Springboot从URL获取数据流并写入httpRespon

//获取输入流
public static InputStream getInputStream() {
        InputStream inputStream = null;
        HttpURLConnection httpURLConnection = null;
        try {
            URL url = new URL("http://10.110.200.157:8080/services/attachment/file/download/AttachmentDownload?id=2429");
            httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setConnectTimeout(3000);
            httpURLConnection.setDoInput(true);
            httpURLConnection.setRequestMethod("GET");
            int responseCode = httpURLConnection.getResponseCode();
            if (responseCode == 200) {
                inputStream = httpURLConnection.getInputStream();
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return inputStream;
    }

//测试：写接口将输入流写入httpResponse
@GET
    @Path(value = "/findFile/{id}")
    @Operation(code = Operation.READ, desc = Operation.READ_DESC)
    public String findFile(@PathParam("id") Long id) throws BusinessAccessException {

        String url = "http://10.110.200.157:8080/services/attachment/file/download/AttachmentDownload?id=2429";
        ServletOutputStream outputStream = null;
        InputStream decryptInputStream = getInputStream();
        try{
            httpResponse.reset();
            outputStream = httpResponse.getOutputStream();
            // 在http响应中输出流
            byte[] cache = new byte[1024];
            int nRead = 0;
            while ((nRead = decryptInputStream.read(cache)) != -1) {
                outputStream.write(cache, 0, nRead);
                outputStream.flush();
            }
            outputStream.flush();
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }