hibernate联结的子表无法update

这里能取到_evaluatescholarship，然后里面的子表也都取到了，但是更新不上去，不晓得为啥。。用的更新函数是已经写好的
public String editStuScholarship() {
String currentTime = TimeGenerator.getCurrentTime();
try {
Evaluatescholarship _evaluatescholarship = this.evaluateScholarshipService.findById(evaluatescholarship.getEno());
if (null == _evaluatescholarship) {
return "input";
}
Stubasicinfo stubasicinfo = _evaluatescholarship.getStubasicinfo();
Rewardsys rewardsys = _evaluatescholarship.getRewardsys();
Majorinfo majorinfo = _evaluatescholarship.getStubasicinfo().getMajorinfo();
stubasicinfo.setStbStuNo(evaluatescholarship.getStubasicinfo().getStbStuNo());
stubasicinfo.setStbName(evaluatescholarship.getStubasicinfo().getStbName());
stubasicinfo.setSyear(evaluatescholarship.getStubasicinfo().getSyear());
majorinfo.setMname(evaluatescholarship.getStubasicinfo().getMajorinfo().getMname());
rewardsys.setRrank(evaluatescholarship.getRewardsys().getRrank());
stubasicinfo.setMajorinfo(majorinfo);
_evaluatescholarship.setStubasicinfo(stubasicinfo);
_evaluatescholarship.setRewardsys(rewardsys);
//_evaluatescholarship.setStubasicinfo(stubasicinfo)
this.evaluateScholarshipService.update(_evaluatescholarship);
System.out.println("action getEno = "+id);
logger.info(currentTime + " 用户【" + evaluatescholarship + "】登录:");
//ActionContext.getContext().put("allList", _list);
if(stuType==1){
return "success_master";
}
else{
return "success_doctor";
}
} catch (Exception e) {
// logger.info(" ******************** Method： [execute] ******************** " + 
// "throw an exception,the reason may be username or password is wrong!");
e.printStackTrace();
return "input";
}
}
/** 
 * 向数据库更新一条对应于一个业务对象实例的记录 
 * 
 * @param entity 业务对象实例 
 */
public void update(Object entity) throws DaoException {
try {
System.out.println("update sucess");
getHibernateTemplate().update(entity);
System.out.println("111");
} catch (DataAccessException e) {
System.out.println("update failed" );
logger.error("向数据库更新 " + entity.getClass().getName() + " 的记录失败", e);
throw new DaoException("更新 " + entity.getClass().getName()
+ " 实例到数据库失败", e);
}
}