java后台调用文件上传接口

借鉴：https://blog.csdn.net/yjclsx/article/details/70675057

 /**
      * 调用流程上传文件接口上传文件
      * @param url
      * @param path
      * @return
      */
     public static String sendPostUplodFile(String url,String path) {
         DataOutputStream out = null;
         BufferedReader in = null;
         String result = "";
         try {
             URL realUrl = new URL(url);
             //打开和URL之间的连接
             HttpURLConnection conn = (HttpURLConnection)realUrl.openConnection();
             //发送POST请求必须设置如下两行
             conn.setDoOutput(true);
             conn.setDoInput(true);

             String BOUNDARY = "----WebKitFormBoundary07I8UIuBx6LN2KyY";
             conn.setUseCaches(false);
             conn.setRequestMethod("POST");
             conn.setRequestProperty("connection", "Keep-Alive");
 //            conn.setRequestProperty("user-agent", "Mozilla/4.0 (conpatible; MSIE 6.0; Windows NT 5.1; SV1)");
             conn.setRequestProperty("user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36");
             conn.setRequestProperty("Charsert", "UTF-8");
             conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + BOUNDARY);
             conn.connect();

             out = new DataOutputStream(conn.getOutputStream());
             byte[] end_data = ("\r\n--" + BOUNDARY + "--\r\n").getBytes();
             //添加参数
             StringBuffer sb1 = new StringBuffer();
             sb1.append("--");
             sb1.append(BOUNDARY);
             sb1.append("\r\n");
             sb1.append("Content-Disposition: form-data;name=\"luid\"");
             sb1.append("\r\n");
             sb1.append("\r\n");
             sb1.append("123");
             sb1.append("\r\n");
             out.write(sb1.toString().getBytes());
             //添加参数file
             File file = new File(path);
             StringBuffer sb = new StringBuffer();
             sb.append("--");
             sb.append(BOUNDARY);
             sb.append("\r\n");
             sb.append("Content-Disposition: form-data;name=\"file\";filename=\"" + file.getName() + "\"");
             sb.append("\r\n");
             sb.append("Content-Type: application/octet-stream");
             sb.append("\r\n");
             sb.append("\r\n");
             out.write(sb.toString().getBytes());

             DataInputStream in1 = new DataInputStream(new FileInputStream(file));
             int bytes = 0;
             byte[] bufferOut = new byte[1024];
             while ((bytes = in1.read(bufferOut)) != -1) {
                 out.write(bufferOut,0,bytes);
             }
             out.write("\r\n".getBytes());
             in1.close();
             out.write(end_data);

             //flush输出流的缓冲
             out.flush();
             //定义BufferedReader输入流来读取URL的响应
             in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
             String line;
             while ((line = in.readLine()) != null) {
                 result += line;
             }
         } catch (Exception e) {
             // TODO Auto-generated catch block
             log.error("发送POST请求出现异常" + e);
             e.printStackTrace();
         }finally {
             try {
                 if (out != null) {
                     out.close();
                 }
                 if (in != null) {
                     in.close();
                 }
             } catch (Exception ex) {
                 // TODO: handle exception
                 ex.printStackTrace();
             }
         }
         return result;
     }

 //将字符串转换json并取值
1 public static String getFileId(String result) {
         JSONObject json = JSONObject.parseObject(result);
         String fileId = "";
         if (result != null) {
             String code = json.getString("errorCode");
             if (code.equals("0000")) {
                 fileId = json.getString("fileId");
             }
         }

         return fileId;
     }