我的 spring 代码显示以下错误，这是由其中一个实体类引起的。 由于Spring/JPA没有提供有关错误来源的任何提示，因此我将不得不删除每个实体，直到找到罪魁祸首。 通常会给出线索，但这里的情况并非如此。
java.lang.IllegalStateException: Failed to load ApplicationContext
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:125) ~[spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108) ~[spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:118) ~[spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83) ~[spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener.prepareTestInstance(SpringBootDependencyInjectionTestExecutionListener.java:44) ~[spring-boot-test-autoconfigure-2.1.2.RELEASE.jar:2.1.2.RELEASE]
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246) ~[spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) [junit-4.12.jar:4.12]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) [junit-4.12.jar:4.12]
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) [junit-4.12.jar:4.12]
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.junit.runners.ParentRunner.run(ParentRunner.java:363) [junit-4.12.jar:4.12]
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190) [spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:365) [surefire-junit4-2.22.1.jar:2.22.1]
at org.apache.maven.surefire.junit4.JUnit4Provider.executeWithRerun(JUnit4Provider.java:273) [surefire-junit4-2.22.1.jar:2.22.1]
at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:238) [surefire-junit4-2.22.1.jar:2.22.1]
at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:159) [surefire-junit4-2.22.1.jar:2.22.1]
at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:384) [surefire-booter-2.22.1.jar:2.22.1]
at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:345) [surefire-booter-2.22.1.jar:2.22.1]
at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:126) [surefire-booter-2.22.1.jar:2.22.1]
at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:418) [surefire-booter-2.22.1.jar:2.22.1]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource [org/springframework/boot/autoconfigure/orm/jpa/HibernateJpaConfiguration.class]: Invocation of init method failed; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1745) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:576) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:498) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1083) ~[spring-context-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:853) ~[spring-context-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546) ~[spring-context-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) ~[spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) ~[spring-boot-2.1.2.RELEASE.jar:2.1.2.RELEASE]
at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:127) ~[spring-boot-test-2.1.2.RELEASE.jar:2.1.2.RELEASE]
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99) ~[spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117) ~[spring-test-5.1.4.RELEASE.jar:5.1.4.RELEASE]
... 28 common frames omitted
Caused by: java.lang.NullPointerException: null
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processFkSecondPassesInOrder(InFlightMetadataCollectorImpl.java:1749) ~[hibernate-core-5.3.7.Final.jar:5.3.7.Final]
at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1658) ~[hibernate-core-5.3.7.Final.jar:5.3.7.Final]
at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:287) ~[hibernate-core-5.3.7.Final.jar:5.3.7.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:904) ~[hibernate-core-5.3.7.Final.jar:5.3.7.Final]
at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:935) ~[hibernate-core-5.3.7.Final.jar:5.3.7.Final]
at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:57) ~[spring-orm-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:365) ~[spring-orm-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.buildNativeEntityManagerFactory(AbstractEntityManagerFactoryBean.java:390) ~[spring-orm-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:377) ~[spring-orm-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.afterPropertiesSet(LocalContainerEntityManagerFactoryBean.java:341) ~[spring-orm-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1804) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1741) ~[spring-beans-5.1.4.RELEASE.jar:5.1.4.RELEASE]
... 43 common frames omitted
在运行了几个"实体删除"-"编译"周期后，我能够找到问题：标有@ManyToOne的 LocalDate 字段
通常，会捕获此类错误并返回有用的错误消息，例如：
Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on com.entityClass.refereceDate references an unknown entity: java.time.LocalDate
这同样适用于其他对象，例如字符串：
Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on com.opsfactor.planning.model.domain.masterdata.production.RecursoProdutivoTeste.string references an unknown entity: java.lang.String
在我的例子中，该字段位于复合键内，因此结论是，当将@ManyToOne注释分配给嵌入式 Id 类中的整数、长整型、浮点型、LocalDate 或字符串字段时，Hibernate 不会指定错误的实体/字段。
该实体描述如下：
@Entity
public class TestClass{
@EmbeddedId
@NonNull // torna campo obrigatório e parâmetro do construtor gerado pelo @Data (lombok)
private TestCompositeKey testCompositeKey;
public static class TestCompositeKey implements Serializable {
@ManyToOne
private AnotherEntity anotherEntity;
@ManyToOne // (this line should be removed)
private LocalDate referenceDate;
}
}