java后台调用下载文件接口获取文件名文件流并且下载文件

       JSONObject datatokenJson = new JSONObject();//data域
       datatokenJson.put("gridFsId", "607f90ab0e72467a7bd1328b");
       String jsonStr = JSONObject.toJSONString(datatokenJson);                
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost post = new HttpPost("http://192.168.28.130:8080/supportingPlatformTygn/unstructured/download/gridFsId");
        StringEntity postEntity = new StringEntity(jsonStr, "UTF-8");
        post.setEntity(postEntity);
        //设置消息头
        post.setHeader(new BasicHeader("Content-Type", "application/json"));
        post.setHeader(new BasicHeader("Accept", "application/json"));
        post.setHeader(new BasicHeader("apptoken", "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJqdGkiOiI1ODQ0NTIxYy0xZjA5LTRkODctODA0Mi0zMWI2ODc5YzQyY2MiLCJpYXQiOjE2MTc3ODM0MjgsImlzcyI6InVzZXIiLCJ1c2VySWQiOiI0MDI4ODMzMTc1NGEyYTc1MDE3NTRhYTZhYzY1MDAyNCJ9.RMZ59r9XFeUpRGQ48_bZlivnHFyOfj20zEG2KcDBOy0"));
        HttpResponse response = null;
        try {
            response = httpClient.execute(post);
            // 获取header中文件名称
            String fileName = "";int x=0;
            try {
               Header[] headers = response.getAllHeaders();
               for(int i=0;i<headers.length;i++) {
                       System.out.println(response.getAllHeaders()[i].getValue());                      
                       if(response.getAllHeaders()[i].getValue().indexOf("filename")!=-1) {
                               x=i;
                       }
               }
               fileName = response.getAllHeaders()[x].getValue().split(";")[1].split("=")[1]; 
               if (httpServletRequest.getHeader("User-Agent").toUpperCase().indexOf("MSIE") < 0){
                       fileName = new String(fileName.getBytes("ISO8859-1"),"GBK");
                       httpServletResponse.setHeader("Content-Disposition", "attachment; filename="+  fileName);
               } else{
                       fileName = URLDecoder.decode(fileName, "UTF-8");
                       fileName = new String(fileName.getBytes("ISO8859-1"),"UTF-8");
                       httpServletResponse.setHeader("Content-Disposition", "attachment; filename="+ fileName);//IE浏览器
               }
               httpServletResponse.setContentType("application/octet-stream");
               System.out.println(fileName);             
            } catch (Exception e) {
            }            
             // 后去接口返回的文件流
            HttpEntity entity1 = response.getEntity();
            BufferedInputStream br = new BufferedInputStream(entity1.getContent());
            byte[] buf = new byte[1024];
            int len = 0;
            // 要写入本地的文件
    //            FileOutputStream fileOutputStream = new FileOutputStream("D:/WorkFile/xinchuang/" + fileName);
            OutputStream fileOutputStream = httpServletResponse.getOutputStream();
            while ((len = br.read(buf)) != -1) {
                fileOutputStream.write(buf, 0, len);
            }
            fileOutputStream.close();
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
    //                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }