[英]detached entity when using ManyToMany in jpa 2.1
我正在創建一個應用程序,我在Recipe
和Ingredients
之間有一個ManyToMany關系,但是當我嘗試使用JPA 2.1在RecipeIngredient
插入新行時,我得到了:
引起:javax.persistence.PersistenceException:org.hibernate.PersistentObjectException:傳遞給persist的分離實體。
這是我的實體:`
@Entity
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
@CrossCheck
public class Ingredient implements ValidEntity {
static final String PREFIX = "com.architech.sales.ingredient.entity.";
public static final String FIND_ALL = PREFIX + "FIND_ALL";
public static final String FIND_BY_ID = PREFIX + "FIND_BY_ID";
@Id
@GeneratedValue
private long id;
@NotNull
private String label;
private String description;
// added just to reply to @Maciej-Kowalski
@OneToMany(targetEntity = RecetteIngredient.class, mappedBy = "ingredient")
private List<RecetteIngredient> recetteIngredients;
@Version
private long version;
// Getter / Setter
}
@Entity
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
@CrossCheck
public class Recette implements ValidEntity{
static final String PREFIX = "sales.recette.entity.Recette.";
public static final String FIND_ALL = PREFIX + "FIND_ALL";
public static final String FIND_BY_ID = PREFIX + "FIND_BY_ID";
@Id
@GeneratedValue
private long id;
@Size(min = 1, max = 256)
private String label;
private String description;
@OneToMany(targetEntity = RecetteIngredient.class, mappedBy = "recette")
private List<RecetteIngredient> recetteIngredients;
@Version
private long version;
// Getter/Setter
}
`
`
@Entity
@IdClass(RecetteIngredientPK.class)
public class RecetteIngredient implements Serializable{
@Id
private long id;
private double qte;
@Id
@ManyToOne(targetEntity = Ingredient.class)
private Ingredient ingredient;
@Id
@ManyToOne(targetEntity = Recette.class)
private Recette recette;
// Getter/Setter
}
`
和我的持久單位
<?xml version="1.0" encoding="UTF-8"?> <persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"> <persistence-unit name="prod" transaction-type="JTA"> <properties> <property name="javax.persistence.schema-generation.database.action" value="drop-and-create"/> <!--<property name="hibernate.enable_lazy_load_no_trans" value="true" />--> </properties> </persistence-unit> </persistence>
這是堆棧跟蹤:
`
Caused by: javax.persistence.PersistenceException: org.hibernate.PersistentObjectException: detached entity passed to persist: com.architech.sales.ingredient.entity.Ingredient
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1608)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.merge(AbstractEntityManagerImpl.java:1171)
at org.jboss.as.jpa.container.AbstractEntityManager.merge(AbstractEntityManager.java:565)
at com.architech.sales.recette_ingredient.boundary.RecetteIngredientManager.save(RecetteIngredientManager.java:47)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
`
這就是我試圖持久化RecetteIngredient的方法:
`
@Stateless
@Interceptors(BoundaryLogger.class)
public class RecetteIngredientManager {
@PersistenceContext
EntityManager em;
public RecetteIngredient findById(long id) {
return this.em.find(RecetteIngredient.class, id);
}
public void delete(long id) {
try {
RecetteIngredient reference = this.em.getReference(RecetteIngredient.class, id);
this.em.remove(reference);
} catch (EntityNotFoundException e) {
//we want to remove it...
}
}
public RecetteIngredient save(RecetteIngredient recetteIngredient) {
return this.em.merge(recetteIngredient);
}
}
`
在鏈接類中,在@ManyToOne
映射上添加merge cascade選項:
@Entity
@IdClass(RecetteIngredientPK.class)
public class RecetteIngredient implements Serializable{
@Id
private long id;
private double qte;
@Id
@ManyToOne(targetEntity = Ingredient.class, cascade = CascadeType.MERGE)
private Ingredient ingredient;
@Id
@ManyToOne(targetEntity = Recette.class, cascade = CascadeType.MERGE)
private Recette recette;
這將建議PersistenceContext同時合並Ingredient和Recette實體,如果它們恰好在當時被分離。
如果您不允許更改注釋,則必須在持久化鏈接表之前手動保留/合並Ingredient和Recette實體:
public RecetteIngredient save(RecetteIngredient recette) {
this.em.merge(recette.getIngredient());
this.em.merge(recette.getRecette());
return this.em.merge(recette);
}
當然這是一種解決方法,第一種方法肯定更優雅,更可取。
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