外键没有默认值
[英]Foreign key doesn't have a default value
问题描述
this is my User.java 
这是我的User.java
@Entity
@Table(name = "user")
public class User implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID")
private int id;
@Column(name = "FIRST_NAME")
private String firstName;
@Column(name = "LAST_NAME")
private String lastName;
@Column(name = "EMAIL")
private String email;
@OneToMany(cascade={CascadeType.ALL})
@JoinColumn(name="USER_ID")
private Collection<Address> addresses;
}
and this is my Address.java 这是我的Address.java
@Entity
@Table(name = "address")
public class Address implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID")
private int id;
@Column(name = "TOWN")
private String town;
@Column(name = "DISTRICT")
private String district;
@Column(name = "COUNTRY")
private String country;
@ManyToOne
@JoinColumn(name = "USER_ID", insertable=false, updatable=false, nullable=false)
private User user;
}
but while I'm trying to persist the object I'm getting this exception 但是当我试图持久化对象时，却遇到了这个异常
javax.servlet.ServletException: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not insert: [com.kpowd.model.Address]
javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
root cause
javax.faces.el.EvaluationException: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not insert: [com.kpowd.model.Address]
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:101)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:798)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1331)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:181)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:645)
root cause
javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not insert: [com.kpowd.model.Address]
org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1387)
org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1315)
org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1321)
org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:843)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
com.sun.proxy.$Proxy19.persist(Unknown Source)
com.kpowd.dao.basedao.GenericDaoImpl.create(GenericDaoImpl.java:47)
com.kpowd.service.impl.UserServiceImpl.registerUser(UserServiceImpl.java:34)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
com.sun.proxy.$Proxy20.registerUser(Unknown Source)
com.kpowd.controller.UserRegistrationBean.register(UserRegistrationBean.java:80)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.apache.el.parser.AstValue.invoke(AstValue.java:278)
org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:101)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:798)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1331)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:181)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:645)
root cause
org.hibernate.exception.GenericJDBCException: could not insert: [com.kpowd.model.Address]
org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:140)
org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:128)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64)
org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2345)
org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2852)
org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273)
org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320)
org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203)
org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129)
org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:69)
org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:179)
org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135)
org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:799)
org.hibernate.impl.SessionImpl.persist(SessionImpl.java:791)
org.hibernate.engine.EJB3CascadingAction$1.cascade(EJB3CascadingAction.java:48)
org.hibernate.engine.Cascade.cascadeToOne(Cascade.java:392)
org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:335)
org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204)
org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:425)
org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:362)
org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:338)
org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204)
org.hibernate.engine.Cascade.cascade(Cascade.java:161)
org.hibernate.event.def.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:475)
org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:353)
org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203)
org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129)
org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:69)
org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:179)
org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135)
org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:61)
org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:808)
org.hibernate.impl.SessionImpl.persist(SessionImpl.java:782)
org.hibernate.impl.SessionImpl.persist(SessionImpl.java:786)
org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:837)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
com.sun.proxy.$Proxy19.persist(Unknown Source)
com.kpowd.dao.basedao.GenericDaoImpl.create(GenericDaoImpl.java:47)
com.kpowd.service.impl.UserServiceImpl.registerUser(UserServiceImpl.java:34)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
com.sun.proxy.$Proxy20.registerUser(Unknown Source)
com.kpowd.controller.UserRegistrationBean.register(UserRegistrationBean.java:80)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.apache.el.parser.AstValue.invoke(AstValue.java:278)
org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:101)
javax.faces.component.UICommand.broadcast(UICommand.java:315)
javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:798)
javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1331)
com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:181)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:645)
root cause
java.sql.SQLException: Field 'USER_ID' doesn't have a default value
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1055)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3558)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3490)
com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2109)
com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2648)
com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2077)
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2362)
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2280)
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2265)
org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94)
org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57)
org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2345)
org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2852)
org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273)
org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320)
org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203)
org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129)
org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:69)
org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:179)
org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135)
org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:799)
org.hibernate.impl.SessionImpl.persist(SessionImpl.java:791)
org.hibernate.engine.EJB3CascadingAction$1.cascade(EJB3CascadingAction.java:48)
org.hibernate.engine.Cascade.cascadeToOne(Cascade.java:392)
org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:335)
org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204)
org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:425)
org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:362)
org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:338)
org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204)
org.hibernate.engine.Cascade.cascade(Cascade.java:161)
org.hibernate.event.def.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:475)
org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:353)
org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203)
org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129)
org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:69)
org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:179)
org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135)
org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:61)
org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:808)
org.hibernate.impl.SessionImpl.persist(SessionImpl.java:782)
org.hibernate.impl.SessionImpl.persist(SessionImpl.java:786)
org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:837)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:601)
org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
com.sun.proxy.$Proxy19.persist(Unknown Source)
com.kpowd.dao.basedao.GenericDaoImpl.create(GenericDaoImpl.java:47)
com.kpowd.service.impl.UserServiceImpl.registerUser(UserServiceImpl.java:34)
Error wont come if i remove the "NOTNULL" Constraint from the FORIGN_KEY "USER_ID" but i need to make it as a NOTNULL Column how should i want to do that. 如果我从FORIGN_KEY“ USER_ID”中删除了“ NOTNULL”约束，那么错误就不会出现，但是我需要将其作为NOTNULL列，我该怎么做。 please help me?? 请帮我？？
this is my register methode 这是我的注册方法
public String register() {
// Output some info
Address a = new Address();
a.setCountry("country1");
a.setDistrict("district1");
a.setTown("town");
Address b = new Address();
b.setCountry("country2");
b.setDistrict("district2");
b.setTown("town2");
List<Address> adrlist=new ArrayList<Address>();
adrlist.add(a);
adrlist.add(b);
User user = new User();
user.setFirstName("firstname");
user.setLastName("lastname");
user.setEmail("email");
user.setAddresses(adrlist);
// Call the business object to register the user
userService.registerUser(user);
// Set the message here
FacesMessage msg = new FacesMessage(FacesMessage.SEVERITY_INFO, "Registration success", "success");
FacesContext.getCurrentInstance().addMessage(null, msg);
System.out.println("befor redirect");
return "index?faces-redirect=true";
}
and this is my SQL Script 这是我的SQL脚本
CREATE DATABASE IF NOT EXISTS `myshop`;
USE `myshop`;
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`FIRST_NAME` varchar(45) DEFAULT NULL,
`LAST_NAME` varchar(45) DEFAULT NULL,
`EMAIL` varchar(45) DEFAULT NULL,
PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=46 DEFAULT CHARSET=utf8;
DROP TABLE IF EXISTS `address`;
CREATE TABLE `address` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`TOWN` varchar(45) DEFAULT NULL,
`DISTRICT` varchar(45) DEFAULT NULL,
`COUNTRY` varchar(45) DEFAULT NULL,
`USER_ID` int(11) NOT NULL,
PRIMARY KEY (`ID`),
KEY `FK_USER_idx` (`USER_ID`),
CONSTRAINT `FK_USER` FOREIGN KEY (`USER_ID`) REFERENCES `user` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8;
3 个解决方案
解决方案1
1 2014-06-18 05:41:28
To me, it looks like you have specified your relationship wrong. 对我来说，您似乎指定了错误的关系。 Have a look my Q&A here . 在这里查看我的问答。 You specifically want to be looking at the uni-directional 1 to many example. 您特别希望查看单向1对多示例。 With your current configuration I think Hibernate is trying to create 2 uni-directional 1 to many relationships and that is causing issues. 使用您当前的配置，我认为Hibernate尝试创建2个单向1到许多关系，这正在引起问题。
Specifying insertable = false, updateable = false, nullable = false on your @JoinColumn annotation won't be doing anything. 在@JoinColumn批注中指定insertable = false, updateable = false, nullable = false @JoinColumn insertable = false, updateable = false, nullable = false不会做任何事情。 Those modifiers only do something if you are using Hibernate to create your database schema based on your annotations. 仅当您使用Hibernate基于注释创建数据库模式时，这些修饰符才会起作用。 Since you already have a schema, it doesn't do anything. 由于您已经有一个架构，因此它不会执行任何操作。
It would be helpful for debugging purposes if you could post your registerUser method. 如果可以发布registerUser方法，则对调试很有帮助。
public class Address implements Serializable {
....
@ManyToOne
@JoinColumn(name = "USER_ID")
private User user;
}
public class User implements Serializable{
....
@OneToMany(mappedBy = "user", cascade = CascadeType.ALL)
private Collection<Address> addresses;
}
解决方案2
1 2014-06-18 05:53:37
As the exception you are getting is java.sql.SQLException: Field 'USER_ID' doesn't have a default value You can set a default value for your column in Hibernate using annotation like @JoinColumn(name = "USER_ID", insertable=false, updatable=false, nullable=false), columnDefinition = “int default 100" 作为异常，您将得到java.sql.SQLException: Field 'USER_ID' doesn't have a default value您可以使用@JoinColumn(name = "USER_ID", insertable=false, updatable=false, nullable=false), columnDefinition = “int default 100"注解@JoinColumn(name = "USER_ID", insertable=false, updatable=false, nullable=false), columnDefinition = “int default 100"注解为Hibernate中的列设置默认值。 @JoinColumn(name = "USER_ID", insertable=false, updatable=false, nullable=false), columnDefinition = “int default 100"
You can give any value in spite of 100 what you want to be your default value. 尽管可以将默认值设为100，但您仍可以给出任何值。
Second thing, may be you would like to add somewhere referencedColumnName = "SOME_COLUMN" when you are making foreign keys. 第二件事，可能是您在制作外键时希望在某处添加referencedColumnName = "SOME_COLUMN" 。
Hope it helps. 希望能帮助到你。
Edit: 编辑：
Please let me explain a bit, the referencedColumnName can be used to specify another column as the default id column of the other table. 请让我解释一下，referencedColumnName可用于将另一列指定为另一张表的默认ID列。
Table1
id int identity
tableb_key varchar
Table2
id int identity
key varchar unique
// in class for Table1
@Joincolumn(column="tableb_key", referencedColumnName="key")
解决方案3
-1 2017-02-28 12:28:09
When doing OneToMany and ManyToOne, you have to do add Parent object in you Chilid object as well Child in Parent Ojbect I mean you need to do a.setUser(user); 当进行OneToMany和ManyToOne时，您必须在Chilid对象中添加Parent对象以及在Parent Ojbect中添加Child对象，这意味着您需要执行a.setUser（user）;。 b.setUser(user); b.setUser（用户）;
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