使用HttpClient MultipartEntityBuilder 上傳文件，並解決中文文件名亂碼問題

遇到一種業務場景，前端上傳的文件需要經過java服務轉發至文件服務。期間遇到了原生HttpClient怎么使用的問題、怎么把MultipartFile怎么重新組裝成Http請求發送出去的問題、文件中文名亂碼問題。最后都解決了，先上代碼，再講遇到的坑

@Slf4j
@Service
public class FileServiceImpl implements IFileService {

    @Value("${FileService.putUrl}")
    private String putUrl;
    @Value("${FileService.app_id}")
    private String appId;
    @Value("${FileService.securityKey}")
    private String secureKey;

    private final static String UPLOAD_RESPONSE_CODE = "error";
    private final static Integer UPLOAD_RESPONSE_SUCCESS = 0;


    @Override
    public String upload(MultipartFile file) {

        int timeOut = 30000;
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        HttpHost proxy = new HttpHost("127.0.0.1", 62145, "http"); //設置本地fiddler代理，方便排查問題
        RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(timeOut)
                .setConnectTimeout(timeOut).setSocketTimeout(timeOut).setProxy(proxy).build();
        HttpPost httpPost = new HttpPost(putUrl);
        httpPost.setConfig(requestConfig);
        try {
            //BROWSER_COMPATIBLE自定義charset，RFC6532=utf-8，STRICT=iso-8859-1
            //此處一定要用RFC6532，網上普遍用的BROWSER_COMPATIBLE依然會出現中文名亂碼
            MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);
            //multipartEntityBuilder.setCharset(Charset.forName("UTF-8")); //此處踩坑，轉發出去的filename依然為亂碼
           //ContentType contentType = ContentType.create("multipart/form-data",Charset.forName("UTF-8")); //此處也是坑，轉發出去的filename依然為亂碼
            multipartEntityBuilder.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());

            multipartEntityBuilder.addTextBody("app_id", appId); //可替換成你自己需要的附加字段
            long time = System.currentTimeMillis() / 1000;
            multipartEntityBuilder.addTextBody("time", String.valueOf(time)); //可替換成你自己需要的附加字段
            String beforeSign = String.format("app_id=%s&time=%s%s", appId, time, secureKey);
            String sign = MD5Util.md5(beforeSign);
            multipartEntityBuilder.addTextBody("sign", sign); //可替換成你自己需要的附加字段

            HttpEntity requestEntity = multipartEntityBuilder.build();
            httpPost.setEntity(requestEntity);
            HttpResponse httpResponse = httpClient.execute(httpPost);
            int statusCode= httpResponse.getStatusLine().getStatusCode();
            if (statusCode != 200) throw new BizException(BizCode.INNER_SERVICE_ERROR, "響應狀態碼為：" + statusCode);
            HttpEntity responseEntity = httpResponse.getEntity();
            return getUrlString(EntityUtils.toString(responseEntity));
        } catch (Exception e) {
            log.error("發送文件異常：{}", e);
            throw new BizException(BizCode.INNER_SERVICE_ERROR, "發送文件服務異常:" + e.getMessage());
        } finally {
            try {
                httpClient.close();
            } catch (IOException e) {
                log.error("關閉httpClient異常：" + e.getMessage(), e);
            }
        }
    }

    private String getUrlString(String jsonString) {
        try{
            log.debug("解析json串："+ jsonString);
            JSONObject jsonObject = JSONObject.parseObject(jsonString);
            if (jsonObject.getInteger(UPLOAD_RESPONSE_CODE) != UPLOAD_RESPONSE_SUCCESS) {
                log.error("文件服務返回錯誤：" + jsonObject.getString("data"));
                throw new OtherServiceReturnErrorException("文件服務返回錯誤：" + jsonObject.getString("data"));
            }
            return ((JSONObject)jsonObject.get("data")).get("original").toString();
        }catch (Exception e) {
            log.error("文件服務返回json解析錯誤：" + jsonString);
            throw new OtherServiceReturnErrorException("文件服務返回json解析錯誤：" + jsonString);
        }

    }
}

特別說明及遇到的坑：

1. 這里基於tomcat進行請求轉發，需要在代碼中手動添加代理：

HttpHost proxy = new HttpHost("127.0.0.1", 62145, "http"); //設置本地fiddler代理，方便排查問題
RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(timeOut)
        .setConnectTimeout(timeOut).setSocketTimeout(timeOut).setProxy(proxy).build();

2. MultipartFile通過getInputStream()可以將流設置到MultipartEntityBuilder中，其中addBinaryBody里面的ContentType 和 filename必須設置，要不然后續服務讀取不到這個文件流

MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);
multipartEntityBuilder.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());

3. file.getOriginalFilename()方法雖然沒有亂碼，但是addBinaryBody后，組裝的Http請求出去總是亂碼，如下圖：

 

踩了各種坑，如為MultipartEntityBuilder設置Charset或者是手動設置ContentType，都無法解決此問題，文件名依然是上圖所示亂碼

后來發現在MultipartEntityBuilder中設置Mode為HttpMultipartMode.RFC6532可以完美解決這個問題，並且不再需要單獨設置ContentType或Charset，因為HttpMultipartMode.RFC6532就告訴了MultipartEntityBuilder，里面的數據都要使用UTF-8進行處理，fiddler抓到的請求發現filename成功變成中文名。

 

 

done