在srpingboot 1.3.7中，当处理multipartform-data请求时，文件总是空的。

Question

我正在尝试将一个grails应用程序与一个springboot应用程序进行通信。我试图上传一个文件到springboot应用程序，该文件之前已经上传到了grails。

@ResponseBody
    @PostMapping(value = "/save", consumes = MediaType.MULTIPART_FORM_DATA_VALUE)
    def save(@Valid @ModelAttribute SaveRequest request) {
        //Some logic
}

saveRequest类包含了一些需要应用到请求中的验证。

class SaveHotelAccreditationRequest {

    //Other fields

    @NotNull
    MultipartFile image

}

我在application.properties文件中设置了如下属性。

spring.http.multipart.enabled = true
spring.http.multipart.location=/home/user/temp

我使用的是Apache的commons-io和commons-fileupload两个库，我把多部分解析器设置成这样。

@Bean(name = "multipartResolver")
public CommonsMultipartResolver multipartResolver() {
    CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
    multipartResolver.setMaxUploadSize(2*1024*1024);
    return multipartResolver;
}

这是我的grails应用程序中的代码

CredentialsProvider credsProvider = new BasicCredentialsProvider()
    credsProvider.setCredentials(
            AuthScope.ANY,
            new UsernamePasswordCredentials(userName, password))
    CloseableHttpClient httpclient = HttpClients.custom()
            .setDefaultCredentialsProvider(credsProvider)
            .build()
    try {
        HttpPost httpPost = new HttpPost(url)
        MultipartEntityBuilder reqEntity = MultipartEntityBuilder.create()
        reqEntity.setMode(HttpMultipartMode.BROWSER_COMPATIBLE)
        reqEntity.addBinaryBody('image', file, ContentType.MULTIPART_FORM_DATA, file.getName())
        //Other fields
        httpPost.setEntity(reqEntity.build())
        System.out.println("Executing request " + httpPost.getRequestLine())
        CloseableHttpResponse response = httpclient.execute(httpPost)
        try {
            System.out.println("----------------------------------------")
            System.out.println(response.getStatusLine())
            System.out.println(EntityUtils.toString(response.getEntity()))
        } finally {
            response.close()
        }
    } finally {
        httpclient.close()
    }

当我运行请求时，我得到以下错误信息。

2020-05-02 02:37:24 | WARN | org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver - Resolved
 exception caused by Handler execution: org.springframework.validation.BindException: org.springframework.validatio
n.BeanPropertyBindingResult: 1 errors
Field error in object 'saveHotelAccreditationRequest' on field 'image': rejected value [null]; codes [NotNull.saveRequest.image,NotNull.image,NotNull.org.springframework.web.multipart.MultipartFile,NotNull]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [saveRequest.image,image]; arguments []; default message [image]]; default message [may not be null]

我试过用postman，也得到同样的错误信息. 我不知道我在这里遗漏了什么，希望得到任何帮助。

Answer 1

在Spring-Boot REST的多部分API中，我正在写我的多部分API，就像这样。

@PostMapping("/upload-doc")
@ApiImplicitParam(paramType = "body", name = "payload", dataType = "UploadDocRequest")
@ResponseStatus(HttpStatus.CREATED)
@ApiOperation("Upload User's documents")
public UploadDocRequest uploadDocRequest(
        @RequestPart("payload") UploadDocRequest payload, @RequestPart("docs") MultipartFile[] docs) {

在yaml中配置Spring Multipart

spring:
 servlet:
  multipart:
   max-file-size: 5MB
   max-request-size: 5MB

以及如何从PostMan调用它-

Answer 2

在使用Multipart时，我在Spring启动时使用了下面的方法。

@PostMapping(value = "/uploadVideo")
public void uploadVideo(HttpServletRequest request, HttpServletResponse response,
            @RequestParam("file") MultipartFile file) throws Exception {
    // logic here
}

你所使用的最大尺寸的多部分解析器可以在属性文件中配置，如下所示

# Max file size.
spring.servlet.multipart.max-file-size=200MB
# Max Request Size
spring.servlet.multipart.max-request-size=215MB

我从Angular App中调用的这个是这样的

var reqHeader=new HttpHeaders();
    reqHeader.append('contentType','multipart/form-data')
    let options = { headers: reqHeader, params: new HttpParams()
                          
                   };
    const formData = new FormData();
    formData.append('file', file )
    return this.http.post(this.url_toreadFile,formData,options)

希望能给你的实施提供一些帮助。