如何使用spring + JPA

將不同的實體管理器工廠注入到相同的DAO中我試圖將兩個不同的EntityManagerFactory實例注入到同一個DAO中。我在一個項目中有一個通用的DAO，我們稱之爲「Project Base」，並且我有兩個不同的項目，即項目A和項目B.持久單元在Project Base中定義。如何使用spring + JPA

我的問題是，我希望能夠給EntityManagerFactory實例注入到DAO，而不是使用@PersistenceUnit因爲我有兩個不同的數據庫，其中一個是被項目A和另一個由項目B.

我的只有在通用DAO的基本CRUD操作，但春天給了我以下異常：

Error creating bean with name 'genericHibernateDAO': Injection of persistence dependencies failed; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [javax.persistence.EntityManagerFactory] is defined: expected single bean but found 2

請在下面找到我的配置：

<beans xmlns="http://www.springframework.org/schema/beans" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" 
    xsi:schemaLocation=" 
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd 
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd" 
    default-autowire="autodetect"> 
    <context:component-scan base-package="com.entertainment" /> 


    <!-- Entity Manager --> 
    <bean id="abstractEntityManagerFactory" 
     class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" abstract="true"> 
     <property name="jpaVendorAdapter" ref="jpaVendorAdapter" /> 
     <property name="dataSource" ref="ADataSource" /> 
    </bean> 


    <bean id="AEntityManagerFactory" parent="abstractEntityManagerFactory"> 
     <property name="persistenceUnitName" value="A" /> 
    </bean> 

    <bean id="BEntityManagerFactory" parent="abstractEntityManagerFactory"> 
     <property name="persistenceUnitName" value="B" /> 
    </bean> 


    <!-- Datasource --> 
    <bean id="ADataSource" 
     class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 
     <property name="driverClassName" value="oracle.jdbc.OracleDriver" /> 
     <property name="url" 
      value="myUrl" /> 
     <property name="username" value="username" /> 
     <property name="password" value="password" /> 
    </bean> 

    <bean id="BDataSource" 
     class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 
     <property name="driverClassName" value="oracle.jdbc.OracleDriver" /> 
     <property name="url" 
      value="myUrl" /> 
     <property name="username" value="username" /> 
     <property name="password" value="password" /> 
    </bean> 


    <!-- Transaction Manager --> 
    <bean id="ATransactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> 
     <property name="entityManagerFactory" ref="entityManagerFactory" /> 
    </bean> 


    <bean id="BTransactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> 
     <property name="entityManagerFactory" ref="entityManagerFactory" /> 
    </bean> 

    <!-- Vendor adapter --> 
    <bean id="jpaVendorAdapter" 
     class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> 
     <property name="databasePlatform" value="org.hibernate.dialect.Oracle9iDialect" /> 
     <property name="showSql" value="true" /> 
     <property name="generateDdl" value="true" /> 
    </bean> 

    <!-- generic DAO --> 

    <bean id="genericDAO" 
     class="mypackage.GenericHibernateDAO" abstract="true"/> 


</beans>

此文件是在項目基地：

<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 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="A" transaction-type="RESOURCE_LOCAL"> 
     <provider>org.hibernate.ejb.HibernatePersistence</provider> 
     <properties> 
      <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle9Dialect" /> 
      <property name="hibernate.connection.driver_class" value="oracle.jdbc.OracleDriver" /> 
      <property name="hibernate.show_sql" value="true" /> 
      <property name="hibernate.connection.username" value="username" /> 
      <property name="hibernate.connection.password" value="password" /> 
      <property name="hibernate.connection.url" value="myurl" /> 
      <property name="hibernate.max_fetch_depth" value="3" /> 
      <property name="hibernate.archive.autodetection" value="class" /> 
     </properties> 
    </persistence-unit> 
    <persistence-unit name="B" transaction-type="RESOURCE_LOCAL"> 
     <provider>org.hibernate.ejb.HibernatePersistence</provider> 
     <properties> 
      <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle9Dialect" /> 
      <property name="hibernate.connection.driver_class" value="oracle.jdbc.OracleDriver" /> 
      <property name="hibernate.show_sql" value="true" /> 
      <property name="hibernate.connection.username" value="username" /> 
      <property name="hibernate.connection.password" value="password" /> 
      <property name="hibernate.connection.url" value="myurl" /> 
      <property name="hibernate.max_fetch_depth" value="3" /> 
      <property name="hibernate.archive.autodetection" value="class" /> 
     </properties> 
    </persistence-unit> 
</persistence>

我一直真的努力摸不着頭腦。我會很感激任何幫助。

在此先感謝！

來源

2012-04-23 user1260109

您是否嘗試過使用@PersistenceUnit.unitName配置持久性單元？

來源

2013-10-07 16:41:37 Vincent

@PersistenceUnit(unitName="A") 
EntityManagerFactory entityMgrFactory;

OR（這將注入EMFactory有關persistenceUnit A）

@Autowired 
@Qualified("AEntityManagerFactory") 
private EntityManagerFactory AEntityManagerFactory;

@PersistenceContext(unitName="A") 
EntityManager em;

沒有的unitName總是期望只有一個EMFactory，當你有兩個，春天不要不知道哪個通行證。

來源

2014-01-31 07:52:51 Koitoer

如何使用spring + JPA

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