带有 Spring 的多部分文件 http 请求 Rest 模板到达时没有文件

Question

我有这个客户端，用于使用 Rest 模板发送多部分文件 http 请求

    @Component
    public class RestTemplatePost {

        @Bean
        public RestTemplate restTemplate() {
            return new RestTemplate();
        }

        @PostConstruct
        public void prepareMessage() throws Exception {

            File file = new File("****");
            File file2 = new File("****");

            HttpHeaders httpHeaders = new HttpHeaders();
            httpHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);

            MultiValueMap<String, Object> form = new LinkedMultiValueMap<>();


            form.add("files", file);
            form.add("files", file2);
            form.add("usertoken", "test");
            form.add("sendTo", "test);
            form.add("subject", "test");
            form.add("content", "test");

            HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(form, httpHeaders);

            String serverUrl = "http://localhost:8080/api/mails/send";

            List<HttpMessageConverter<?>> httpMessageConverters = new ArrayList<>();
            httpMessageConverters.add(new FormHttpMessageConverter());
            httpMessageConverters.add(new MappingJackson2HttpMessageConverter());

            restTemplate().setMessageConverters(httpMessageConverters);


            restTemplate().postForEntity(serverUrl, requestEntity, String.class);


        }
}

然后我有这个服务器端应该接收请求：

@RestController
@RequestMapping("/api")
public class MainConroller {

    private static final Logger log = LoggerFactory.getLogger(MainConroller.class);
    @Autowired
    private MainService mainService;

    public MainConroller(MainService mainService) {
        this.mainService = mainService;
    }

    @PostMapping("/mails/send")
    public  void send(
            @RequestParam("usertoken") String usertoken,
            @RequestParam("sendTo") String sendTo,
            @RequestParam("subject") String subject,
            @RequestParam("content") String content,
            @RequestParam(required = false, name = "files") List<MultipartFile> multipartFiles) {
        log.debug("{}, {}, {}, {}", usertoken, sendTo, subject, content);

        mainService.processMessage(usertoken, sendTo, subject, content, multipartFiles);

    }
}

当我从客户端发送此请求时，除文件外，所有内容都到达了服务器端。

收到请求后RequestParam文件为空。

更新按照建议明确删除了消息转换器，没有任何改变。

Answer 1

没有文件被发送，因为没有 HttpMessageConverter 能够转换 java.io.File。另一方面，有一个 ResourceHttpMessageConverter which converts all kinds of Resource, including FileSystemResource.

PS FormHttpMessageConverter 在创建 RestTemplate 时默认添加，FormHttpMessageConverter 也在后台使用它。

带有 Spring 的多部分文件 http 请求 Rest 模板到达时没有文件

Multipart files http request with Spring Rest Template arrives without the files

java

messaging

spring

httprequest

resttemplate