HttpClient post提交multipart/form-data數據實現文件上傳

• 場景：前端提交multipart/form-data數據，由api服務A將請求轉發到api服務B。

A服務工具類方法如下：

public static Map<String, String> sendMultipartFilePost( String url, MultipartFile multipartFile, String fileParName,
                                                        Map<String, Object> params, int timeout) {
        Map<String, String> resultMap = new HashMap<String, String>();
        CloseableHttpClient httpClient = HttpClients.createDefault();
        String result = "";
        try {
            HttpPost httpPost = new HttpPost(url);
            MultipartEntityBuilder builder = MultipartEntityBuilder.create();
            builder.setCharset(java.nio.charset.Charset.forName("UTF-8"));
            builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
            String fileName = null;
            fileName = multipartFile.getOriginalFilename();
            builder.addBinaryBody(fileParName, multipartFile.getInputStream(), ContentType.MULTIPART_FORM_DATA, fileName);// 文件流
            //解決中文亂碼
            ContentType contentType = ContentType.create(HTTP.PLAIN_TEXT_TYPE, HTTP.UTF_8);
            for (Map.Entry<String, Object> entry : params.entrySet()) {
                if(entry.getValue() == null)
                    continue;
                // 類似瀏覽器表單提交，對應input的name和value
                builder.addTextBody(entry.getKey(), entry.getValue().toString(), contentType);
            }
            HttpEntity entity = builder.build();
            httpPost.setEntity(entity);
            HttpResponse response = httpClient.execute(httpPost);// 執行提交

            // 設置連接超時時間
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(timeout)
                    .setConnectionRequestTimeout(timeout).setSocketTimeout(timeout).build();
            httpPost.setConfig(requestConfig);

            HttpEntity responseEntity = response.getEntity();
            resultMap.put("scode", String.valueOf(response.getStatusLine().getStatusCode()));
            resultMap.put("data", "");
            if (responseEntity != null) {
                // 將響應內容轉換爲字符串
                result = EntityUtils.toString(responseEntity, java.nio.charset.Charset.forName("UTF-8"));
                resultMap.put("data", result);
            }
        } catch (Exception e) {
            resultMap.put("scode", "error");
            resultMap.put("data", "HTTP請求出現異常: " + e.getMessage());

            Writer w = new StringWriter();
            e.printStackTrace(new PrintWriter(w));
        } finally {
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return resultMap;
    }

控制層調用方法如下：兩種方式根據前端傳值方式自行選擇

第一種：

public BaseResponse<Object> uploadFile(@RequestParam("file") MultipartFile file,
                                           HttpServletRequest request){
        BaseResponse<Object> result = new BaseResponse<Object>();
        try {
            String code = request.getParameter("code");
            String name = request.getParameter("name");
            String url = request.getParameter("url");
            url = nlpNerPath + url;
            Map<String, Object> data = new HashMap<>();
            data.put("code", code);
            data.put("name", name);
            Map<String, String> resultDataMap = HttpRequest.sendMultipartFilePost(url, file, "file", data, -1);
            if ("200".equals(resultDataMap.get("scode"))) {
                result.code = 200;
                result.setMsg("成功");
            }
        } catch (Exception e) {
            e.printStackTrace();
            result.code = 500;
            result.setMsg("服務器錯誤");
        }
        return result;
    }

 第二種：

@RequestMapping(value = "/add", method = RequestMethod.POST)
public @ResponseBody Map<String, Object> add(HttpServletRequest request) throws Exception {
    MultipartHttpServletRequest params = ((MultipartHttpServletRequest) request);
    Map<String, Object> data = new HashMap<>();
    data.put("code", params.getParameter("code"));
    data.put("name", params.getParameter("name"));
    Map<String, String> resultDataMap = HttpUtil.httpPostRequest2("轉發API地址",params.getFiles("files"), "files", data, -1);
    if ("200".equals(resultDataMap.get("scode"))) {
        Map<String, Object> returnData = JsonUtil.reflect(MapUtil.getString(resultDataMap, "data"));
        super.setOutData(returnData);
        return returnData;
    }
}

參考博客：https://blog.csdn.net/u010826617/article/details/80236226  多文件上傳

                  https://blog.csdn.net/lsqingfeng/article/details/90611686     單文件上傳

普通的java發送http的get、post請求請參考博客：https://blog.csdn.net/QCIWYY/article/details/100503207