내 목표는 applicationContext.xml 파일에서 EntityManagerFactory를 인스턴스화하여 SQL 데이터베이스에 등록 된 모든 게시물을 가져 오는 것입니다. EntityManagerFactory를 사용할 때 NullPointerException이 발생했습니다.
public class PostDAO extends GenericDAOEntity<Post> implements IPostDAO
{
}
PostDAO.java
applicationContext.xml
<beans xmlns="http://www.springframework.org/schema/beans"
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"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<!-- Properties files linkers -->
<context:property-placeholder location="/WEB-INF/resources/database/jdbc.properties"/>
<context:property-placeholder location="/WEB-INF/resources/database/hibernate.properties"/>
<!-- Config database - initialization -->
<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" />
</bean>
<!-- Three main layers definition -->
<context:annotation-config />
<context:component-scan base-package="com.zone42"/>
<!-- Transaction sub-system initialization -->
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<tx:annotation-driven transaction-manager="transactionManager" />
</beans>
(WEB-INF가/클래스 /)
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="post-unit" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>com.zone42.model.Post</class>
<exclude-unlisted-classes>true</exclude-unlisted-classes>
</persistence-unit>
</persistence>
의 persistence.xml : 다음은 주요 파일의 내용입니다
GenericDAOEntity.java
@Transactional
public class GenericDAOEntity<T> implements IGenericDAO<T>
{
/**
* Properties
*/
@Autowired
@PersistenceContext(unitName="post-unit")
private EntityManagerFactory entityManagerFactory/* = Persistence.createEntityManagerFactory(persistence_unit_name)*/;
//Get all posts
@SuppressWarnings("unchecked")
public List<T> findAll(Class<T> obj) {
EntityManager entityManager = this.entityManagerFactory.createEntityManager();
Query query = entityManager.createQuery("from " + obj.getSimpleName());
return (query.getResultList());
}
/**
* Accessors
*/
public EntityManagerFactory getEntityManagerFactory() {
return entityManagerFactory;
}
@PersistenceContext(unitName="post-unit")
public void setEntityManagerFactory(EntityManagerFactory entityManagerFactory) {
this.entityManagerFactory = entityManagerFactory;
}
}
몇 가지 구성 조합을 시도했지만 성공하지 못했습니다. NullPointerException
은 엔티티 팩토리 인스턴스에서 EntityManager의 인스턴스를 만들 때 findAll
메서드에서 가져온 것입니다. 구성 문제가 있다고 생각합니다. 정확한 코드가 작동하려면 EntityManagerFactory를 클래스에서 직접 new 연산자를 사용하여 인스턴스화해야합니다. 이제는 appicationContext.xml 파일에서 xml을 사용하는 다른 방법을 선택하여 내 공장을 할당하려고합니다. 누구든지 나를 도울 수 있습니까? 미리 감사드립니다.
를? –