Question

我正在开发一个使用datanucleus作为JPA的WebApp - Provider和Neo4j作为No-SQL数据库。

我的依赖是

   <dependency>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-core</artifactId>
        <version>[5.0.0-m1, 5.9)</version>
    </dependency>
    <dependency>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-api-jpa</artifactId>
        <version>[5.0.0-m1, 5.9)</version>
    </dependency>
    <dependency>
        <groupId>org.datanucleus</groupId>
        <artifactId>javax.persistence</artifactId>
        <version>2.1.0</version>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>[1.2, 1.3)</version>
    </dependency>

   <dependency>
        <groupId>org.datanucleus</groupId>
        <artifactId>datanucleus-neo4j</artifactId>
        <version>[5.0.0-m1, 5.9)</version>
    </dependency>
    <dependency>
        <groupId>org.neo4j</groupId>
        <artifactId>neo4j</artifactId>
        <version>2.3.0</version>
    </dependency>

我的persistence.xml看起来像

<persistence-unit name="neo4j">
 <provider>org.datanucleus.api.jpa.PersistenceProviderImpl</provider>
 <class>entities.Person</class>
 <class>entities.Car</class>
    <exclude-unlisted-classes/>
    <properties>
        <property name="javax.persistence.jdbc.url" value="neo4j:C:\Users\phe\Documents\Neo4j\sampledatanucleus"/>
        <!-- <property name="datanucleus.storeManagerType" value="neo4j"/> -->
        <property name="datanucleus.storeManagerType" value="neo4j"/>
    </properties>
</persistence-unit>

我坚持这样的实体

        Person person = new Person(personName, personAge);
        Car car = new Car(carName);
        car.setOwner(person);
        person.getCars().add(car);
        em.persist(person);

当持久化实体时，我得到一个例外：

Caused by: org.neo4j.kernel.StoreLockException: Unable to obtain lock on store lock file: C:\Users\phe\Documents\Neo4j\sampledatanucleus\store_lock. Please ensure no other process is using this database, and that the directory is writable (required even for read-only access)
at org.neo4j.kernel.StoreLocker.storeLockException(StoreLocker.java:93)
at org.neo4j.kernel.StoreLocker.checkLock(StoreLocker.java:85)
at org.neo4j.kernel.StoreLockerLifecycleAdapter.start(StoreLockerLifecycleAdapter.java:44)
at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:528)
... 153 more

这让我发疯了。当我启动应用程序时，我在perstistence.xml中定义的目录为空。因此，它不可能被另一个进程锁定。然后DataNucleus创建数据库。我可以使用Neo4j Browser访问它。但坚持不起作用。

有什么想法吗？

修改

这是我用来查询的类

@Stateless
public class Manager {

  @PersistenceContext(unitName = "neo4j")
  private EntityManager em;

  public List<Person> queryCache() {
    String statement = "Select o from Person o";
    Query query = em.createQuery(statement, Person.class);
    List<Person> list = query.getResultList();
    em.close();
    return list;
  }

  public void save(String personName, Double personAge, String carName) {

    Person person = new Person(personName, personAge);
    Car car = new Car(carName);
    car.setOwner(person);
    person.getCars().add(car);
    em.persist(person);
  }
}

当单击视图上的相应按钮时，控制器会调用这两个方法。

datanucleus neo4j - 无法获取商店锁定文件的锁定

0 个答案: