java - JUnit POST @Test 返回空字符串

Question

问题

我正在尝试为 Spring Controller 编写一个测试，但测试本身似乎没有返回任何内容。奇怪的是，如果我用 Postman 手动测试它，我会得到预期的结果。

期待

我的期望

{
  "title": "My Third Todo"
}

postman

我得到了什么(空响应？)

相关代码

TodoService

@Service
public class TodoService {

    private TodoRepository todoRepository;

    @Autowired
    public TodoService(TodoRepository todoRepository) {
        this.todoRepository = todoRepository;
    }

    public List<Todo> findAll() {
        return todoRepository.findAll();
    }

    public Todo findById(Long todoId) {
        return todoRepository.findById(todoId).orElse(null);
    }

    public Todo save(Todo todo) {
        return todoRepository.save(todo);
    }

    public void deleteById(Long todoId) {
        todoRepository.deleteById(todoId);
    }

}

TodoController

@RestController
@RequestMapping("/api/todos")
public class TodoController {

    private TodoService todoService;

    @Autowired
    public TodoController(TodoService todoService) {
        this.todoService = todoService;
    }

    @PostMapping
    public Todo save(@RequestBody Todo todo) {
        return todoService.save(todo);
    }

}

TodoControllerTest

@RunWith(SpringRunner.class)
@WebMvcTest(TodoController.class)
public class TodoControllerTest {

    @Autowired
    private MockMvc mockMvc;

    @MockBean
    private TodoService todoService;

    private List<Todo> todos;

    public TodoControllerTest() {
        Todo firstTodo = new Todo();
        firstTodo.setId(1L);
        firstTodo.setTitle("My First Todo");

        Todo secondTodo = new Todo();
        secondTodo.setId(2L);
        secondTodo.setTitle("My Second Todo");

        todos = new ArrayList<>();
        todos.add(firstTodo);
        todos.add(secondTodo);
    }

    @Test
    public void save() throws Exception {
        Todo thirdTodo = new Todo();
        thirdTodo.setId(3L);
        thirdTodo.setTitle("My Third Todo");

        when(todoService.save(thirdTodo)).thenReturn(thirdTodo);

        String mock = mockMvc.perform(post("/api/todos")
                .contentType(MediaType.APPLICATION_JSON)
                .content("{\"title\": \"My Third Todo\"}"))

                .andExpect(status().isOk())

                .andReturn()
                .getResponse()
                .getContentAsString();

        System.out.println("\n\n\n");
        System.out.println("Mock: " + mock);
        System.out.println("\n\n\n");
    }

}

Answer 1

看来，在 POST 请求中发送 JSON 时，您需要对 JSON 表示的对象进行 1:1 映射。在上面的 @Test 示例中，我没有这样做。

示例类

public class MyObject {
    private Long id;
    private String title;

    // Constructor, getters, and setters
}

对于示例类 my MyObject，当您想将其传递给 RequestBuilder.post(...).content(...) 时，您显然需要像这样 1:1 映射

RequestBuilder.post(...)
  content("{\"id\":1,\"title\":\"My Third Todo\"}\")

另一个建议是使用 ObjectMapper 将对象转换为 JSON。

Todo todo = new Todo(1L, "My Third Todo");
ObjectMapper mapper = new ObjectMapper();

String todoJson = mapper.writeValueAsString(todo);

mockMvc.perform(RequestBuilder.post("/api/todos")
                .contentType(MediaType.APPLICATION_JSON)
                .content(todoJson))
    // do whatever else you need