最近学习SSH出现这个情况，也比较奇怪，我用junit测试的没问题，但提交的表单数据就有问题出现org.hibernate.MappingException: Unknown entity:异常：
异常信息：

stujiating1 : com.xjgl.server.entity.Stujiatinginfotb@5868d40c
Hibernate: select stujiating0_.id as id1_, stujiating0_.sno as sno1_, stujiating0_.jiatingjiegou as jiatingj3_1_, stujiating0_.jiatingfenwei as jiatingf4_1_, stujiating0_.jiatingdizhi as jiatingd5_1_, stujiating0_.jiatingdianhua as jiatingd6_1_, stujiating0_.youbian as youbian1_, stujiating0_.dushengzhinv as dushengz8_1_ from stujiatinginfo stujiating0_ where stujiating0_.sno=?
2014/11/10 12:48:05[DEBUG][com.xjgl.server.dao.StujiatinginfoDao]:144 -- 添加学生101_1的家庭信息成功
		==================================================
		student.getStujiatinginfo() : com.xjgl.server.entity.Stujiatinginfotb@1fd7855
		stujiating2.sno : 101_2
		stujiating2.youbian : 
Hibernate: insert into student (name, sno, id) values (?, ?, ?)
Hibernate: insert into stujiatinginfo (sno, jiatingjiegou, jiatingfenwei, jiatingdizhi, jiatingdianhua, youbian, dushengzhinv, id) values (?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: select stujiating0_.id as id1_, stujiating0_.sno as sno1_, stujiating0_.jiatingjiegou as jiatingj3_1_, stujiating0_.jiatingfenwei as jiatingf4_1_, stujiating0_.jiatingdizhi as jiatingd5_1_, stujiating0_.jiatingdianhua as jiatingd6_1_, stujiating0_.youbian as youbian1_, stujiating0_.dushengzhinv as dushengz8_1_ from stujiatinginfo stujiating0_ where stujiating0_.sno=?
2014/11/10 12:48:05[ERROR][org.apache.struts2.dispatcher.Dispatcher]:38 -- Exception occurred during processing request: Unknown entity: com.xjgl.server.entity.Stujiatinginfotb$$EnhancerByCGLIB$$5d40c870
org.hibernate.MappingException: Unknown entity: com.xjgl.server.entity.Stujiatinginfotb$$EnhancerByCGLIB$$5d40c870
	at org.hibernate.impl.SessionFactoryImpl.getEntityPersister(SessionFactoryImpl.java:691)
	at org.hibernate.impl.SessionImpl.getEntityPersister(SessionImpl.java:1485)
	at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:120)
	at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
	at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:56)
	at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
	at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:50)
	at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
	at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:713)
	at org.hibernate.impl.SessionImpl.save(SessionImpl.java:701)
	at org.hibernate.impl.SessionImpl.save(SessionImpl.java:697)
	at com.xjgl.server.dao.StujiatinginfoDao.saveStujiatinginfo(StujiatinginfoDao.java:143)

程序代码：
其中：stujiating1 能保存成功，stujiating2不能保存成功，异常信息就是在保存stujiating2时出现的

Stujiatinginfotb stujiating1 = new Stujiatinginfotb();
		stujiating1.setId(sid + "_1");
		stujiating1.setSno(sno + "_1");
		System.out.println("		stujiating1 : " + stujiating1);
		stujiatinginfoDao.saveStujiatinginfo(stujiating1);

		System.out.println("		==================================================");
		Stujiatinginfotb stujiating2 = new Stujiatinginfotb();
		System.out.println("		student.getStujiatinginfo() : " + student.getStujiatinginfo());
		stujiating2 = student.getStujiatinginfo();
		stujiating2.setId(sid + "_2");
		stujiating2.setSno(sno + "_2");
		System.out.println("		stujiating2.sno : " + stujiating2.getSno());
		System.out.println("		stujiating2.youbian : " + stujiating2.getYoubian());
		stujiatinginfoDao.saveStujiatinginfo(stujiating2);
		log.debug("保存学生家庭信息成功");

测试代码：

@Test
	public void testPutStudent() throws MyException {
		StudentAll student = new StudentAll();
		Stujiatinginfotb stujiatinginfo = new Stujiatinginfotb();
		student.setStujiatinginfo(stujiatinginfo);

		student.setName("zhangsan");
		student.setSno("901");

		boolean b = teacherService.putStudent(student);

		System.out.println("return : " + b);
	}