Question

我正在尝试按照Hibernate EntityManager documentation中的信息设置一个简单的jpa 2.0项目。我已经在这几个小时了，但不管我做什么，当我尝试创建一个EntityManagerFactory时，我总是得到这个例外：

Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named manager1
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:32)
    at se.mycomp.UserTest.main(UserTest.java:9)

我发现了很多关于这个例外的类似问题，但没有解决方案我可以开始工作。我在这里做错了什么？

目录结构

.
├── pom.xml
└── src
    ├── main
    │   ├── java
    │   │   └── se
    │   │       └── mycomp
    │   │           ├── UserTest.java
    │   │           └── domain
    │   │               └── User.java
    │   └── resources
    │       ├── META-INF
    │       │   └── persistence.xml
    │       └── log4j.properties
    └── test
        └── java

我的 persistence.xml

<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="manager1" transaction-type="RESOURCE_LOCAL">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <class>se.mycomp.domain.User</class> 
        <properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect"/>
            <property name="hibernate.hbm2ddl.auto" value="create-drop"/>

            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost/test"/>
            <property name="javax.persistence.jdbc.user" value="test"/>
            <property name="javax.persistence.jdbc.password" value="1234"/>
        </properties>
    </persistence-unit>
</persistence>

我的 pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>se.lil.tryjpa</groupId>
<artifactId>try-jpa</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

    <hibernate-core.version>3.6.4.Final</hibernate-core.version>
    <mysql-connector-java.version>5.1.16</mysql-connector-java.version>
    <slf4j.version>1.6.1</slf4j.version>
    <log4j.version>1.6.1</log4j.version>
</properties>

<dependencies>
    <!-- HIBERNATE DEPENDENCIES -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>${hibernate-core.version}</version>
    </dependency>

    <!-- MYSQL DEPENDENCIES -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql-connector-java.version}</version>
    </dependency>

    <!-- Logging Dependencies -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${slf4j.version}</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>${log4j.version}</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <optimize>true</optimize>
                <debug>true</debug>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-eclipse-plugin</artifactId>
            <version>2.8</version>
            <configuration>
                <downloadSources>true</downloadSources>
            </configuration>
        </plugin>
    </plugins>
</build>

的 UserTest.java 的

public class UserTest {
    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("manager1");
        EntityManager em = emf.createEntityManager();
    }
}

Answer 1

也许您错过了您的pom.xml依赖项中的Provider类或其依赖项之一？

您提供给hibernate文档的链接表示您还应添加

<project ...>
  ...
  <dependencies>
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-entitymanager</artifactId>
      <version>${hibernate-core-version}</version>
    </dependency>
  </dependencies>
</project>

到你的pom.xml

Answer 2

persistence.xml意味着存在于META-INF目录中，而META-INF意味着存在于应用程序的类路径中，即src文件夹。

根据你的文件夹结构，它存在于资源文件夹中，尝试将其移动到类路径，它会影响工作。

Answer 3

我使用下面的依赖项和以下提供程序解决了这个问题：

<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>


 <dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>9.4-1200-jdbc41</version>
</dependency>
<dependency>
    <groupId>org.hibernate.javax.persistence</groupId>
    <artifactId>hibernate-jpa-2.0-api</artifactId>
    <version>LATEST</version>
</dependency>
<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-entitymanager</artifactId>
    <version>LATEST</version>
</dependency>

最新版本不适用于您，您可以使用 1.0.1.Final为hibernate-jpa-2.0-api 和5.2.5.Final for hibernate-entitymanager

另外，在persistence.xml中，不要忘记hbm2dll.auto属性（这是我花了一些时间搞清楚的问题）

<property name="hibernate.hbm2ddl.auto" value="create"/>
<property name="hibernate.show_sql" value="true"/>

然后进行maven clean install

JPA 2.0使用Hibernate作为提供程序 - 例外：没有EntityManager的持久性提供程序

3 个答案: