Unknown entity （Hibernate的findById方法参数必须加上包名）

曾经终败给现在 2024-02-17 20:05 16阅读 0赞

使用Hibernate的findById(java.lang.Integer id)方法

Code:

1.  public Requestnote findById(java.lang.Integer id) \{  
    
2.  try \{
3.  Requestnote instance = (Requestnote) getSession().get(
4.  "***Requestnote***", id);
5.  return instance;
6.  \} catch (RuntimeException re) \{
7.  log.error("get failed", re);
8.  throw re;
9.  \}
10. \}

报异常：

org.hibernate.MappingException: Unknown entity:Requestnote

网上百度，结果是因为findById()方法中实体类参数要带上包名。Requestnote要带上包名com.XXX.XXX写成***com.XXX.XXX.***Requestnote 就好了。

Code:

1.  public Requestnote findById(java.lang.Integer id) \{  
    
2.  try \{
3.  Requestnote instance = (Requestnote) getSession().get(
4.  "***com.XXX.XXX.***Requestnote", id);
5.  return instance;
6.  \} catch (RuntimeException re) \{
7.  log.error("get failed", re);
8.  throw re;
9.  \}
10. \}

下面是我参考的网站：

http://tieba.baidu.com/f?kz=545576481

http://hi.baidu.com/five824/blog/item/02664cd02171dfdf562c842c.html

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

通过ProductDAO 查询时出现异常  
Exception in thread "main" org.hibernate.MappingException: Unknown entity: Product  
at org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:514)  
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:66)  
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:862)  
at org.hibernate.impl.SessionImpl.get(SessionImpl.java:799)  
at com.ydq.DAO.ProductDAO.findById(ProductDAO.java:65)  
at com.ydq.test.Test.main(Test.java:10)  
  
进过测试用productDAO.findByName("pen"); 没有错误  
找了半天发现是ProductDAO里的findById 方法有问题.有问题的代码是:try \{  
Product instance = (Product) getSession()  
.get("Product", id);  
return instance;  
\} catch (RuntimeException re) \{  
log.error("get failed", re);  
throw re;  
\}  
因该改为  
try \{  
Product instance = (Product) getSession()  
.get("com.ydq.model.Product", id);  
return instance;  
\} catch (RuntimeException re) \{  
log.error("get failed", re);  
throw re;  
\}  
就是参数必须加上包名,其他方法不需要加,findById却要加,还没弄清楚为什么?