hibernate懒加载could not initialize proxy - no Session

原创已于 2022-04-11 17:35:26 修改 · 1.5k 阅读

9 ·

CC 4.0 BY-SA版权

文章标签：

#hibernate #spring

于 2022-04-11 17:12:49 首次发布

spring 专栏收录该内容

1 篇文章

订阅专栏

本文介绍了如何在单元测试中遇到的Spring JPA懒加载问题，即在使用OpenEntityManagerInViewFilter后，如何通过Spring上下文获取Session并确保事务管理来避免'couldnotinitializeproxy-noSession'异常。作者提供了具体代码示例，并分享了排错和解决方案。

问题描述：

两个model：salesOrder SalesOrderItem 为oneToMany fetch = FetchType.LAZY

单元测试从数据库获取salesOrder后，获取其子集合List<SalesOrderItem> salesOrderItems

报如下异常

分析原因之后发现过滤器中引入了OpenEntityManagerInViewFilter来将一个JPAsession与一次完整的请求过程对应的线程相绑定，但是该过滤器只对controller层的请求起作用，对于mq或者定时任务的对象获取就会报could not initialize proxy - no Session，OpenEntityManagerInViewFilter将JPAsession统一交由spring管理，所以从spring上下文中获取session，操作完之后再关闭，就可解决问题代码如下：

package com.wintelia.orderserver.api.controller.order;

import com.foreveross.callcenter.domain.sale.SalesOrder;
import com.foreveross.callcenter.domain.sale.SalesOrderItem;
import com.wintelia.orderserver.api.OderServerApiApplication;
import com.wintelia.orderserver.application.service.order.SalesOrderService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.ApplicationContext;
import org.springframework.orm.jpa.EntityManagerFactoryUtils;
import org.springframework.orm.jpa.EntityManagerHolder;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.transaction.support.TransactionSynchronizationManager;

import javax.annotation.Resource;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = OderServerApiApplication.class)
public class OrderDetailLazyTest {
    @Autowired
    private SalesOrderService orderService;
    private static final Logger log = LoggerFactory.getLogger(OrderDetailLazyTest.class);
    @Resource
    private ApplicationContext ctx;
    @Test
    public void queryOrderBySysOrderNo() {

        EntityManagerFactory entityManagerFactory = ctx.getBean(EntityManagerFactory.class);
        EntityManager entityManager = entityManagerFactory.createEntityManager();
        EntityManagerHolder entityManagerHolder = new EntityManagerHolder(entityManager);
        TransactionSynchronizationManager.bindResource(entityManagerFactory, entityManagerHolder);

        SalesOrder salesOrder = orderService.findByOrderNo2("*******");

        for(SalesOrderItem item : salesOrder.getSalesOrderItems()){
            log.info("票号信息为{}",item.getTicketNo());

        }
        TransactionSynchronizationManager.unbindResource(entityManagerFactory);
        EntityManagerFactoryUtils.closeEntityManager(entityManager);
    }
}

参考文章spring 中的懒加载与事务 -- 排坑记录 | 徐靖峰|个人博客