我正试图完成一个使用RMI将工作负载发送到少数远程服务器的原型。工作完成后,远程服务器应该将结果写回数据库。我使用Hibernate作为提供者的JPA。但是我现在很难问远程服务器这样做。通过RMI启动远程服务器中的JPA EntityManagerFactory
这里是该部分代码是要通过RMI被发送到远程服务器
public class UpdateDB implements ServerRun<Boolean>, Serializable {
private static final long serialVersionUID = 2683781993159094346L;
@Override
public Boolean execute() {
EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("abc");
EntityManager entityManager = entityManagerFactory.createEntityManager();
entityManager.getTransaction().begin();
entityManager.persist(new User("First user!", new Date()));
entityManager.persist(new User("Second user", new Date()));
entityManager.getTransaction().commit();
entityManager.close();
entityManager.close();
entityManagerFactory.close();
return true;
}
}
这里是在上面的代码的相同的水平的资源/ META-INF persistence.xml中:
<persistence 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"
version="2.0">
<persistence-unit name="abc" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>data.persist.User</class>
<properties>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://192.168.205.103:3306/event_grp" />
<property name="javax.persistence.jdbc.user" value="username" />
<property name="javax.persistence.jdbc.password" value="password" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.hbm2ddl.auto" value="create" />
</properties>
</persistence-unit>
如果我它工作在服务器上运行的JPA,和别的作品中的RMI功能方面。但EntityManagerFactory的将无法启动,这里是错误:
Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named abc
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:69)
at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:47)
at data.persist.UpdateDB.execute(UpdateDB.java:58)
at data.persist.UpdateDB.execute(UpdateDB.java:1)
at engine.ComputeEngine.executeTask(ComputeEngine.java:39)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:303)
at sun.rmi.transport.Transport$1.run(Transport.java:159)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown Source)
at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
at sun.rmi.server.UnicastRef.invoke(Unknown Source)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source)
at com.sun.proxy.$Proxy12.executeTask(Unknown Source)
at client.JobSubmitter.main(JobSubmitter.java:94)
因此,它似乎是RMI不能找到或在META-INF加载的persistence.xml。我也有类似的经验与log4j,但我通过定义代码中的所有内容而不是使用log4j.properties文件。
编辑: 的代码将被发送到远程服务器的包装看起来,这是我放置persistence.xml中唯一的地方:
-src/main/java/data/persist/UpdataDB.java
|
src/main/resources/META-INF/persistence.xml
每user1888440的问题,我把安全权限配置在这里。与客户端和远程服务器使用以下权限:
grant {
permission java.security.AllPermission;
};
我怎样才能让远程服务器初始化的EntityManagerFactory,因此可以写回数据库?如果您可以提供一些简单的代码,我将非常感激。
我看不出这与RMI有什么关系。它关于您的持久性配置。 – EJP
它可以在本地机器上持久工作。它通过RMI发送到远程服务器时不起作用。如果这对您有意义,请添加RMI标签。 –