在调用save（）之前，必须手动分配这个类的ID，

本文介绍了在调用save（）之前，必须手动分配这个类的ID，的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述 我遇到了hibernate @OneToMany 映射的问题。它就像这里

  @Entity 
 @Table（name =albums）
 @SequenceGenerator（ NAME = aLBUMS_SEQ，sequenceName = albums_seq，allocationSize = 1）
公共类AlbumDs {
 
 @Id @GeneratedValue（策略= GenerationType.SEQUENCE，发电机= aLBUMS_SEQ）
私人整数ID; 
 private Integer ownerId; 
私人字符串名称; 
私有字符串描述; 
私人创建日期; 
 @OneToMany（cascade = CascadeType.ALL）
 @JoinColumn（name =albumId，insertable = true，updatable = true）
 private Set< UserAlbumDs> users = new HashSet< UserAlbumDs>（）; 
 
 public Integer getId（）{
 return id; 
} 
 public void setId（Integer id）{
 this.id = id; 
} 
 public Integer getOwnerId（）{
 return ownerId; 
} 
 public void setOwnerId（Integer ownerId）{
 this.ownerId = ownerId; 
} 
 public String getName（）{
 return name; 
} 
 public void setName（String name）{
 this.name = name; 
} 
 public String getDescription（）{
 return description; 
} 
 public void setDescription（String description）{
 this.description = description; 
} 
 public Date getCreated（）{
 return created; 
} 
 public void setCreated（创建日期）{
 this.created = created; 
} 
 public void setUsers（Set< UserAlbumDs> users）{
 this.users = users; 
} 
 public Set< UserAlbumDs> getUsers（）{
返回用户; 
 
 
  

UseraAlbumDs
$ p $ @Entity
@Table（name =users_albums）
public class UserAlbumDs {

@Id
private Integer userId;
@Id
私人整数albumId;

public Integer getUserId（）{
return userId;
}
public void setUserId（Integer userId）{
this.userId = userId;
}
public Integer getAlbumId（）{
return albumId;
}
public void setAlbumId（Integer albumId）{
this.albumId = albumId;




当我调用 save（我得到了异常：

  SEVERE：Servlet.service（）for servlet [main] in上下文与路径[/ Kronika]抛出异常[请求处理失败;嵌套异常是org.hibernate.id.IdentifierGenerationException：必须在调用save（）之前手动分配此类的ids（eu.patrykdobrowolski.model.hibernate.UserAlbumDs），其根源为
 org.hibernate.id.IdentifierGenerationException：在调用save（）之前，必须手动分配此类的id：eu.patrykdobrowolski.model.hibernate.UserAlbumDs $ b $ org.hibernate.id.Assigned.generate（Assigned.java:33）$ b $ org .hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId（AbstractSaveEventListener.java:99）
 at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId（DefaultSaveOrUpdateEventListener.java:187）
 at org.hibernate.event .def.DefaultSaveOrUpdateEventListener.entityIsTransient（DefaultSaveOrUpdateEventListener.java:172）
 at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate（DefaultSaveOrUpdateEventListener.java:94）
 at org.hibernate.event.def.Deful tSaveOrUpdateEventListener.onSaveOrUpdate（DefaultSaveOrUpdateEventListener.java:70）
 at org.hibernate.impl.SessionImpl.fireSaveOrUpdate（SessionImpl.java:507）
 at org.hibernate.impl.SessionImpl.saveOrUpdate（SessionImpl.java： 499）
 at org.hibernate.engine.CascadingAction $ 5.cascade（CascadingAction.java:218）
 at org.hibernate.engine.Cascade.cascadeToOne（Cascade.java:268）
 at org.hibernate.engine.Cascade.cascadeAssociation（Cascade.java:216）
位于org.hibernate.engine.Cascade.cascadeProperty（Cascade.java:169）
位于org.hibernate.engine.Cascade。 cascadeCollectionElements（Cascade.java:296）
在org.hibernate.engine.Cascade.cascadeCollection（Cascade.java:242）
在org.hibernate.engine.Cascade.cascadeAssociation（Cascade.java:219） 
在org.hibernate.engine.Cascade.cascadeProperty（Cascade.java:169）
在org.hibernate.engine.Cascade.cascade（Cascade.java:130）
在org.hibernate .event.def.AbstractSaveEventListener.ca （org.hibernate.event.def.AbstractSaveEventListener.performSave（AbstractSaveEventListener）中的
。 Java的：181），美元，org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId（AbstractSaveEventListener.java:121 b $ b）
在org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId（DefaultSaveOrUpdateEventListener.java:187） 
 at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId（DefaultSaveEventListener.java:33）
 at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient（DefaultSaveOrUpdateEventListener.java:172）
 at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate（DefaultSaveEventListener.java:27）
 at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate（De faultSaveOrUpdateEventListener.java:70）
在org.hibernate.impl.SessionImpl.fireSave（SessionImpl.java:535）
在org.hibernate.impl.SessionImpl.save（SessionImpl.java:523）
 at org.hibernate.impl.SessionImpl.save（SessionImpl.java:519）
 at eu.patrykdobrowolski.dao.hibernate.HibernateAlbumDao.create（HibernateAlbumDao.java:26）
 at eu.patrykdobrowolski .service.impl.AlbumServiceImpl.createAlbum（AlbumServiceImpl.java:28）
 at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method）
 at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:39） 
 at sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:25）
 at java.lang.reflect.Method.invoke（Method.java:597）
 at org.springframework.aop .support.AopUtils.invokeJoinpointUsingReflection（AopUtils.java:309）
在org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint（ReflectiveMethodInvocation.java:1 
在org.springframework.transaction.interceptor.TransactionInterceptor.invoke（TransactionInterceptor.java:110）$ b在org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:150）
 $ b at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed（ReflectiveMethodInvocation.java:172）
 at org.springframework.aop.framework.JdkDynamicAopProxy.invoke（JdkDynamicAopProxy.java:202）
  

为什么hibernate无法自行分配这些ID？这里有什么不对？

首先 - 它不能生成它们，因为你没有告诉它如何去做。使用 @GeneratedValue 并选择你想要的策略。

然后 - 你不能有两个 @Id 字段。如果您想要一个复合标识符，请使用 @EmbeddedId 或 @IdClass

I've got some problem with hibernate @OneToMany mapping. It goes like here

@Entity
@Table(name = "albums")
@SequenceGenerator(name = "ALBUMS_SEQ", sequenceName = "albums_seq", allocationSize = 1)
public class AlbumDs {

    @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "ALBUMS_SEQ")
    private Integer id;
    private Integer ownerId;
    private String name;
    private String description;
    private Date created;
    @OneToMany(cascade = CascadeType.ALL) 
    @JoinColumn(name = "albumId", insertable = true, updatable = true)
    private Set<UserAlbumDs> users = new HashSet<UserAlbumDs>();

    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public Integer getOwnerId() {
        return ownerId;
    }
    public void setOwnerId(Integer ownerId) {
        this.ownerId = ownerId;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    public Date getCreated() {
        return created;
    }
    public void setCreated(Date created) {
        this.created = created;
    }
    public void setUsers(Set<UserAlbumDs> users) {
        this.users = users;
    }
    public Set<UserAlbumDs> getUsers() {
        return users;
    }
}

UseraAlbumDs:

@Entity
@Table(name = "users_albums")
public class UserAlbumDs {

    @Id
    private Integer userId;
    @Id
    private Integer albumId;

    public Integer getUserId() {
        return userId;
    }
    public void setUserId(Integer userId) {
        this.userId = userId;
    }
    public Integer getAlbumId() {
        return albumId;
    }
    public void setAlbumId(Integer albumId) {
        this.albumId = albumId;
    }
}

When I call save(albumDs) I get exception:

SEVERE: Servlet.service() for servlet [main] in context with path [/Kronika] threw exception [Request processing failed; nested exception is org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save(): eu.patrykdobrowolski.model.hibernate.UserAlbumDs] with root cause
org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save(): eu.patrykdobrowolski.model.hibernate.UserAlbumDs
    at org.hibernate.id.Assigned.generate(Assigned.java:33)
    at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:99)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:187)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:172)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:94)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
    at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:507)
    at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:499)
    at org.hibernate.engine.CascadingAction$5.cascade(CascadingAction.java:218)
    at org.hibernate.engine.Cascade.cascadeToOne(Cascade.java:268)
    at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:216)
    at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:169)
    at org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:296)
    at org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:242)
    at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:219)
    at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:169)
    at org.hibernate.engine.Cascade.cascade(Cascade.java:130)
    at org.hibernate.event.def.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:456)
    at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:334)
    at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:181)
    at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:121)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:187)
    at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:172)
    at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
    at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
    at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:535)
    at org.hibernate.impl.SessionImpl.save(SessionImpl.java:523)
    at org.hibernate.impl.SessionImpl.save(SessionImpl.java:519)
    at eu.patrykdobrowolski.dao.hibernate.HibernateAlbumDao.create(HibernateAlbumDao.java:26)
    at eu.patrykdobrowolski.service.impl.AlbumServiceImpl.createAlbum(AlbumServiceImpl.java:28)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)

Why hibernate can't assing those ids on its own? What's wrong here?

解决方案

First - it can't generate them because you didn't tell it how to do it. Use @GeneratedValue and choose the strategy you want.

Then - you can't have two @Id fields. If you want a composite id use @EmbeddedId or @IdClass

这篇关于在调用save（）之前，必须手动分配这个类的ID，的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！