在java中将对象列表转换为JSON数组 - Spring Boot api测试

Question

当我尝试发出 mockmvc 发布请求时，我必须在内容标签中传递对象列表，问题是每次我尝试使用 此方法 传递它：

public static String asJsonString(final Object obj) {
        try {
            final ObjectMapper mapper = new ObjectMapper();
            final String jsonContent = mapper.writeValueAsString(obj);
            return jsonContent;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

我收到此错误：

{"status":"NOT_ACCEPTABLE","errors":{"timestamp":"2021-11-29T11:53:11.2020882Z","message":"Wrong message format","details":"JSON parse error: Cannot deserialize instance of `java.util.ArrayList<Compania>` out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.util.ArrayList<Compania>` out of START_OBJECT token\n at [Source: (PushbackInputStream); line: 1, column: 1]"}}

我为仅保存 1 个对象所做的测试运行良好，但每当我尝试添加列表时它就会中断，这里有我的测试代码。

@Test
    void successSavePostCompaniaLista() throws Exception {
        Compania c1 = new Compania("Compania1 list",
            "name1",
            "---",
            "---",
            null,
            null);
        Compania c2 = new Compania("Compania2 list",
            "name2",
            "---",
            "---",
            null,
            null);

        List<Compania> companias = List.of(c1,c2);
        when(companiaRepository.save(any(Compania.class))).then(returnsFirstArg());

        this.mockMvc.perform(
                post("/companias/lista")
                    .header("authorization", "Bearer " + token)
                    .content(asJsonString(companias)) //<-- Here gives me errors
                    .contentType(MediaType.APPLICATION_JSON))
            .andDo(print())
            .andExpect(status().isCreated())
            .andExpect(jsonPath("$.result[0].success[0]").isNotEmpty())
            .andExpect(jsonPath("$.result[0].success[0].name").value(c1.getName()))
            .andExpect(jsonPath("$.result[0].success[1].name").value(c2.getName()));

    }

工作原理与此类似，但只使用一个对象。

http的方向，其余的都ok。

谢谢！

编辑。这是我正在尝试测试的服务

public Map<String, Object> postListCompanias(List<Compania> companias) {
        for (int i = 0; i < companias.size(); i++) {
            Compania companiaN = companias.get(i);
            companiaN.setId(null);

            companiaRepository.save(companias.get(i));
            System.out.println(companias.get(i));
        }

        Map<String, Object> mappedResult = Collections.singletonMap(
            "result",
            List.of(
                Collections.singletonMap(
                    "success",
                    companias
                )
            )
        );
        return mappedResult;
    }

这里是控制器：

@ResponseStatus(HttpStatus.CREATED)
    @PostMapping("/lista")
    public Map<String, Object> createCompanias(@RequestBody List<Compania> companias) {

        return companiaService.postListCompanias(companias);
    }

Answer 1

在我看来，问题在于您试图将类似以下 JSON 的内容传递给content：

[
  {
    "compania1_list": "Compania1 list",
    "name1": "name1",
    "s": "---",
    "s1": "---",
    "o": null,
    "o1": null
  },
  {
    "compania1_list": "Compania2 list",
    "name1": "name2",
    "s": "---",
    "s1": "---",
    "o": null,
    "o1": null
  }
]

这是一个带有 2 个 JSON 对象的 JSON 数组，而不是一个带有 2 个 JSON 对象的 JSON 数组的 JSON 对象。我的猜测是 MockHttpServletRequestBuilder.content() 方法不期望这样的 JSON。

话虽如此，我会将您的控制器更改为接受对象而不是集合，如下所示：

@ResponseStatus(HttpStatus.CREATED)
@PostMapping("/lista")
public Map<String, Object> createCompanias(@RequestBody CompaniasCreationRequest companiasCreationRequest) {
    return companiaService.postListCompanias(companiasCreationRequest.getCompanias());
}

如下CompaniasCreationRequest：

public class CompaniasCreationRequest {
    private List<Compania> companias;

    public CompaniasCreationRequest(List<Compania> companias) {
        this.companias = companias;
    }

    public List<Compania> getCompanias() {
        return companias;
    }

    public void setCompanias(List<Compania> companias) {
        this.companias = companias;
    }
}

在您的测试中，这将意味着以下更改：

@Test
void successSavePostCompaniaLista() throws Exception {
    Compania c1 = new Compania("Compania1 list",
        "name1",
        "---",
        "---",
        null,
        null);
    Compania c2 = new Compania("Compania2 list",
        "name2",
        "---",
        "---",
        null,
        null);

    CompaniasCreationRequest companiasCreationRequest = new CompaniasCreationRequest(List.of(c1,c2));
    
    when(companiaRepository.save(any(Compania.class))).then(returnsFirstArg());

    this.mockMvc.perform(
            post("/companias/lista")
                .header("authorization", "Bearer " + token)
                .content(asJsonString(companiasCreationRequest))
                .contentType(MediaType.APPLICATION_JSON))
        .andDo(print())
        .andExpect(status().isCreated())
        .andExpect(jsonPath("$.result[0].success[0]").isNotEmpty())
        .andExpect(jsonPath("$.result[0].success[0].name").value(c1.getName()))
        .andExpect(jsonPath("$.result[0].success[1].name").value(c2.getName()));
}

现在您的请求正文将如下所示（这是一种更标准的 JSON 格式）：

{
  "companias": [
    {
      "compania1_list": "Compania1 list",
      "name1": "name1",
      "s": "---",
      "s1": "---",
      "o": null,
      "o1": null
    },
    {
      "compania1_list": "Compania2 list",
      "name1": "name2",
      "s": "---",
      "s1": "---",
      "o": null,
      "o1": null
    }
  ]
}