Mockito.when（）。thenReturn（）没有反映在@Component函数中

Question

当我使用我的测试类中运行以下代码时：

Mockito.when(accountHelper.convertAccountToJson(account)).thenReturn(jsonObject);

它返回jsonObject。但是，在我的AccountController中，以下代码返回null：

JSONObject accountJson = accountHelper.convertAccountToJson(account);

有人可以解释为什么模拟回应没有被反映出来吗？提前致谢。

这是我的代码： 识别TestClass

 @RunWith(MockitoJUnitRunner.class)
    public class AccountControllerTest {

        @InjectMocks private AccountController accountController;
        @Mock private AccountHelper accountHelper;

        MockMvc mockMvc;

        @Before
        public void setup() throws Exception {
            MockitoAnnotations.initMocks(this);
            mockMvc = MockMvcBuilders.standaloneSetup(accountController).build();
        }

        @Test
        public void createAccountEmptyMessage() throws Exception{
            String jsonString = "{}";
            String expectedReturnBody = "{\"name\":"test"}";

            Account account = new Account(test);
            JSONObject jsonObject = new JSONObject("{\"name\":"test"}");

            Mockito.when(accountHelper.convertAccountToJson(account)).thenReturn(jsonObject);

            mockMvc.perform(post("/createAccount").contentType(MediaType.APPLICATION_JSON).characterEncoding("UTF-8")
                    .accept(MediaType.APPLICATION_JSON).content(jsonString))
                    .andExpect(content().string(expectedReturnBody));
        }
    }

助手类

@Component
public class AccountHelper {
    public JSONObject convertAccountToJson(Account account) {
    String jsonString;
    JSONObject json;

    Gson gson = new Gson();

    try{
        jsonString = gson.toJson(account);
        json = new JSONObject(jsonString);
        logger.info(jsonString);
    } catch (Exception e) {
        return null;
    }

    return json;
}

控制器

@RestController
public class AccountController {
    @Autowired private AccountService accountService;
    @Autowired private AccountHelper accountHelper;

    @RequestMapping(method = RequestMethod.POST, value = "/createAccount")
    public ResponseEntity<Object> createAccount(@RequestBody(required= false) Account account) {
        try {
            JSONObject accountJson = accountHelper.convertAccountToJson(account); //Return null

            //Create Account

            return new ResponseEntity(accountJson.toString(), HttpStatus.OK);

        } catch (Exception e) {
            return new ResponseEntity(e.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }
}