如何避免在測試用過的MockMvc中出現NullPointerException？

Question

我有控制器：

@Controller
public class EventMenuController{

    @RequestMapping(value = "/updateEvent", method = RequestMethod.POST)
    public String updateEvent(Model model,
            @Valid @ModelAttribute("existedEvent") Event event,
            BindingResult result,
            @ModelAttribute("linkedCandidates") Set<Candidate> candidates,
            @ModelAttribute("linkedvacancies") Set<Vacancy> vacancies,
            @RequestParam(required = true, value = "selectedEventStatusId")Integer EventStatusId,
            @RequestParam(required = true, value = "selectedEventTypeId")Integer EventTypeId ,
            RedirectAttributes attributes) {
        if (result.hasErrors()) {
            //model.addAttribute("idEvent", event.getId());
            event.setCandidates(candidates);
            event.setVacancies(vacancies);
            return "eventDetails";
        }
        eventService.updateEventAndLinkedEntities(event, candidates, vacancies ,EventTypeId,EventStatusId);
        attributes.addAttribute("idEvent",event.getId() );//event is null therefore NPE here
        attributes.addAttribute("message", "submitted correctly at "+new Date());
        return "redirect:eventDetails";
     }
 }

為了測試此方法，我編寫了以下課程：

@ContextConfiguration(locations = { "classpath:/test/BeanConfigUI.xml" })
@RunWith(SpringJUnit4ClassRunner.class)
@WebAppConfiguration
public class EventMenuControllerTest {


    @Test
    public void updateEvent() throws Exception{
        MockHttpServletRequestBuilder request = MockMvcRequestBuilders
                .post("/updateEvent");
        request.param("selectedEventStatusId", "1");
        request.param("selectedEventTypeId", "1");

        EventMenuController eventMenuController = (EventMenuController) wac.getBean("eventMenuController");
        EventService mockEventService = Mockito.mock(EventService.class);
        eventMenuController.eventService = mockEventService;

        Mockito.doNothing().when(mockEventService).updateEventAndLinkedEntities(any(Event.class), any(Set.class),any(Set.class), any(Integer.class), any(Integer.class));

        ResultActions result = mockMvc.perform(request);

        result.andExpect(MockMvcResultMatchers.view().name("redirect:eventDetails"));
        result.andExpect(MockMvcResultMatchers.model().attributeExists("idEvent"));
        result.andExpect(MockMvcResultMatchers.model().attributeExists("message"));

    }

}

在服務器端執行的流程請求中，我看到錯誤，向我顯示事件對象為null。

題：

我必須使用MockMvc將通過事件寫入服務器端（控制器方法）的什么請求？

Answer 1

Event類對象未初始化。 您可以創建一個Event對象或創建的模擬Event取決於你的測試用例對象，並將其發送給EventMenuController類對象。 您可以執行類似於將EventService的模擬對象發送到EventMenuController 。

更好的做法是將字段用作類的一部分，而不是方法的一部分。 這將使您可以靈活地模擬任何字段。