為什么傳給前臺(tái)的itemVO獲取值全部是null

itemModel得到值了，沒有傳遞過去。

后臺(tái)報(bào)錯(cuò)，數(shù)據(jù)庫插入成功，前臺(tái)報(bào)錯(cuò)? 錯(cuò)誤信息為：添加失敗，錯(cuò)誤為? ? ? ? ?>然后就沒了

2019-02-21?09:24:28.589??INFO?8496?---?[nio-8090-exec-1]?o.a.c.c.C.[Tomcat].[localhost].[/]???????:?Initializing?Spring?FrameworkServlet?'dispatcherServlet'
2019-02-21?09:24:28.589??INFO?8496?---?[nio-8090-exec-1]?o.s.web.servlet.DispatcherServlet????????:?FrameworkServlet?'dispatcherServlet':?initialization?started
2019-02-21?09:24:28.613??INFO?8496?---?[nio-8090-exec-1]?o.s.web.servlet.DispatcherServlet????????:?FrameworkServlet?'dispatcherServlet':?initialization?completed?in?24?ms
2019-02-21?09:24:36.065??INFO?8496?---?[nio-8090-exec-1]?com.alibaba.druid.pool.DruidDataSource???:?{dataSource-1}?inited
2019-02-21?09:25:25.298??WARN?8496?---?[nio-8090-exec-1]?.m.m.a.ExceptionHandlerExceptionResolver?:?Resolved?[org.springframework.http.converter.HttpMessageConversionException:?Type?definition?error:?
[simple?type,?class?com.miaoshaproject.controller.viewobject.ItemVO];?nested?exception?is?com.fasterxml.jackson.databind.exc.InvalidDefinitionException:?No?serializer?found?for?class?
com.miaoshaproject.controller.viewobject.ItemVO?and?no?properties?discovered?to?create?BeanSerializer?(to?avoid?exception,?disable?SerializationFeature.FAIL_ON_EMPTY_BEANS)?
(through?reference?chain:?com.miaoshaproject.response.CommonReturnType["data"])]