Question

所以我开始使用Spring Data JPA，我发现它最初很容易使用，特别是对于简单的POJO实体，我设法用单个实体（Person）执行简单的CRUD操作，但是当我深入挖掘我的设计时（继承），在继承设计方面，我开始很难处理Spring JPA存储库。

传奇：

的POJO

存储库

使用上述两个

的示例类

抛出异常

xml配置

人类（基础，抽象类）

 @MappedSuperclass
 public abstract class Person {
       ..properties, getters and setters with hibernate annotations
}

学生班（孩子，延伸人）

 @Entity
 @Table(name = "STUDENT")
 public class Student extends Person {
        .. properties, getters and setters SPECIFIC for a student
 }

贮库

PersonRepository （基础，父存储库）

 public interface PersonRepository<T extends Person, ID extends Serializable> extends JpaRepository<T, ID> {
 }

StudentRepository （child，extends PersonRepository）

 public interface StudentRepository extends PersonRepository<Student, Integer>{
 }

示例类

 @Service ("manager")
  public class Manager {

  @SuppressWarnings("rawtypes")
  @Resource (name = "personRepository")
  private PersonRepository personRepository;

  @SuppressWarnings("unchecked")
  public void savePerson(Person p) {

      personRepository.save(p);
  }
}

抛出异常

线程中的异常＆＃34; main＆＃34; org.springframework.beans.factory.BeanCreationException：使用名称＆＃39; manager＆＃39;创建bean时出错：资源依赖注入失败;嵌套异常是org.springframework.beans.factory.BeanCreationException：创建名为＆＃39; personRepository＆＃39;：FactoryBean的bean在创建对象时引发异常;嵌套异常是java.lang.NullPointerException at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues（CommonAnnotationBeanPostProcessor.java:308）在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean（AbstractAutowireCapableBeanFactory.java:1185）在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean（AbstractAutowireCapableBeanFactory.java:537）在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean（AbstractAutowireCapableBeanFactory.java:475）在org.springframework.beans.factory.support.AbstractBeanFactory $ 1.getObject（AbstractBeanFactory.java:302）在org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton（DefaultSingletonBeanRegistry.java:228）在org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean（AbstractBeanFactory.java:298）在org.springframework.beans.factory.support.AbstractBeanFactory.getBean（AbstractBeanFactory.java:193） at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons（DefaultListableBeanFactory.java:703）在org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization（AbstractApplicationContext.java:760） at org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:482）在org.springframework.context.support.ClassPathXmlApplicationContext。（ClassPathXmlApplicationContext.java:139）在org.springframework.context.support.ClassPathXmlApplicationContext。（ClassPathXmlApplicationContext.java:83）在edu.main.Main.main（Main.java:12）引起：org.springframework.beans.factory.BeanCreationException：创建名称为＆＃39; personRepository＆＃39;：FactoryBean的bean在创建对象时引发异常;嵌套异常是java.lang.NullPointerException 在org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean（FactoryBeanRegistrySupport.java:175）在org.springframework.beans.factory.support.FactoryBeanRegistrySupport.getObjectFromFactoryBean（FactoryBeanRegistrySupport.java:103）在org.springframework.beans.factory.support.AbstractBeanFactory.getObjectForBeanInstance（AbstractBeanFactory.java:1512）在org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean（AbstractBeanFactory.java:313）在org.springframework.beans.factory.support.AbstractBeanFactory.getBean（AbstractBeanFactory.java:198） at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource（CommonAnnotationBeanPostProcessor.java:446）在org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource（CommonAnnotationBeanPostProcessor.java:420） at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor $ ResourceElement.getResourceToInject（CommonAnnotationBeanPostProcessor.java:545）在org.springframework.beans.factory.annotation.InjectionMetadata $ InjectedElement.inject（InjectionMetadata.java:155）在org.springframework.beans.factory.annotation.InjectionMetadata.inject（InjectionMetadata.java:87）在org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues（CommonAnnotationBeanPostProcessor.java:305） ......还有13个引起：java.lang.NullPointerException at java.lang.Class.isAssignableFrom（Native Method）在org.springframework.data.jpa.repository.support.JpaEntityInformationSupport.getMetadata(JpaEntityInformationSupport.java:58）在org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getEntityInformation（JpaRepositoryFactory.java:145）在org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository（JpaRepositoryFactory.java:83）在org.springframework.data.jpa.repository.support.JpaRepositoryFactory.getTargetRepository（JpaRepositoryFactory.java:66）在org.springframework.data.repository.core.support.RepositoryFactorySupport.getRepository（RepositoryFactorySupport.java:146）在org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.getObject（RepositoryFactoryBeanSupport.java:120）在org.springframework.data.repository.core.support.RepositoryFactoryBeanSupport.getObject（RepositoryFactoryBeanSupport.java:39）在org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean（FactoryBeanRegistrySupport.java:168）

xml配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:repository="http://www.springframework.org/schema/data/repository"
xmlns:jpa="http://www.springframework.org/schema/data/jpa"         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:tx="http://www.springframework.org/schema/tx"             xmlns:context="http://www.springframework.org/schema/context"
 xsi:schemaLocation="http://www.springframework.org/schema/beans 
     http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
     http://www.springframework.org/schema/context  
     http://www.springframework.org/schema/context/spring-context-4.0.xsd
     http://www.springframework.org/schema/tx 
     http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
     http://www.springframework.org/schema/data/repository
     http://www.springframework.org/schema/data/repository/spring-repository.xsd
     http://www.springframework.org/schema/data/jpa 
     http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">


<context:annotation-config />
<context:component-scan base-package="edu.service" />
<jpa:repositories base-package="edu.repository" />
<tx:annotation-driven />

<context:property-placeholder
    location="classpath:properties/database.properties"
    ignore-unresolvable="false" />

<bean id="dataSource"
    class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="${jdbc.driverClassName}" />
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />
</bean>

<bean id="entityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <property name="packagesToScan">
        <list>
            <value>edu.domain</value>
        </list>
    </property>
    <property name="persistenceUnitName" value="personPU"/>
    <property name="jpaVendorAdapter">
        <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
    </property>
    <property name="jpaProperties">
        <props>
            <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
            <prop key="hibernate.show_sql">false</prop>
        </props>
    </property>
</bean>

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

我试图找到一个特定的单词来搜索类似的问题，但没有运气，可能导致我的存储库没有存储库bean的问题（NullPointerException / BeanCreationException）？还有一件事我想补充一下，我的设计模式有问题吗？我应该将我的POJO继承模式反映到我的存储库吗？我试图让我的PersonRepository在作为Person类（抽象父类）的子节点的POJO / Entites上执行操作，这就是为什么我想出了存储库继承的想法。我的具体目标是，对使用PersonRepository扩展Person的任何对象持久/执行CRUD。非常感谢任何帮助/建议/意见。请。非常感谢你

Answer 1

我认为PersonRepository应注明@NoRepositoryBean。

在我的申请中，我这样做了：

父：

@NoRepositoryBean
public interface UserRepository<T> extends JpaRepository<T, Long> {
}

子：

@Repository
public interface EmployeeRepository extends UserRepository<Employee> {
}

希望它有所帮助。

Spring Data JPA。存储库继承，抛出BeanCreationException，NullPointerException

1 个答案: