java - 配置 Play 2 以使用 JPA 运行时出现问题(持久性)

Question

尝试保存数据时出现以下错误:

[PersistenceException: [PersistenceUnit: update] class or package not found]
In C:\Users\Johann\Desktop\SODET\play-2.1.1\todolist\app\models\Stream.java at line 32.



32                EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("update");

这是Stream.java(模型)

package models;

import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Id;
import javax.persistence.Persistence;

import com.restfb.Facebook;

@Entity
public class Stream {
      @Facebook
      @Id
      public String post_id;

      @Facebook
      public String created_time;

      @Facebook
      public String message;

      @Facebook
      public String permalink;

      @Override
      public String toString() {
        return String.format("%s, %s, %s, %s", created_time, message, permalink, post_id);
      }

      public void save(){
          EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("update");
          EntityManager entityManager = entityManagerFactory.createEntityManager();
          entityManager.getTransaction().begin();
          entityManager.persist(this);      
          entityManager.getTransaction().commit();
          entityManager.close();
      }

}

persistence.xml 文件位于conf/META-INF 目录中:

<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="update" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>

        <non-jta-data-source>DefaultDS</non-jta-data-source>

        <class>models.Stream</class>
        <class>models.FacebookUser</class>
        <class>models.Comment</class>
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>
        </properties>
    </persistence-unit>

</persistence>

这是Build.scala

import sbt._
import Keys._
import play.Project._

object ApplicationBuild extends Build {

  val appName         = "todolist"
  val appVersion      = "1.0-SNAPSHOT"

  val appDependencies = Seq(
    // Add your project dependencies here,
    "com.restfb" % "restfb" % "1.6.11",
    "mysql" % "mysql-connector-java" % "5.1.25",
    "org.hibernate" % "hibernate-entitymanager" % "4.2.1.Final",
    javaCore,
    javaJdbc,
    javaJpa
  )

  val main = play.Project(appName, appVersion, appDependencies).settings(
    // Add your own project settings here      
  )

}

我查看了文档，但没有发现任何相关内容......

提前致谢!

Answer 1

注意您的 application.conf 中的名称与 update 不同:示例:

jpa.update=updatePersistenceUnit

我认为您没有应用程序必须在 application.conf 和 hibernate 文件中匹配的这一行

注意:hbm2dll 中的值更新仅用于在模型发生更改时更新数据库架构。我认为你必须使用 defaultPersistentUnit 名称，因为在 application.conf 中它可能是这样的:

jpa.default=defaultPersistenUnit

然后

db.default.driver=您的驱动程序db.defalut.url=您的网址