MockMvc POST测试中MultipartFile为何为null？

问题描述 #

Spring Boot项目里用MockMvc发起POST请求，setup步骤已经正确初始化了MockMultipartFile，但控制器接收的MultipartFile始终是null。

控制器代码 #

@PostMapping(path = MANUAL_TRIGGER)
private @ResponseBody ResponseEntity<String> bpsDataLoad(
    @RequestParam(required = false) MultipartFile positionFile) throws IOException {

测试代码 #

@RunWith(SpringRunner.class)
@SpringBootTest
@ActiveProfiles(profiles = {"test"})
@AutoConfigureMockMvc(addFilters = false)
class BPSDataLoadControllerTest {

  @Autowired private JdbcTemplate jdbcTemplate;
  @Autowired MockMvc mockMvc;

  @Value("${spring.jpa.properties.hibernate.default_schema}")
  String defaultSchema;

  MockMultipartFile file;
  MockMultipartFile invalidFile;
  Path path = Paths.get("src/test/resources/testdata/oneposition.txt");
  Path invalidPath =
      Paths.get("src/test/resources/testdata/invalidposition.txt");
  String name = "file.txt";
  String originalFileName = "file.txt";
  String contentType = "text/plain";
  byte[] content = null;
  byte[] invalidContent = null;

  @BeforeEach
  public void setup() {
    try {
      content = Files.readAllBytes(path);
      invalidContent = Files.readAllBytes(invalidPath);
    } catch (final IOException e) {
    }
    file = new MockMultipartFile(name, originalFileName, contentType, content);
    invalidFile = new MockMultipartFile(name, originalFileName, contentType, invalidContent);

    JdbcTestUtils.deleteFromTables(jdbcTemplate, defaultSchema + ".bps_position_table");
  }

  @Test
  @Disabled("File is coming in as null, works on smoke test.")
  public void bpsDataLoadTestOK() throws Exception {
    mockMvc
        .perform(MockMvcRequestBuilders.multipart("/perform-bpsLoad").file(file))
        .andExpect(status().isOk())
        .andExpect(content().contentType("text/plain;charset=UTF-8"));
  }
}

已尝试操作 #

试过用@WebApplicationContext初始化MockMvc，问题依旧，控制器接收的文件还是null，断言失败。尝试代码：

MockMvc mockMvc 
  = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
mockMvc.perform(multipart("/perform-bpsLoad").file(file))
  .andExpect(status().isOk());

修复方案 #

1. 匹配参数名称：控制器@RequestParam的参数名是positionFile，但测试里创建MockMultipartFile时第一个参数用的是file.txt，两者不匹配导致映射失败。修改测试代码中MockMultipartFile的第一个参数为positionFile：

   file = new MockMultipartFile("positionFile", originalFileName, contentType, content);
   invalidFile = new MockMultipartFile("positionFile", originalFileName, contentType, invalidContent);
   

2. 修正控制器方法权限：当前控制器方法是private，Spring无法正确处理请求，改成public：

   @PostMapping(path = MANUAL_TRIGGER)
   public @ResponseBody ResponseEntity<String> bpsDataLoad(
       @RequestParam(required = false) MultipartFile positionFile) throws IOException {
   

3. 校验请求路径：确认测试中使用的/perform-bpsLoad和控制器MANUAL_TRIGGER常量定义的路径完全一致，避免拼写错误。

内容的提问来源于stack exchange，提问作者Beez