java调用远端接口进行文件上传

代码：

public static String uploadFile(String url, File file) throws ClientProtocolException, IOException {
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        CloseableHttpResponse httpResponse = null;
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(200000).setSocketTimeout(200000000).build();
        HttpPost httpPost = new HttpPost(url);
        httpPost.setConfig(requestConfig);
        MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
        //multipartEntityBuilder.setCharset(Charset.forName("UTF-8"));

        //File file = new File("F:\\Ken\\1.PNG");
        //FileBody bin = new FileBody(file);


        //multipartEntityBuilder.addBinaryBody("file", file,ContentType.create("image/png"),"abc.pdf");
        //当设置了setSocketTimeout参数后，以下代码上传PDF不能成功，将setSocketTimeout参数去掉后此可以上传成功。上传图片则没有个限制
        //multipartEntityBuilder.addBinaryBody("file",file,ContentType.create("application/octet-stream"),"abd.pdf");
        multipartEntityBuilder.addBinaryBody("file", file);
        //multipartEntityBuilder.addPart("comment", new StringBody("This is comment", ContentType.TEXT_PLAIN));
        multipartEntityBuilder.addTextBody("comment", "this is comment");
        HttpEntity httpEntity = multipartEntityBuilder.build();
        httpPost.setEntity(httpEntity);

        httpResponse = httpClient.execute(httpPost);
        HttpEntity responseEntity = httpResponse.getEntity();
        int statusCode = httpResponse.getStatusLine().getStatusCode();
        if (statusCode == 200) {
            BufferedReader reader = new BufferedReader(new InputStreamReader(responseEntity.getContent()));
            StringBuffer buffer = new StringBuffer();
            String str = "";
            while (!StringUtils.isEmpty(str = reader.readLine())) {
                buffer.append(str);
            }
            System.out.println(buffer.toString());
            return buffer.toString();
        }

        httpClient.close();
        if (httpResponse != null) {
            httpResponse.close();
        }
        return null;
    }