Spring - PersistenceContext - 没有事务性EntityManager可用

我正在使用带有JPA的 spring ，我的所有吸气剂都在工作 . 我可以从数据库中获取对象，但是当我尝试保存某些内容时，我收到错误“没有事务性EntityManager可用”，并且我有交易注释 .

这是我的DAO：

@Repository("userDao")
    @Transactional
    //public class UserDaoImpl extends GenericDaoImpl<User, Long> implements IUserDao {
    public class UserDaoImpl implements IUserDao {  

        final protected Logger logger = LoggerFactory.getLogger(this.getClass());

        public UserDaoImpl() {
        }

        @PersistenceContext(unitName = "ovdigitalPU")
        protected EntityManager entityManager;

    @Override
        @Transactional(readOnly = false, propagation = Propagation.REQUIRED)
        public void save(User user) throws DuplicatedUserException {
            logger.info("Creating User with username: " + user.getUsername());
            User foundUser = null;
            logger.info("Checking if user already existis...");
            /*foundUser = this.findByUsername(user.getUsername());

            if(foundUser != null) {
                throw new DuplicatedUserException();
            }*/

            entityManager.persist(user);
            logger.info("User " + user.getUsername() + " was been saved with success!");

        }

这是我的root-context.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
        xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/aop 
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
http://www.springframework.org/schema/mvc 
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/context 
http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <!-- Root Context: defines shared resources visible to all other web components -->
    <context:annotation-config />

    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/" />
        <property name="suffix" value=".jsp" />
    </bean>

    <bean id="ovdigitalDS"
        class="org.apache.commons.dbcp.BasicDataSource"
        p:driverClassName="com.mysql.jdbc.Driver" p:url="jdbc:mysql://localhost/ovdigital"
        p:username="ovdigital" p:password="12345">
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="ovdigitalDS" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
        </property>
    </bean>

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

    <tx:annotation-driven transaction-manager="transactionManager" />
    <context:spring-configured />
    <context:annotation-config />

</beans>

我的persistence.xml：

<?xml version="1.0" encoding="UTF-8"?>
    <persistence version="2.0" 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">
      <persistence-unit name="ovdigitalPU">
        <provider>org.hibernate.ejb.HibernatePersistence</provider>
        <properties>
          <property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect"/>
          <property name="hibernate.transaction.auto_close_session" value="false"/>
          <property name="hibernate.show_sql" value="true"/>
          <property name="hibernate.format_sql" value="false"/>
          <property name="hibernate.generate_statistics" value="false"/>
          <property name="hibernate.connection.autocommit" value="true"/>
          <property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
        </properties>
      </persistence-unit>
    </persistence>

在调试器模式下，当服务器尝试执行此行时 entityManager.persist(user) ;我得到这个 exception javax.persistence.TransactionRequiredException: No transactional EntityManager available .

我能做些什么来解决我的问题？