ssm项目,使用parameterType的包装类时，报错org.springframework.beans.InvalidPropertyException

User类【有Headphoto类】

Headphoto类

UserDao.java

UserDao.xml

报错：
严重: Servlet.service() for servlet [springmvc] in context with path [/WeiQ] threw exception [Request processing failed; nested exception is org.springframework.beans.InvalidPropertyException: Invalid property ‘headPhoto[flag]’ of bean class [com.wyj.beans.User]: Property referenced in indexed property path ‘headPhoto[flag]’ is neither an array nor a List nor a Map; returned value was [HeadPhoto [id=null, path=null, flag=null]]] with root cause

org.springframework.beans.InvalidPropertyException: Invalid property ‘headPhoto[flag]’ of bean class [com.wyj.beans.User]: Property referenced in indexed property path ‘headPhoto[flag]’ is neither an array nor a List nor a Map; returned value was [HeadPhoto [id=null, path=null, flag=null]]

前端的数据都能传过来，但是一传到dao就报错，好像说是我这个headphoto类找不到，但是在前端传过来时我已经打印出来了，有数据的，求大神指点，一天没有解决