Optional int parameter ‘xxx‘ is present but cannot be translated into a null value due to being

异常

java.lang.IllegalStateException: Optional int parameter 'start' is present but cannot be translated into a null value due to being declared as a primitive type. Consider declaring it as object wrapper for the corresponding primitive type.
	org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.handleNullValue(AbstractNamedValueMethodArgumentResolver.java:245)
	org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:116)
	org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
	org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)
	org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
	org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879)
	org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793)
	org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:626)
	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
	org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
	org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)

原因

解决

将int改成Integer即可。

但这只是表面的原因，在本例中导致这个错误的原因是请求该地址还需要携带两个参数，但并没有

所以导致了这个错误，因为没有对两个参数进行非null判断。

但是int类型属于基本类型，无法进行非null判断，但Integer属于包装类型，可以进行非null判断。

所以需要在请求地址上加上参数，并同时对参数进行非null判断。