Question

我想将MySQL JSON列映射到JPA。我做了一些研究，然后使用

@Type( type = "json" )
@Column( columnDefinition = "json" )

但这会引发异常

Exception in thread "main" org.hibernate.boot.registry.classloading.spi.ClassLoadingException: Unable to load class [json]
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:348)
    at org.hibernate.boot.internal.ClassLoaderAccessImpl.classForName(ClassLoaderAccessImpl.java:62)
    at org.hibernate.cfg.annotations.SimpleValueBinder.fillSimpleValue(SimpleValueBinder.java:538)
    at org.hibernate.cfg.SetSimpleValueTypeSecondPass.doSecondPass(SetSimpleValueTypeSecondPass.java:25)
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1621)
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1579)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:278)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:858)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:885)
    at org.hibernate.jpa.HibernatePersistenceProvider.createEntityManagerFactory(HibernatePersistenceProvider.java:58)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:55)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:39)
    at com.savemonk.ce.utility.hibernateAndJPA.JPAUtility.getEntityManagerFactory(JPAUtility.java:12)
    at com.savemonk.ce.v2.pricegraph.manager.AddNewPriceTrackRecord.addNewPriceTrackRecordTest(AddNewPriceTrackRecord.java:29)
    at com.savemonk.ce.v2.pricegraph.manager.AddNewPriceTrackRecord.main(AddNewPriceTrackRecord.java:23)
Caused by: java.lang.ClassNotFoundException: Could not load requested class : json
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl$AggregatedClassLoader.findClass(ClassLoaderServiceImpl.java:336)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.classForName(ClassLoaderServiceImpl.java:345)
    ... 14 more

我知道@Type是休眠的org.hibernate.annotations.Type 在JPA中映射列的正确方法是什么？

如果需要，我可以发布实体类。任何解释JPA + JSON-type-column的链接和资源都会有很大帮助。

Answer 1

在找到有关此问题的更多资源后，我碰到了vladmihalcea的这篇文章。

https://vladmihalcea.com/how-to-map-json-objects-using-generic-hibernate-types/

他的Hibernate类型库解决了JSON和JPA的各种问题。

Answer 2

除了依赖以外，您还需要添加

@TypeDef(name = "json", typeClass = JsonStringType.class)

到您的实体类声明之一

将MySQL JSON列映射到JPA会引发错误

2 个答案: