求解：SessionFactory.getCurrentSession()的異常問題

做了一個Spring4和hibernate4的一個集成的例子，通過一個BasicHibernateDaoImpl.java構建基本的DAO處理類，代碼片段如下：

package org.craig.dao.impl.base;

import java.io.Serializable;
import java.util.List;
import org.craig.dao.iface.base.IBasicDao;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;

public abstract class BasicHibernateDaoImpl<T> implements IBasicDao<T> {
    // DAO組件進行持久化操作底層依賴的SessionFactory組件
    private SessionFactory sessionFactory;
    
    // 根據ID加載實體
    @Override
    @SuppressWarnings("unchecked")
    public T get(Class<T> entityClazz, Serializable id) {
        Session session = getSessionFactory().getCurrentSession();
        return (T) session.get(entityClazz, id);
    }

    // 保存實體
    @Override
    public Serializable save(T entity) {
        return getSessionFactory().getCurrentSession().save(entity);
    }

    // 更新實體
    @Override
    public void update(T entity) {
        getSessionFactory().getCurrentSession().saveOrUpdate(entity);
    }

    // 刪除實體
    @Override
    public void delete(T entity) {
        getSessionFactory().getCurrentSession().delete(entity);
    }

    // 根據ID刪除實體
    @Override
    public void delete(Class<T> entityClazz, Serializable id) {
        getSessionFactory()
                .getCurrentSession()
                .createQuery(
                        "delete " + entityClazz.getSimpleName()
                                + " en where en.id = ?0").setParameter("0", id)
                .executeUpdate();
    }

    // 獲取所有實體
    @Override
    public List<T> findAll(Class<T> entityClazz) {
        return find("select en from " + entityClazz.getSimpleName() + " en");
    }

 

在spring的配置中如下：

<bean id="abstractBasicDao" class="org.craig.dao.impl.base.BasicHibernateDaoImpl" abstract="true"
        p:sessionFactory-ref="sessionFactory"/>    

接着是員工DAO：

package org.craig.dao.impl;

import org.craig.dao.iface.IEmployeeDao;
import org.craig.dao.impl.base.BasicHibernateDaoImpl;
import org.craig.pojo.Employee;

public class EmployeeDaoImpl extends BasicHibernateDaoImpl<Employee> implements
        IEmployeeDao {
    
}

在spring中的配置如下：

    <bean id="employeeDao" parent="abstractBasicDao" class="org.craig.dao.impl.EmployeeDaoImpl"/> 

 

接下來是spring和heibernate集成的配置

 <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
        destroy-method="close"
        p:driverClass="com.mysql.jdbc.Driver"
        p:jdbcUrl="jdbc:mysql://localhost:3306/info"
        p:user="root"
        p:password="123456"
        p:maxPoolSize="40"
        p:minPoolSize="2"
        p:initialPoolSize="2"
        p:maxIdleTime="30" />
    <!-- 定義Hibernate的SessionFactory，SessionFactory需要依賴數據源，注入dataSource -->
    <bean id="sessionFactory" 
        class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"
        p:dataSource-ref="dataSource">
        <property name="annotatedClasses">
           <list>
                <value>org.craig.pojo.Employee</value>
            </list>
          </property>
        <!-- 定義Hibernate SessionFactory的屬性 -->
        <property name="hibernateProperties">
            <props>
                <!-- 指定Hibernate的連接方言 -->
                <prop key="hibernate.dialect">
                    org.hibernate.dialect.MySQL5Dialect</prop>
                <prop key="hibernate.show_sql">true</prop>
                <prop key="hibernate.format_sql">true</prop>
                  <prop key="hibernate.current_session_context_class">jta</prop>
         
                <prop key="hibernate.connection.autocomit">false</prop>
            
            </props>
        </property>
    </bean>
    
    <!-- 增加事物 -->
    <bean id="transactionManager" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"
        p:sessionFactory-ref="sessionFactory"/>
    
    <!-- AOP -->
    <tx:advice id="txEmployee" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="*" propagation="REQUIRED" />
        </tx:attributes>
    </tx:advice>

    <aop:config>
        <aop:advisor advice-ref="txEmployee" pointcut="execution(* org.craig.dao.impl.*.*(..))"/>
    </aop:config>

在登錄的servlet代碼中有如下操作：

IEmployeeDao employeeDao = SpringUtil.getBean("employeeDao", IEmployeeDao.class);
            Employee emp = employeeDao.get(Employee.class, name);

這里的employeeDao.get()方法會調用BasicHibernateDaoImpl.java中的get()，在Session session = getSessionFactory().getCurrentSession();這里會報錯誤。錯誤代碼如下：

嚴重: Servlet.service() for servlet login threw exception
org.hibernate.HibernateException: Unable to locate current JTA transaction
    at org.hibernate.context.internal.JTASessionContext.currentSession(JTASessionContext.java:92)
    at org.hibernate.internal.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:1014)
    at org.craig.dao.impl.base.BasicHibernateDaoImpl.get(BasicHibernateDaoImpl.java:18)
    at org.craig.manager.LoginServlet.doGet(LoginServlet.java:36)
    at org.craig.manager.LoginServlet.doPost(LoginServlet.java:49)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:263)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:584)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:662)

但是如果用SessionFactory.openSession()替換掉getCurrentSession()是可以獲取到員工信息的。首先看了官方的說明，getCurrentSession()的前提是系統中擁有全局JTA事物，於是在tomcat中加入jotm的JTA事物管理，並且在啟動時，控制台顯示了JOTM TransactionManager的消息，並且在JSP頁面也能通過代碼獲得UerTransaction，此時的transactionmanager的配置如下：

<bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">  
        <property name="transactionSynchronizationRegistryName" value="java:comp/env/jta/jotmTransaction"></property>  
        <property name="transactionManagerName" value="java:comp/UserTransaction" />  
    </bean> 

但是依然報錯，錯誤信息跟上面的一樣。求高人指點！感謝了。