Hibernate org.hibernate.LazyInitializationException
Hibernate org.hibernate.LazyInitializationException
提问于 2011-12-08 18:59:29
我正在使用带有jsp-servlet的hibernate。当我试图访问子元素属性时，我得到了以下异常：
Servlet.service() for servlet jsp threw exception: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.ecomm.ultimatesms.messaging.persistence.pojos.Mno.startnumbers, no session or session was closed
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:380) [:3.3.2.GA]
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:372) [:3.3.2.GA]
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:365) [:3.3.2.GA]
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:108) [:3.3.2.GA]这是我的hibernate映射文件。我正在使用hibernate-mapping default-lazy="false"
<hibernate-mapping default-lazy="false">
<class name="com.ecomm.ultimatesms.messaging.persistence.pojos.Mno" table="mno" schema="public">
<id name="pkmnoid" type="long">
<column name="pkmnoid" />
<generator class="sequence">
<param name="sequence">mno_pkmnoid_seq1</param>
</generator>
</id>
<property name="name" type="string">
<column name="name" length="45" />
</property>
<set name="startnumbers" table="startnumber" inverse="false" lazy="true" fetch="select" cascade="delete">
<key>
<column name="fkmnoid" />
</key>
<one-to-many class="com.ecomm.ultimatesms.messaging.persistence.pojos.Startnumber" />
</set>
</class>
</hibernate-mapping>回答 4
Stack Overflow用户
发布于 2011-12-08 20:50:53
我不认为你需要将所有的连接设置为渴望。
或者，您需要在视图模式中使用Open Session。
你可以在这里了解更多：
http://community.jboss.org/wiki/OpenSessionInView
Stack Overflow用户
发布于 2011-12-08 19:09:10
允许您仍然打开一个打开的会话/实体管理器的一个很好的方法是，让一个过滤器在请求开始时注入EntityManager，然后在它执行后关闭它，这样您就再也不会关心它了。瞧一瞧
package com.renatogama.infra.filters;
import java.io.IOException;
import javax.persistence.EntityManager;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
@WebFilter(urlPatterns = "/*")
public class EntityManagerFilter implements Filter {
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
EntityManager em = new JPAUtil().getEntityManager();
try {
em.getTransaction().begin();
request.setAttribute("em", em);
chain.doFilter(request, response);
em.getTransaction().commit();
} catch (Exception e) {
em.getTransaction().rollback();
throw new ServletException(e);
} finally {
em.close();
}
}
@Override
public void destroy() {}
@Override
public void init(FilterConfig arg0) throws ServletException {}
}Stack Overflow用户
发布于 2011-12-08 19:04:13
由于您已经设置了lazy=true，因此必须在关闭hibernate会话之前初始化集合。这是一篇可能对你有帮助的文章，http://community.jboss.org/wiki/LazyInitializationExceptionovercome
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/8429887
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