Spring无法处理“Multipart/Form-Data”POST请求（错误400“错误请求”）

Question

@RequestMapping(method = RequestMethod.POST, consumes = { "application/json" })
public ResponseEntity<String> addQuestion(@RequestBody String dtoObject) { ... }

但如果我将请求更改为“multipart/form-data”-春回错误400“bad request”：

@RequestMapping(method = RequestMethod.POST, consumes = { "multipart/form-data" })
public ResponseEntity<String> addQuestion(@RequestBody String dtoObject) { ... }

为什么？也许我应该创造一些额外的豆子？

PS：我需要“multipart/form-data”来与json对象一起发送文件。

Answer 1

我认为您不能将文件反序列化到请求正文中的dtoObject。您将需要使用@RequestPart来完成此操作。

@RequestMapping(method = RequestMethod.POST, consumes = { "multipart/form-data" })
public ResponseEntity<String> addQuestion2(@RequestPart("question") QuestionPostDto dtoObject, @RequestPart("file") MultiPartFile file)  { ... }

您的请求需要是FormData：使用您想要上传的文件和json格式文件Question.json

下面是我从《邮递员》中获得的有效载荷示例

Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW

------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="QLbLFIR.gif"
Content-Type: image/gif


------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="question"; filename="question.json"
Content-Type: application/json


------WebKitFormBoundary7MA4YWxkTrZu0gW--

@RequestMapping(method = RequestMethod.POST, consumes = { "multipart/form-data" })
    public ResponseEntity<String> addQuestion2(String question, @RequestPart("file") MultiPartFile file)  {
    QuestionPostDto dtoObject = new ObjectMapper().readValue(request, QuestionPostDto.class); 
    // do sth
}

Content-Type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW

------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="file"; filename="QLbLFIR.gif"
Content-Type: image/gif


------WebKitFormBoundary7MA4YWxkTrZu0gW
Content-Disposition: form-data; name="request"

{
    "key": "value"
}
------WebKitFormBoundary7MA4YWxkTrZu0gW--