springboot之使用http发送文件

场景：
在springboot接口中，调用http发送请求将文件发送到其他服务处理。以下是发送文件代码。

RestTemplate restTemplate = new RestTemplate();
String url = "http://localhost:8080/importFile";

SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
requestFactory.setBufferRequestBody(false);
restTemplate.setRequestFactory(requestFactory);

File file = new File("C:\Cache\File\2022-08\excel.xlsx");

MultiValueMap parts = new LinkedMultiValueMap<>();
parts.add("file", new InputStreamResource(new FileInputStream(file),"test"));

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

HttpEntity> request = new HttpEntity<>(parts, headers);
ResponseEntity ret =restTemplate.exchange(url, HttpMethod.POST, request, String.class);

System.out.println(ret.getBody().toString());