Java使用RestTemplate發送文件

/**
 * 發送數據到雲端接口
 *  @param filename     文件名
 */
public void sendDataToCloudApi(String filepath) {
    FileSystemResource fileSystemResource = new FileSystemResource(new File(filepath));
    // headers參數
    HttpHeaders requestHeaders = new HttpHeaders();
    // body體參數
    MultiValueMap<String, Object> requestBody = new LinkedMultiValueMap<>();
    // 設置header是文件上傳
    requestHeaders.setContentType(MediaType.MULTIPART_FORM_DATA);
    // 參數設置文件
    requestBody.add("file", fileSystemResource);
    // 封裝所有參數
    HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(requestBody, requestHeaders);
    // 創建RestTemplate
    RestTemplate restTemplate = new RestTemplate();
    // 發起請求
    JSONObject body = restTemplate.exchange("http://192.168.10.221:8301/nag/equipEvent/push/event", HttpMethod.POST,requestEntity, JSONObject.class).getBody();
    requestBody.clear();
    requestHeaders.clear();
}