使用Apache HttpClient向Spring Boot上传Multipart文件遇415错误

问题详情 #

Spring Boot应用的文件上传端点代码如下：

@PostMapping("/")
public ResponseEntity<FileUploadResponseDto> upload(@RequestPart("details") FileUploadDto fileUploadDto,@RequestParam("file") MultipartFile file){
  try {
      return ResponseEntity.ok( fileUploadService.uploadFile(fileUploadDto,file));
  }catch (Exception e){
      return ResponseEntity.status(406).body(new FileUploadResponseDto(false,e.getMessage()));
  }
};

使用Postman测试该接口一切正常，但通过Apache HttpClient调用时，Spring Boot返回application/octet-stream is not supported错误，响应信息如下：

HttpResponseProxy{HTTP/1.1 415 [Accept: application/json, application/*+json, Content-Type: application/json, Transfer-Encoding: chunked, Date: Sun, 11 Feb 2024 22:02:27 GMT, Keep-Alive: timeout=60, Connection: keep-alive] ResponseEntityProxy{[Content-Type: application/json,Chunked: true]}}

对应的Apache HttpClient调用代码：

String json = mapToJson(Map.of("name",(String)file[1],"lastname",    
(String)file[2],"createTime",(String)file[3]));
final MultipartEntityBuilder builder =                               
MultipartEntityBuilder.create();

builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
builder.addTextBody("details",json,ContentType.APPLICATION_JSON);
builder.addBinaryBody("file",(File)file[4],ContentType.APPLICATION_OCTET_STREAM,((File)file[4]).getName());

final HttpPost httpPost = new HttpPost("http://"+host+":"+port+"/api/v1/upload/");
try(CloseableHttpClient client = HttpClientBuilder.create().build()) {

    final HttpEntity entity = builder.build();
    httpPost.setEntity(entity);
    HttpResponse httpResponse = client.execute(httpPost);

    System.out.println(httpResponse);

} catch (IOException e) {
    throw new RuntimeException(e);
}

解决方案 #

原本代码中设置了builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);，调试发现Spring端接收的请求存在异常——details部分的content-type为null，导致Spring无法正确识别该部分的JSON类型，从而抛出不支持的媒体类型错误。

将Multipart模式切换为builder.setMode(HttpMultipartMode.STRICT);后，request.getParts()中的details部分会正确携带application/json类型标识，Spring能够正常解析请求，问题解决。

内容的提问来源于stack exchange，提问作者Filip Cacic