遇到一种业务场景，前端上传的文件需要经过java服务转发至文件服务。期间遇到了原生HttpClient怎么使用的问题、怎么把MultipartFile怎么重新组装成Http请求发送出去的问题、文件中文名乱码问题。最后都解决了，先上代码，再讲遇到的坑
1 @Slf4j 2 @Service 3 public class FileServiceImpl implements IFileService { 4 ?5 ????@Value("${FileService.putUrl}") 6 ????private String putUrl; 7 ????@Value("${FileService.app_id}") 8 ????private String appId; 9 ????@Value("${FileService.securityKey}")10 ????private String secureKey;11 12 ????private final static String UPLOAD_RESPONSE_CODE = "error";13 ????private final static Integer UPLOAD_RESPONSE_SUCCESS = 0;14 15 16 ????@Override17 ????public String upload(MultipartFile file) {18 19 ????????int timeOut = 30000;20 ????????CloseableHttpClient httpClient = HttpClientBuilder.create().build();21 ????????HttpHost proxy = new HttpHost("127.0.0.1", 62145, "http"); //设置本地fiddler代理，方便排查问题22 ????????RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(timeOut)23 ????????????????.setConnectTimeout(timeOut).setSocketTimeout(timeOut).setProxy(proxy).build();24 ????????HttpPost httpPost = new HttpPost(putUrl);25 ????????httpPost.setConfig(requestConfig);26 ????????try {27 ????????????//BROWSER_COMPATIBLE自定义charset，RFC6532=utf-8，STRICT=iso-8859-128 ????????????//此处一定要用RFC6532，网上普遍用的BROWSER_COMPATIBLE依然会出现中文名乱码29 ????????????MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);30 ????????????//multipartEntityBuilder.setCharset(Charset.forName("UTF-8")); //此处踩坑，转发出去的filename依然为乱码31 ???????????//ContentType contentType = ContentType.create("multipart/form-data",Charset.forName("UTF-8")); //此处也是坑，转发出去的filename依然为乱码32 ????????????multipartEntityBuilder.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());33 34 ????????????multipartEntityBuilder.addTextBody("app_id", appId); //可替换成你自己需要的附加字段35 ????????????long time = System.currentTimeMillis() / 1000;36 ????????????multipartEntityBuilder.addTextBody("time", String.valueOf(time)); //可替换成你自己需要的附加字段37 ????????????String beforeSign = String.format("app_id=%s&time=%s%s", appId, time, secureKey);38 ????????????String sign = MD5Util.md5(beforeSign);39 ????????????multipartEntityBuilder.addTextBody("sign", sign); //可替换成你自己需要的附加字段40 41 ????????????HttpEntity requestEntity = multipartEntityBuilder.build();42 ????????????httpPost.setEntity(requestEntity);43 ????????????HttpResponse httpResponse = httpClient.execute(httpPost);44 ????????????int statusCode= httpResponse.getStatusLine().getStatusCode();45 ????????????if (statusCode != 200) throw new BizException(BizCode.INNER_SERVICE_ERROR, "响应状态码为：" + statusCode);46 ????????????HttpEntity responseEntity = httpResponse.getEntity();47 ????????????return getUrlString(EntityUtils.toString(responseEntity));48 ????????} catch (Exception e) {49 ????????????log.error("发送文件异常：{}", e);50 ????????????throw new BizException(BizCode.INNER_SERVICE_ERROR, "发送文件服务异常:" + e.getMessage());51 ????????} finally {52 ????????????try {53 ????????????????httpClient.close();54 ????????????} catch (IOException e) {55 ????????????????log.error("关闭httpClient异常：" + e.getMessage(), e);56 ????????????}57 ????????}58 ????}59 60 ????private String getUrlString(String jsonString) {61 ????????try{62 ????????????log.debug("解析json串："+ jsonString);63 ????????????JSONObject jsonObject = JSONObject.parseObject(jsonString);64 ????????????if (jsonObject.getInteger(UPLOAD_RESPONSE_CODE) != UPLOAD_RESPONSE_SUCCESS) {65 ????????????????log.error("文件服务返回错误：" + jsonObject.getString("data"));66 ????????????????throw new OtherServiceReturnErrorException("文件服务返回错误：" + jsonObject.getString("data"));67 ????????????}68 ????????????return ((JSONObject)jsonObject.get("data")).get("original").toString();69 ????????}catch (Exception e) {70 ????????????log.error("文件服务返回json解析错误：" + jsonString);71 ????????????throw new OtherServiceReturnErrorException("文件服务返回json解析错误：" + jsonString);72 ????????}73 74 ????}75 }特别说明及遇到的坑：
1. 这里基于tomcat进行请求转发，需要在代码中手动添加代理：
HttpHost proxy = new HttpHost("127.0.0.1", 62145, "http"); //设置本地fiddler代理，方便排查问题
RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(timeOut)
???????.setConnectTimeout(timeOut).setSocketTimeout(timeOut).setProxy(proxy).build();2. MultipartFile通过getInputStream()可以将流设置到MultipartEntityBuilder中，其中addBinaryBody里面的ContentType 和 filename必须设置，要不然后续服务读取不到这个文件流
MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);
multipartEntityBuilder.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());
3. file.getOriginalFilename()方法虽然没有乱码，但是addBinaryBody后，组装的Http请求出去总是乱码，如下图：
踩了各种坑，如为MultipartEntityBuilder设置Charset或者是手动设置ContentType，都无法解决此问题，文件名依然是上图所示乱码
后来发现在MultipartEntityBuilder中设置Mode为HttpMultipartMode.RFC6532可以完美解决这个问题，并且不再需要单独设置ContentType或Charset，因为HttpMultipartMode.RFC6532就告诉了MultipartEntityBuilder，里面的数据都要使用UTF-8进行处理，fiddler抓到的请求发现filename成功变成中文名。
done
使用HttpClient MultipartEntityBuilder 上传文件，并解决中文文件名乱码问题
原文地址：https://www.cnblogs.com/evasean/p/9368670.html