当我想通过hibernate连接到我的数据库时,我得到了这个异常,我正在尝试很多我在互联网上找到的东西,但没有任何帮助,我的一些文件：
带连接的dao类：
@Repository
public class UserDaoImpl implements UserDao {
@Autowired
SessionFactory sessionFactory;
//the problem with query is here
public List<User> getAllUsers() {
return sessionFactory.getCurrentSession().createSQLQuery("SELECT * FROM user").list();
}
}
web.xml中：
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name>Archetype Created Web Application</display-name>
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>*.htm</url-pattern>
</servlet-mapping>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:context.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
</web-app>
我的servlet：
<?xml version="1.0" encoding="UTF-8"?>
<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"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">
<context:annotation-config />
<context:component-scan base-package="com.lime" />
<mvc:annotation-driven />
<mvc:default-servlet-handler />
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/" />
<property name="suffix" value=".jsp" />
</bean>
</beans>
和context.xml：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
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.xsd">
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.PostgreSQL9Dialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.current_session_context_class">thread</prop>
<prop key="hibernate.connection.driver_class">org.postgresql.Driver</prop>
<prop key="hibernate.connection.url">jdbc:postgresql://localhost:5432/come_to_blog_db</prop>
<prop key="hibernate.connection.username">postgres</prop>
<prop key="hibernate.connection.password">admin</prop>
</props>
</property>
<property name="annotatedClasses">
<list>
<value>com.lime.model.User</value>
</list>
</property>
</bean>
</beans>
解决方法:
试试看吧
@Repository
public class UserDaoImpl implements UserDao {
@Autowired
SessionFactory sessionFactory;
//the problem with query is here
public List<User> getAllUsers() {
Session session=null;
try
{
Session session = sessionFactory.openSession();
return session.createSQLQuery("SELECT * FROM user").list();
}
catch(Exception e)
{
//Logging
}
finally
{
if(session !=null && session.isOpen)
{
session.close();
session=null;
}
}
}
}
更新
使用genericDAO,它获取当前会话,需要使用openSession()显式打开,而getCurrentSession()只是将它附加到当前会话.据作者说
GenericDAO makes the assumption that you will be handling transactions
externally to the DAO
标签：java,spring,hibernate 来源： https://codeday.me/bug/20191008/1872132.html
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