接口前端上传的文件，然后通过httpClient发送给远程接口

需要的包

<dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.3.1</version>
        </dependency>
 
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.8</version>
        </dependency>

 

接收前端上传的文件

public String uploadProductAttachment(MultipartFile file) throws MicroException {
        if(file == null || file.isEmpty()){
            throw new MicroException(HttpStatus.BAD_REQUEST.value(), Commons.DATA_IS_NULL);
        }
        File toFile = null;
        InputStream ins = null;
        try {
            ins = file.getInputStream();
            toFile = new File(file.getOriginalFilename());
            inputStreamToFile(ins, toFile);
            JSONObject result = RestUtil.postUploadFile(baseConfig.getForwardRootUrl() + "/uploadProductAttachment", toFile);
            if(result.getIntValue("code") == OK){
                JSONObject resultData = result.getJSONObject("data");
                if(resultData != null){
                    if(resultData.getBoolean("success")){
                        JSONArray data = resultData.getJSONArray("data");
                        if(data != null && data.size() > 0){
                            JSONObject a = data.getJSONObject(0);
                            return a.getString("id");
                        }
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            LOG.error(e.getMessage());
            throw new MicroException(HttpStatus.BAD_REQUEST.value(), Commons.ERROR);
        }finally {
            if(ins != null){
                try {
                    ins.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }

public static JSONObject postUploadFile(String url, File file){
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        try {
            httpClient = HttpClients.createDefault();
            HttpPost httpPost = new HttpPost(url);
            InputStreamBody bin = new InputStreamBody(new FileInputStream(file), file.getName());
            HttpEntity reqEntity = MultipartEntityBuilder.create()
                    .setCharset(Charset.forName("UTF-8"))
                    // 相当于<input type="file" name="file"/>
                    .addPart("file", bin)
                    .build();
            httpPost.setEntity(reqEntity);
            // 发起请求 并返回请求的响应
            response = httpClient.execute(httpPost);
            return covertEntityToJSON(response.getEntity());
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if(response != null){
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(httpClient != null){
                try {
                    httpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return null;
    }