org.hibernate.PersistentObjectException：传递给持久化的分离实体：多对一单向

Posted 2023-02-24

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【中文标题】org.hibernate.PersistentObjectException：传递给持久化的分离实体：多对一单向【英文标题】：org.hibernate.PersistentObjectException: detached entity passed to persist: Many to one unidirectional 【发布时间】：2021-02-23 09:53:27 【问题描述】：

我正在尝试在 Spring Boot 中使用休眠模式进行多对一单向映射。我有以下学生班-很多

package jpa.many.to.one.unidirectional.model;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
 
@Entity
@Table(name = "STUDENT")
public class Student 
 
    @Id
    @GeneratedValue
    @Column(name = "STUDENT_ID")
    private long id;
 
    @Column(name = "FIRST_NAME")
    private String firstName;
 
    @Column(name = "LAST_NAME")
    private String lastName;
 
    @Column(name = "SECTION")
    private String section;
 
    @ManyToOne(cascade = CascadeType.ALL)
    @JoinColumn(name="UNIVERSITY_ID")
    private University university;
 
 
    public Student() 
    
 
    public Student(String firstName, String lastName, String section, University university) 
        this.firstName = firstName;
        this.lastName = lastName;
        this.section = section;
        this.university = university;
    
 
    public long getId() 
        return id;
    
 
    public void setId(long id) 
        this.id = id;
    
 
    public String getFirstName() 
        return firstName;
    
 
    public void setFirstName(String firstName) 
        this.firstName = firstName;
    
 
    public String getLastName() 
        return lastName;
    
 
    public void setLastName(String lastName) 
        this.lastName = lastName;
    
 
    public String getSection() 
        return section;
    
 
    public void setSection(String section) 
        this.section = section;
    
 
    public University getUniversity() 
        return university;
    
 
    public void setUniversity(University university) 
        this.university = university;
    
 
    @Override
    public String toString() 
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName="
                + lastName + ", section=" + section + "]";

大学 - 一节课

package jpa.many.to.one.unidirectional.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
 
@Entity
@Table(name = "UNIVERSITY")
public class University 
 
    @Id
    @GeneratedValue
    @Column(name = "UNIVERSITY_ID")
    private long id;
 
    @Column(name = "NAME")
    private String name;
 
    @Column(name = "COUNTRY")
    private String country;
 
    public University() 
 
    
 
    public University(String name, String country) 
        this.name = name;
        this.country = country;
    
 
    public long getId() 
        return id;
    
 
    public void setId(long id) 
        this.id = id;
    
 
    public String getName() 
        return name;
    
 
    public void setName(String name) 
        this.name = name;
    
 
    public String getCountry() 
        return country;
    
 
    public void setCountry(String country) 
        this.country = country;
    
 
    @Override
    public String toString() 
        return "University [id=" + id + ", name=" + name + ", country=" + country + "]";

应用程序保存并运行为

package jpa.many.to.one.unidirectional;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;

import jpa.many.to.one.unidirectional.model.Student;
import jpa.many.to.one.unidirectional.model.University;
import jpa.many.to.one.unidirectional.repo.StudentRepo;
import jpa.many.to.one.unidirectional.repo.UniversityRepo;

@SpringBootApplication
public class Application 

    public static void main(String[] args) 
//      SpringApplication.run(Application.class, args);

        ConfigurableApplicationContext configurableApplicationContext = SpringApplication.run(Application.class, args);
        UniversityRepo universityRepo = configurableApplicationContext.getBean(UniversityRepo.class);
        StudentRepo studentRepo = configurableApplicationContext.getBean(StudentRepo.class);

        University university = new University("MG", "India");
        
        Student fstudent = new Student("Deeksha", "Sivakumar", "A", university);
        fstudent.setUniversity(university);
        studentRepo.save(fstudent);
        
        
        Student fstudent1 = new Student("Sivakumar", "Nair", "A", university);
        fstudent1.setUniversity(university);
        studentRepo.save(fstudent1);

但我明白了引起：org.hibernate.PersistentObjectException：分离的实体传递给坚持：jpa.many.to.one.unidirectional.model.University 在 org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:120) 在 org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:113) 在 org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:744) 在 org.hibernate.internal.SessionImpl.persist(SessionImpl.java:712) 在 org.hibernate.engine.spi.CascadingActions$7.cascade(CascadingActions.java:298) 在 org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:492) 在 org.hibernate.engine.internal.Cascade.cascadeAssociation（Cascade.java:416）在 org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:218) 在 org.hibernate.engine.internal.Cascade.cascade(Cascade.java:151) 在 org.hibernate.event.internal.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:427) 在 org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:264) 在 org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:193) 在 org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:135) 在 org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient（DefaultPersistEventListener.java:185）在 org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:128) 在 org.hibernate.event.internal.DefaultPersistEventListener.onPersist（DefaultPersistEventListener.java:55）在 org.hibernate.event.service.internal.EventListenerGroupImpl.fireEventOnEachListener(EventListenerGroupImpl.java:102) 在 org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:720) 在 org.hibernate.internal.SessionImpl.persist(SessionImpl.java:706) 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 在 java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 在 java.base/java.lang.reflect.Method.invoke(Method.java:567) 在 org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:314) 在 com.sun.proxy.$Proxy55.persist（未知来源）在 org.springframework.data.jpa.repository.support.SimpleJpaRepository.save（SimpleJpaRepository.java:554）在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 在 java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 在 java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 在 java.base/java.lang.reflect.Method.invoke(Method.java:567) 在 org.springframework.data.repository.core.support.ImplementationInvocationMetadata.invoke（ImplementationInvocationMetadata.java:72）在 org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:382) 在 org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:205) 在 org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:550) 在 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) 在 org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:155) 在 org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:130) 在 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) 在 org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:80) 在 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) 在 org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:367) 在 org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118) 在 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) 在 org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ... 13 更多

我在多对一注释中尝试了 cascade.merge 和 optional-=false。但我收到上述错误请帮忙

【问题讨论】：

【参考方案1】：

@ManyToOne(cascade = CascadeType.ALL) 在您的情况下，这似乎是一个坏主意，因为删除学生会导致删除相关的大学。由于大学可以有多个学生，其他学生将成为孤儿

我认为你应该在 University Entity 中使用这种关系，而不是 Student Entity

@OneToMany(cascade = CascadeType.ALL)
@JoinColumn(name="STUDENT_ID")
private List<Student> students;

如果您想使用您的模型，请在将其设置为学生之前尝试保存大学（因为在您的代码中，您尝试保存相同的大学两次，第一次使用 fstudent，第二次使用 fstudent1），在这种情况下我建议你不要使用级联：

  University university = universityRepo.save(new University("MG", "India"));
    
    Student fstudent = new Student("Deeksha", "Sivakumar", "A", university);
    fstudent.setUniversity(university);
    studentRepo.save(fstudent);
    
    
    Student fstudent1 = new Student("Sivakumar", "Nair", "A", university);
    fstudent1.setUniversity(university);
    studentRepo.save(fstudent1);

【讨论】：

早安阿扎比！！！感谢您的回复。在设置学生价值观和大学价值观之前，我为大学明确保存。还删除了所有级联，并在学生班的大学参考中给出了@ManyToOne(optional = false) ...我的要求是学生实体应该为每个学生提供大学参考现在我得到了预期的结果我还有一个问题...保持相同的关系..如何插入具有相同大学 ID 的新孩子我也没有找到接受的选项...请告诉我在哪里可以做到这一点对于你的问题，需要设置save返回的大学，或者通过id搜索并设置在Student中

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