我在 Eclipse 中设置一个使用纯 JPA 机制但使用 Hibernate 作为实现层的项目时遇到问题。
我有一个简单的程序,其中有 2 个类,通过多对多关系链接,所有类都使用注释定义。
我想避免使用 hibernate 特定配置,以便尽可能独立于数据库。例如,我希望所有配置都位于 persistence.xml 文件中。
每次启动程序时都会出现以下错误:
juil. 18, 2014 7:28:11 PM org.hibernate.ejb.HibernatePersistence logDeprecation
WARN: HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
juil. 18, 2014 7:28:11 PM org.hibernate.ejb.HibernatePersistence logDeprecation
WARN: HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
juil. 18, 2014 7:28:11 PM org.hibernate.ejb.HibernatePersistence logDeprecation
WARN: HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
juil. 18, 2014 7:28:11 PM org.hibernate.jpa.internal.util.LogHelper logPersistenceUnitInformation
INFO: HHH000204: Processing PersistenceUnitInfo [
name: Test-Cache-Hibernate
...]
juil. 18, 2014 7:28:11 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.3.5.Final}
juil. 18, 2014 7:28:11 PM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
juil. 18, 2014 7:28:11 PM org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
juil. 18, 2014 7:28:11 PM org.hibernate.annotations.common.reflection.java.JavaReflectionManager <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.4.Final}
Initial SessionFactory creation failed.javax.persistence.PersistenceException: Unable to build entity manager factory
上下文: eclipse 月神 JPA 2.1 hibernate 4.3.5
这是我的 persistence.xml :
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" xmlns="http://xmlns.jcp.org/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd">
<persistence-unit name="Test-Cache-Hibernate" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<non-jta-data-source>datasource</non-jta-data-source>
<shared-cache-mode>ENABLE_SELECTIVE</shared-cache-mode>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/testcache"/>
<property name="javax.persistence.jdbc.user" value="root"/>
<property name="javax.persistence.jdbc.password" value="admin"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
</properties>
</persistence-unit>
</persistence>
我在 Singleton 类中隔离了实体管理器的创建,如下所示:
package src.persistence.dbmanager;
import javax.persistence.EntityManager;
import javax.persistence.Persistence;
public class DBManager {
public static final EntityManager entityManager;
static {
try {
entityManager = Persistence.createEntityManagerFactory("Test-Cache-Hibernate").createEntityManager();
} catch (Throwable ex) {
throw new ExceptionInInitializerError(ex);
}
}
public static EntityManager getEntityManager() {
return entityManager;
}
}
当我使用以下方法手动将 EntityManager 注入(inject) DAO 对象时,出现上述错误:
private EntityManager entityManager = DBManager.getEntityManager();
编辑1: 这是我的 DAO 对象之一的代码:
package acs.testcache.persistence.dao;
import java.util.HashSet;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import acs.testcache.persistence.entities.MyChildObject;
import acs.testcache.persistence.entities.MyParentObject;
public class MyChildDAO extends MyCommonDAO<MyChildObject> {
@PersistenceContext(unitName="Test-Cache-Hibernate")
private EntityManager entityManager;
public MyChildDAO() {
super(MyChildObject.class);
}
public EntityManager getEntityManager() {
return entityManager;
}
@SuppressWarnings("unchecked")
public void getParents(MyChildObject c){
StringBuilder hqlQuery = new StringBuilder();
hqlQuery.append("select c.parentsObjects from MyChildObject c where c.id = :id");
Query q = getEntityManager().createQuery(hqlQuery.toString()).setParameter("id", c.getId()).setHint("org.hibernate.cacheable", true);
List<MyParentObject> result = q.getResultList();
c.setParents(new HashSet<MyParentObject>(result));
}
}
持久化管理器永远不会被注入(inject)。
当我尝试使用注释自动注入(inject)它时,查询时出现空指针异常。
有人可以帮忙吗?
谢谢。
最佳答案
请提供如何使用注释注入(inject)EntityManager
的代码。您是否尝试过像这样使用 @PersistenceContext
注释?
@PersistenceContext private EntityManager entityManager;
在这种情况下,使用 @Component
、@Resource
(或任何 Java 的 native 等效注释)将不起作用。
关于java - 如何设置 JPA 项目与 Hibernate 一起使用?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/24830932/