没有EntityManager的持久性提供者命名为...错误 [英] No Persistence provider for EntityManager named... error

问题描述

我的持久xml文件就是这样

 <？xml version =1.0encoding =UTF-8 ？> 
< 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_1_0.xsd
 version = 1.0 > 
< persistence-unit name =hibernateEbru> 
< provider> org.hibernate.ejb.HibernatePersistence< / provider> 
< class> com.hibernate.business_card< / class> 
<属性> 
< property name =hibernate.hbm2ddl.autovalue =create/> 
< property name =hibernate.show_sqlvalue =true/> 
< property name =hibernate.dialectvalue =org.hibernate.dialect.MySQL5InnoDBDialect/> 
< property name =hibernate.connection.driver_classvalue =com.mysql.jdbc.Driver/> 
< property name =hibernate.connection.usernamevalue =root/> 
< property name =hibernate.connection.passwordvalue =2643/> 
< property name =hibernate.connection.urlvalue =jdbc：mysql：// localhost：3306 / BusinessDb/> 
 
< / properties> 
< / persistence-unit> 
< /余辉> 
  

然后我用我的代码调用它：

  public class test {
 public static void main（String [] args）{
 EntityManagerFactory emf = Persistence.createEntityManagerFactory（hibernateEbru）; 
 
 EntityManager em = emf.createEntityManager（）; 
 
 em.getTransaction（）。begin（）; 
 
 business_card bc = new business_card（）; 
 bc.setName（Ebru）; 
 
 em.persist（bc）; 
 
 em.getTransaction（）。commit（）; 
 
 em.close（）; 
 
 emf.close（）; 
 
 
 
 
 
我得到以下错误信息： 
 线程main中的异常javax.persistence.PersistenceException：否在EntityManager中的名称为hibernateEbru 
的持久性提供程序。 persistence.Persistence.createEntityManagerFactory（Persistence.java:56）
 at javax.persistence.Persistence.createEntityManagerFactory（Persistence.java:34）
 at com.hibernate.test.main（test.java:8） 
  
 
 
解决方案
您需要将persistence.xml文件移至一个合适的位置
 
 
 
来自JPA规范： 
 
 
 一个persistence.xml文件定义了一个持久性单元。 persistence.xml文件是位于持久性单元根目录的META-INF目录中的
。 
  
持久单元的根是这里的关键。 
 
 
 
如果您是非Java EE应用程序
 其META-INF目录包含persistence.xml 
文件的文件或目录称为持久性单元的根。 
  
如果您在Java EE应用程序中，以下内容有效
 在Java EE环境中，持久性单元的根必须是下列之一：
•一个EJB-JAR文件
• WAR文件的WEB-INF / classes目录[80] 
•WAR文件的WEB-INF / lib目录中的jar文件
•EAR库目录中的jar文件
 •应用程序客户端jar文件
  
 
My persistence xml file is like that 
<?xml version="1.0" encoding="UTF-8"?>
<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_1_0.xsd"
    version="1.0">
    <persistence-unit name="hibernateEbru">     
        <provider>org.hibernate.ejb.HibernatePersistence</provider>     
        <class>com.hibernate.business_card</class> 
        <properties>            
            <property name="hibernate.hbm2ddl.auto" value="create" />           
            <property name="hibernate.show_sql" value="true" />         
            <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />         
            <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />         
            <property name="hibernate.connection.username" value="root" />          
            <property name="hibernate.connection.password" value="2643" />          
            <property name="hibernate.connection.url" value="jdbc:mysql://localhost:3306/BusinessDb" /> 

        </properties>
    </persistence-unit>
</persistence>
Then I have my code calling it with this:
public class test {
    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("hibernateEbru");

        EntityManager em = emf.createEntityManager();

        em.getTransaction().begin();

        business_card bc = new business_card();
        bc.setName("Ebru");

        em.persist(bc);

        em.getTransaction().commit();

        em.close();

        emf.close();

    }
}
I got the following error message:
Exception in thread "main" javax.persistence.PersistenceException: No Persistence provider for EntityManager named hibernateEbru
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:56)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:34)
    at com.hibernate.test.main(test.java:8)

解决方案
You will need to move the persistence.xml file to an appropriate location

From JPA spec:
A persistence.xml file defines a persistence unit. The persistence.xml file is 
located in the META-INF directory of the root of the persistence unit. 
The root of the persistence unit is the key here. 

If you are a non-Java EE app 
The jar file or directory whose META-INF directory contains the persistence.xml 
file is termed the root of the persistence unit.
If you are in a Java EE app, the following are valid
In Java EE environments, the root of a persistence unit must be one of the following:
• an EJB-JAR file
• the WEB-INF/classes directory of a WAR file[80]
• a jar file in the WEB-INF/lib directory of a WAR file
• a jar file in the EAR library directory
• an application client jar file


                        
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