java.lang.IllegalStateException:EntityManager已使用HSQL关闭

出于教育目的，我正在构建一个简单的SpringWeb应用程序，但持久性级别有一个小问题—java.lang.IllegalStateException:EntityManager is closed，当我试图从数据库中获取某些内容时抛出。对象是持久化的，但当我尝试进行查询时，会抛出异常。因此，我将Hibernate与HSQL inmemory db一起使用，下面是我的persistence.xml：

<?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_2_0.xsd"
         version="2.0">

<persistence-unit name="pp_persistence_unit" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>

    <properties>
        <property name="javax.persistence.jdbc.driver" value="org.hsqldb.jdbcDriver"/>
        <property name="javax.persistence.jdbc.url" value="jdbc:hsqldb:mem:testDB"/>
        <property name="sqltool.charset" value="UTF-8" />
        <property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect"/>
        <property name="show_sql" value="true"/>
        <property name="hibernate.hbm2ddl.auto" value="create"/>
        <property name="current_session_context_class" value="thread"/>
        <property name="hibernate.show_sql" value="true" />
    </properties>
</persistence-unit>

这里是getConnectionsCount方法

public int getConnectionsCount() {
    Query query = entityManager.createQuery("select count(c.id) from Connection c");
    return (Integer)query.getSingleResult();
}

我真的不知道是什么问题。我假设它可能来自数据库的编码，但我尝试将其设置为UTF-8，但错误仍然是一样的

很抱歉忘记了，这是我的application-context.xml：

<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:context="http://www.springframework.org/schema/context"
 xmlns:tx="http://www.springframework.org/schema/tx"
 xmlns:mvc="http://www.springframework.org/schema/mvc"
 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-3.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/tx 
http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">

<context:component-scan base-package="web.task.business">
    <context:include-filter type="annotation" expression="org.springframework.stereotype.Service" />
</context:component-scan>

<context:component-scan base-package="web.task.dao">
    <context:include-filter type="annotation" expression="org.springframework.stereotype.Repository" />
</context:component-scan>

<context:component-scan base-package="web.task.transformation">
    <context:include-filter type="annotation" expression="web.task.annotations.Transformation" />
</context:component-scan>

<bean id="ppEntityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
    <property name="persistenceUnitName" value="pp_persistence_unit" />
</bean>

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

<tx:annotation-driven transaction-manager="transactionManager"/>

<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />

---

请共享您的spring上下文xml抱歉，我真的忘记了-帖子已上载。您可以发布web.xml吗？您还可以发布您的web.task.dao.ConnectionDao.getconnectionscout方法吗？我发布它没有问题，但每当我尝试从数据库获取内容时，都会引发该异常

<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:context="http://www.springframework.org/schema/context"
 xmlns:tx="http://www.springframework.org/schema/tx"
 xmlns:mvc="http://www.springframework.org/schema/mvc"
 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-3.2.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.2.xsd
http://www.springframework.org/schema/tx 
http://www.springframework.org/schema/tx/spring-tx-3.2.xsd ">

<context:component-scan base-package="web.task.business">
    <context:include-filter type="annotation" expression="org.springframework.stereotype.Service" />
</context:component-scan>

<context:component-scan base-package="web.task.dao">
    <context:include-filter type="annotation" expression="org.springframework.stereotype.Repository" />
</context:component-scan>

<context:component-scan base-package="web.task.transformation">
    <context:include-filter type="annotation" expression="web.task.annotations.Transformation" />
</context:component-scan>

<bean id="ppEntityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
    <property name="persistenceUnitName" value="pp_persistence_unit" />
</bean>

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

<tx:annotation-driven transaction-manager="transactionManager"/>

<bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor" />