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

刺骨的言语ヽ痛彻心扉 2022-12-25 08:52 299阅读 0赞

## 写在前面 ##

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

## 正文 ##

@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"); //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();
            HttpPost httpPost = new HttpPost(putUrl);
            httpPost.setConfig(requestConfig);
            try { 
                //BROWSER_COMPATIBLE自定义charset，RFC6532=utf-8，STRICT=iso-8859-1
                //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
                MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);
                //multipartEntityBuilder.setCharset(Charset.forName("UTF-8")); //此处踩坑，转发出去的filename依然为乱码
               //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
                multipartEntityBuilder.addBinaryBody("file", file.getInputStream(), ContentType.DEFAULT_BINARY, file.getOriginalFilename());
    
                multipartEntityBuilder.addTextBody("app_id", appId); //可替换成你自己需要的附加字段
                long time = System.currentTimeMillis() / 1000;
                multipartEntityBuilder.addTextBody("time", String.valueOf(time)); //可替换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); //可替换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, "响应状态码为：" + statusCode);
                HttpEntity responseEntity = httpResponse.getEntity();
                return getUrlString(EntityUtils.toString(responseEntity));
            } catch (Exception e) { 
                log.error("发送文件异常：{}", e);
                throw new BizException(BizCode.INNER_SERVICE_ERROR, "发送文件服务异常:" + e.getMessage());
            } finally { 
                try { 
                    httpClient.close();
                } catch (IOException e) { 
                    log.error("关闭httpClient异常：" + 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("文件服务返回错误：" + jsonObject.getString("data"));
                    throw new OtherServiceReturnErrorException("文件服务返回错误：" + jsonObject.getString("data"));
                }
                return ((JSONObject)jsonObject.get("data")).get("original").toString();
            }catch (Exception e) { 
                log.error("文件服务返回json解析错误：" + jsonString);
                throw new OtherServiceReturnErrorException("文件服务返回json解析错误：" + jsonString);
            }
    
        }
    }

## 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：

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Fpd2FzdG9u_size_16_color_FFFFFF_t_70]

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。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2Fpd2FzdG9u_size_16_color_FFFFFF_t_70 1]

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