Spring Boot：创建名为“jpaMappingContext”的 bean 时出错：java.lang.NullPointerException

Spring Boot : Error creating bean with name 'jpaMappingContext': java.lang.NullPointerException

提问by Sudhirkd

My combination of is Spring Boot + Spring Data Jpa + Multiple Databases. I am getting following NullPointer exception when starting the application. Feels like SPring Data with Boot is not able to generate JPA Metadata. I did not get any resource related to this error.

我的组合是 Spring Boot + Spring Data Jpa + Multiple Databases。启动应用程序时，我遇到了 NullPointer 异常。感觉像带启动的 SPring 数据无法生成 JPA 元数据。我没有得到与此错误相关的任何资源。

Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'jpaMappingContext': Invocation of init method failed; nested exception is java.lang.NullPointerException
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:303)
        at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
        at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
        at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
        at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:736)
        at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118)
        at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:686)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:957)
        at org.springframework.boot.SpringApplication.run(SpringApplication.java:946)
        at com.verient.infinipay.staticcard.Application.main(Application.java:25)
        ... 6 more
Caused by: java.lang.NullPointerException
        at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.getMetamodels(JpaMetamodelMappingContextFactoryBean.java:90)
        at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:56)
        at org.springframework.data.jpa.repository.config.JpaMetamodelMappingContextFactoryBean.createInstance(JpaMetamodelMappingContextFactoryBean.java:26)
        at org.springframework.beans.factory.config.AbstractFactoryBean.afterPropertiesSet(AbstractFactoryBean.java:134)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1633)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570)
        ... 21 more

My Code is :

我的代码是：

    public EntityManagerFactory apEntityManagerFactory(
            EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(apDataSource())
                .packages(Entity1.class, Entity2.class)
                .persistenceUnit("ap-persistent-unit")
                .build()
                .getObject();
    }

    @Bean
    public EntityManagerFactory trEntityManagerFactory(
            EntityManagerFactoryBuilder builder) {
        return builder
                .dataSource(trDataSource())
                .packages(Entity3.class, Entity4.class)
                .persistenceUnit("tr-persistent-unit")
                .build()
                .getObject();
    }

    @Bean
    JpaTransactionManager apTransactionManager(@Qualifier("apEntityManagerFactory") EntityManagerFactory entityManagerFactory) {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory);
        return transactionManager;
    }

    @Bean
    JpaTransactionManager trTransactionManager(@Qualifier("trEntityManagerFactory") EntityManagerFactory entityManagerFactory) {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory);
        return transactionManager;
    }

I also have following hibernate properties in application.properties.

我在 application.properties 中也有以下休眠属性。

spring.jpa.hibernate.ddl-auto: update
spring.jpa.hibernate.naming_strategy: org.hibernate.cfg.ImprovedNamingStrategy
spring.jpa.database: H2
spring.jpa.show-sql: true

回答by wallance

Spring boot have AutoConfiguration classes enabled by default for the data sources allready on classpath. You should explicitly exclude AutoConfiguration class to disable.

Spring Boot 默认为类路径上的数据源启用 AutoConfiguration 类。您应该明确排除要禁用的 AutoConfiguration 类。

Example :

例子 ：

@EnableAutoConfiguration(exclude = {JndiConnectionFactoryAutoConfiguration.class,DataSourceAutoConfiguration.class,
                                    HibernateJpaAutoConfiguration.class,JpaRepositoriesAutoConfiguration.class,DataSourceTransactionManagerAutoConfiguration.class})
@ComponentScan
public class MyBootApplication {
    public static void main(String[] args) {
        SpringApplication.run(MyBootApplication.class, args);
    }
}

回答by Vishal

For me this turned out to be due to a custom implementation of org.hibernate.usertype.UserTypethat I was using for mapping JSON types to Java objects.

对我来说，这是由于org.hibernate.usertype.UserType我用于将 JSON 类型映射到 Java 对象的自定义实现 。

In my particular case, it was mapping to a java.util.Map and this change in Spring Data JPAwas causing a regression on upgrading to that version.

在我的特定情况下，它映射到 java.util.Map 并且Spring Data JPA中的这种更改导致升级到该版本的回归。

The fix was to explicitly set generic types for the Map - e.g. Map<String, Object>in my case.

解决方法是为 Map 显式设置泛型类型 - 例如Map<String, Object>在我的情况下。

回答by IhorP

Many thanks to Vishal for the idea. In my case it was generic-less implementation of javax.persistence.AttributeConverterthat provoked this exception. Changing class MapConverter implements AttributeConverter<Map, String> { ... }to class MapConverter implements AttributeConverter<Map<String, Object>, String> { ... }really helped.

非常感谢 Vishal 的想法。在我的情况下，这是javax.persistence.AttributeConverter引发此异常的无泛型实现。更改 class MapConverter implements AttributeConverter<Map, String> { ... }为class MapConverter implements AttributeConverter<Map<String, Object>, String> { ... }确实有帮助。