Request processing failed; nested exception is org.apache.ibatis.binding.BindingException: Mapper method 'xxxxxxxxx' has an unsupported return type: interface java.util.List

报错信息：Request processing failed; nested exception is org.apache.ibatis.binding.BindingException: Mapper method 'xxxxxxxxx' has an unsupported return type: interface java.util.List

报错原因：返回的类型不对

报错列表

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.apache.ibatis.binding.BindingException: Mapper method 'com.shixun.dao.CakeCarDao.saveCarOrder' has an unsupported return type: interface java.util.List
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
Root Cause

org.apache.ibatis.binding.BindingException: Mapper method 'com.shixun.dao.CakeCarDao.saveCarOrder' has an unsupported return type: interface java.util.List
    org.apache.ibatis.binding.MapperMethod.rowCountResult(MapperMethod.java:94)
    org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:52)
    org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:53)
    com.sun.proxy.$Proxy15.saveCarOrder(Unknown Source)
    com.shixun.service.Impl.CakeCarServiceImpl.saveCarOrder(CakeCarServiceImpl.java:21)
    com.shixun.controller.CakeCarController.saveOder(CakeCarController.java:48)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    java.lang.reflect.Method.invoke(Method.java:498)
    org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:111)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:806)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:729)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

 解决方法：根据报错信息，查看com.shixun.dao.CakeCarDao.saveCarOrder，发现存储值时，获得了信息是List类似，但是存储是String类型。