无法使用 Spring Boot 运行此 JPA 代码

【问题标题】：Unable to Run this JPA Code using Spring Boot无法使用 Spring Boot 运行此 JPA 代码
【发布时间】：2018-11-30 03:18:28
【问题描述】：

我创建了具有一对一共享主键关系的简单 JPA Spring 应用程序，该项目具有以下结构

project structure 代码在哪里

Book.java

 package com.example.demo.model;
    import javax.persistence.*;
    import java.io.Serializable;

    @Entity
    public class Book implements Serializable {
        @Id
        @GeneratedValue
        private Long id;
        private String bookName;

        @OneToOne(mappedBy = "book")
        private BookDetail bookDetail;

        public Book() {
        }
        public Book(String bookName) {

            this.bookName=bookName;
        }

        public Book(String bookName,BookDetail bookDetail) {
            this.bookName=bookName;
            this.bookDetail=bookDetail;
            this.bookDetail.setBook(this);
        }

        public Long getId() {
            return id;
        }

        public void setId(Long id) {
            this.id = id;
        }

        public String getBookName() {
            return bookName;
        }

        public void setBookName(String bookName) {
            this.bookName = bookName;
        }


        public BookDetail getBookDetail() {
            return bookDetail;
        }

        public void setBookDetail(BookDetail bookDetail) {
            this.bookDetail = bookDetail;
        }

        @Override
        public String toString() {
            return "Book{" +
                    "id=" + id +
                    ", bookName='" + bookName + '\'' +
                    ", bookDetail=" + bookDetail +
                    '}';
        }
    }

BookDetail.java


 package com.example.demo.model;

    import javax.persistence.Entity;
    import javax.persistence.Id;
    import javax.persistence.JoinColumn;
    import javax.persistence.OneToOne;
    import java.io.Serializable;

    @Entity
    public class BookDetail implements Serializable {
        private int noOfPages;

        @Id
        @OneToOne
        @JoinColumn(name="id")
        private Book book;


        public BookDetail() {
        }
        public BookDetail(int noOfPages)
        {
            this.noOfPages=noOfPages;
        }

        public int getNoOfPages() {
            return noOfPages;
        }

        public void setNoOfPages(int noOfPages) {
            this.noOfPages = noOfPages;
        }


        public Book getBook() {
            return book;
        }

        public void setBook(Book book) {
            this.book = book;
        }

        @Override
        public String toString() {
            return "BookDetail{" +
                    "noOfPages=" + noOfPages +
                    ", book=" + book +
                    '}';
        }
    }

BookRepository.java


 package com.example.demo.repository;

    import org.springframework.data.jpa.repository.JpaRepository;
    import com.example.demo.model.Book;

    public interface BookRepository extends JpaRepository<Book,Long> {
    }

BookService.java

package com.example.demo.service;

import com.example.demo.model.BookDetail;
import com.example.demo.model.Book;
import com.example.demo.repository.BookRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;

@Service
public class BookService {
    @Autowired
    private BookRepository bookRepository;

    public BookService() {
    }

    public BookRepository getBookRepository() {
        return bookRepository;
    }

    public void setBookRepository(BookRepository bookRepository) {
        this.bookRepository = bookRepository;
    }


    @PostConstruct
    public void loadData()
    {
        Book book=new Book("Java",new BookDetail(134));
        bookRepository.save(book);

    }
}


and finally DemoApplication.java



 package com.example.demo;

    import com.example.demo.service.BookService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;

    @SpringBootApplication
    public class DemoApplication {
        @Autowired
        BookService bookService;

        public static void main(String[] args) {



            SpringApplication.run(DemoApplication.class, args);
        }
    }


When i run this , i am getting the following error

启动 ApplicationContext 时出错。要显示条件报告，请在启用“调试”的情况下重新运行您的应用程序。 2018-06-21 02:57:21.909 错误 14892 --- [restartedMain] os.s.boot.SpringApplication：应用程序运行失败

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demoApplication': Unsatisfied dependency expressed through field 'bookService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'bookService': Invocation of init method failed; nested exception is org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:587) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:373) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1350) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:580) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:760) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at com.example.demo.DemoApplication.main(DemoApplication.java:17) [classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_171]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_171]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_171]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_171]
    at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-2.0.3.RELEASE.jar:2.0.3.RELEASE]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'bookService': Invocation of init method failed; nested exception is org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:138) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:424) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1700) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:581) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:503) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:251) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1065) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:584) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    ... 24 common frames omitted
Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail
    at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:364) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:227) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:540) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:746) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:714) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:532) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:304) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135) ~[spring-data-jpa-2.0.8.RELEASE.jar:2.0.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.0.8.RELEASE.jar:2.0.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at com.sun.proxy.$Proxy87.save(Unknown Source) ~[na:na]
    at com.example.demo.service.BookService.loadData(BookService.java:32) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_171]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_171]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_171]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_171]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleElement.invoke(InitDestroyAnnotationBeanPostProcessor.java:365) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor$LifecycleMetadata.invokeInitMethods(InitDestroyAnnotationBeanPostProcessor.java:308) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.beans.factory.annotation.InitDestroyAnnotationBeanPostProcessor.postProcessBeforeInitialization(InitDestroyAnnotationBeanPostProcessor.java:135) ~[spring-beans-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    ... 36 common frames omitted
Caused by: java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:146) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:157) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.ExceptionConverterImpl.convert(ExceptionConverterImpl.java:164) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1443) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:494) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:3245) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2451) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:473) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:156) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:231) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:68) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:536) ~[spring-orm-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    ... 60 common frames omitted
Caused by: org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.example.demo.model.Book.bookDetail -> com.example.demo.model.BookDetail
    at org.hibernate.engine.spi.CascadingActions$8.noCascade(CascadingActions.java:380) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:142) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.event.internal.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:150) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:141) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:74) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:38) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.SessionImpl.doFlush(SessionImpl.java:1437) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    ... 69 common frames omitted



Kindly help me in eliminating the bug

【问题讨论】：

  • 完整代码可在以下链接中找到github.com/arulsuju/One2OneRelationship
  • org.hibernate.TransientPropertyValueException 这意味着您没有在 Book 实体之前保存 BookDetail 实体。

标签： spring-boot jpa


【解决方案1】：

@Arul Suju 这里 BookDetails 是你的父类。在 Book Class 中，您 ma​​ppedBy 与 book。在 BookDetails 中创建的 book 列。所以在保存 Book 之前strong> 你必须保存 BookDetails..

这里你必须检查我的代码

https://drive.google.com/open?id=1sq_z9ywzy0vduCGZoE9mIecB9ICtIEGw

【讨论】：

【解决方案2】：

您必须像下面这样手动设置 jpa 的 id，因为您没有为 JPA 中的 id 字段使用任何 @Generator 注释。 @Generator 注解自动为你生成 id。

private void loadData()
    {
        BookDetail bookDetail=new BookDetail();
        bookDetail.setId(20002);
        Book book=new Book();
        book.setId(10001);
        bookDetail.setBook(book);
        book.setBookDetail(bookDetail);
        book.setBookName("Java");
        bookDetail.setNoofPages(1234);
        bookDetailRepository.save(bookDetail);
        bookRepository.save(book);

    }

【讨论】：

  • 谢谢。但我想为 Book 和 Book Detail 分配公共 ID。它实际上是一个主键。我们如何编写代码
【解决方案3】：

我得到了解决方案，我修改了 Book Details 类，如下所示

package com.example.demo;

import javax.annotation.Generated;
import javax.persistence.*;
import java.io.Serializable;

@Entity
public class BookDetail implements Serializable {


    private int noofPages;

    @Id
    @OneToOne
    @JoinColumn(name="book_id")
    private Book book;

    public BookDetail() {
    }



    public int getNoofPages() {
        return noofPages;
    }

    public void setNoofPages(int noofPages) {
        this.noofPages = noofPages;
    }

    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

    @Override
    public String toString() {
        return "BookDetail{"
                +
                ", noofPages=" + noofPages +
                ", book=" + book +
                '}';
    }
}

完整的代码可在以下github链接中获得

https://github.com/arulsuju/1to1demo

【讨论】：

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