复

【参考方案1】：

我发现了我的问题。 persistence.xml 中的映射类不正确。

【参考方案2】：

您的注释推断属性访问类型映射，因为@Id 放置在 getter 上

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "FOOD_ID", nullable = false)
@Override
public Long getId() 
    return id;

但是集合注释放在字段级别

@ManyToMany
@JoinTable(
    name = "T_FOOD_FOODCATEGORY",
    joinColumns =        @JoinColumn(name = "FOOD_ID") , 
    inverseJoinColumns =     @JoinColumn(name = "FOOD_CATEGORY_ID") )
private Set<FoodCategoryEntity> categories;

虽然（未）在 getter 上指定有效配置

public Set<FoodCategoryEntity> getCategories() 
    return categories;

您不应混合使用两种类型的配置。

【讨论】：

当我将类别字段上的注释位置更改为方法时，我得到以下异常：原因：org.hibernate.AnnotationException：使用 OneToMany 或 ManyToMany 以未映射的类为目标：ir.msr.projects.crawler。 food.entity.FoodEntity.categories[ir.msr.projects.crawler.food.entity.FoodCategoryEntity]

第二个不扫描。测试配置问题？