使用HttpClient MultipartEntityBuilder 上传文件，并解决中文文件名乱码问题

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     @Override 17     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-8859-1 28             //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

原文：https://www.cnblogs.com/evasean/p/9368670.html

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