All geek questions in one place

How can I create a relationship between two classes in different data sources?

I am working on a web application that has 3 data sources: we can name them DS1 , DS2 and DS3 . Each of them is a physical database.

So, I added a configuration for each of these data sources, with a different entity manager, etc.

Inside DS1 , I have an entity E1 , and in the second data source, E2 . Now I need to create a relationship between these two objects.

So, I added something like:

public class E1 { ... @OneToOne private E2 e2; ... }

But I have the following error:

 org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManager' defined in class path resource [it/mux/config/datasource/DataSourceMuxConfig.class]: Invocation of init method failed; nested exception is org.hibernate.AnnotationException: @OneToOne or @ManyToOne on it.mux.domain.amministrazione.Bo.e2 references an unknown entity: it.mux.cliente.domain.E2 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1080) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:857) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.10.RELEASE.jar:1.5.10.RELEASE] at it.mux.MuxApplication.main(MuxApplication.java:21) [classes/:na] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_161] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_161] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_161] at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.5.10.RELEASE.jar:1.5.10.RELEASE] Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on it.mux.domain.amministrazione.E1.e2 references an unknown entity: it.mux.cliente.domain.E2 at org.hibernate.cfg.ToOneFkSecondPass.doSecondPass(ToOneFkSecondPass.java:97) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final] at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processEndOfQueue(InFlightMetadataCollectorImpl.java:1786) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final] at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processFkSecondPassesInOrder(InFlightMetadataCollectorImpl.java:1730) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final] at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1617) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final] at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:847) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final] at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:874) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final] at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:60) ~[spring-orm-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:360) ~[spring-orm-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:382) ~[spring-orm-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:371) ~[spring-orm-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:336) ~[spring-orm-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) ~[spring-beans-4.3.14.RELEASE.jar:4.3.14.RELEASE] ... 21 common frames omitted

First of all, is it possible to do this?

If so, how can I fix this?

+5
source share
1 answer

This would not be possible out of the box, as these objects are in separate save contexts.

Creating a custom composite persistence context and synchronizing it with Hibernate will take a lot of effort.

For a one-to-one (or any other) relationship, you can implement something like:

 List<E1> e1s = repositoryDS1.findAllE1(); List<E2> e2s = repositoryDS2.findAllE2(); List<E1E2Aggregate> = mapper.map(e1s, e2s);
0
source

Source: https://habr.com/ru/post/1276154/

More articles:


All Articles