post請求返回數據中包含文件

最近在工作中遇到一個需求，post請求查詢某個業務記錄，返回的數據中除包含該記錄的基本信息外，還包含一個PDF文件。調用post請求後，需要將返回結果保存到數據庫中，同時將PDF文件存到本地硬盤。經過一番嘗試，解決了此需求，現將代碼分享出來：

客戶端代碼：

public static void main(String[] args) {
        httpPost();
    }

    public static void httpPost() {
        JSONObject paramJson = new JSONObject();
        int timeout = 60000; // 超時時間60s
        CloseableHttpClient httpClient = HttpClients.createDefault();
        RequestConfig defaultRequestConfig = RequestConfig.custom().setConnectTimeout(timeout)
                .setConnectionRequestTimeout(timeout).setSocketTimeout(timeout).build();

        HttpPost httpPost = null;
        List<NameValuePair> nvps = null;
        CloseableHttpResponse response = null;
        HttpEntity resEntity = null;
        try {
            httpPost = new HttpPost("http://localhost:8090/invoice/queryInvoice");
            httpPost.setConfig(defaultRequestConfig);
            paramJson.put("busNo", "123456");
            httpPost.setEntity(new StringEntity(JSON.toJSONString(paramJson), Consts.UTF_8));

            response = httpClient.execute(httpPost);
            resEntity = response.getEntity();
            String resStr = EntityUtils.toString(resEntity, Consts.UTF_8);
            EntityUtils.consume(resEntity);
            JSONObject result = JSONObject.parseObject(resStr);
            byte[] pdfFile = result.getBytes("pdfFile");
            saveFile(pdfFile, "D:\\pdfFiles", "123456.pdf");
        } catch (UnsupportedEncodingException e) {
            throw new BizException(e);
        } catch (ClientProtocolException e) {
            throw new BizException(e);
        } catch (SocketTimeoutException e) {
            throw new BizException("調用服務超時", e);
        } catch (ConnectTimeoutException e) {
            throw new BizException("調用服務超時", e);
        } catch (IOException e) {
            throw new BizException(e);
        } finally {
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * @Author administrator
     * @Description 保存byte數組包含的文件到指定路徑
     * @Date 22:06 2019/12/22
     * @Param [bfile, filePath, fileName]
     * @return void
     **/
    public static void saveFile(byte[] bfile, String filePath, String fileName) {
        BufferedOutputStream bos = null;
        FileOutputStream fos = null;
        File file = null;
        try {
            File dir = new File(filePath);
            boolean isDir = dir.isDirectory();
            if (!isDir) {// 目錄不存在則先建目錄
                try {
                    dir.mkdirs();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            file = new File(filePath + File.separator + fileName);
            fos = new FileOutputStream(file);
            bos = new BufferedOutputStream(fos);
            bos.write(bfile);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
    }

服務端代碼：

/**
     * @Author administrator
     * @Description post請求返回結果包含文件
     * @Date 22:02 2019/12/22
     * @Param [request]
     * @return com.alibaba.fastjson.JSONObject
     **/
    @RequestMapping(method = RequestMethod.POST, path = "/queryInvoice")
    @ResponseBody
    public JSONObject queryInvoice(HttpServletRequest request) throws Exception {
        String paraStr = StreamUtils.copyToString(request.getInputStream(), StandardCharsets.UTF_8);
        JSONObject paraJson = JSONObject.parseObject(paraStr);
        String busNo = paraJson.getString("busNo");
        byte[] pdfFile = toByteArray("F:\\fapiao\\" + busNo + ".pdf");//讀取本地一個PDF文件
        JSONObject result = new JSONObject();
        result.put("busNo", "123456");
        result.put("time", "2019-10-14");
        result.put("pdfFile", pdfFile);
        return result;
    }

    /**
     * @Author administrator
     * @Description 讀取本地文件到byte數組
     * @Date 22:01 2019/12/22
     * @Param [filename]
     * @return byte[]
     **/
    public static byte[] toByteArray(String filename) throws IOException {

        File f = new File(filename);
        if (!f.exists()) {
            throw new FileNotFoundException(filename);
        }

        ByteArrayOutputStream bos = new ByteArrayOutputStream((int) f.length());
        BufferedInputStream in = null;
        try {
            in = new BufferedInputStream(new FileInputStream(f));
            int buf_size = 1024;
            byte[] buffer = new byte[buf_size];
            int len = 0;
            while (-1 != (len = in.read(buffer, 0, buf_size))) {
                bos.write(buffer, 0, len);
            }
            return bos.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
            throw e;
        } finally {
            try {
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            bos.close();
        }
    }

 經過測試，發現能夠達到預期效果。補充，有時候，可能因爲文件過大，導致文件不能正常存儲打開，這時候可以考慮採用base64在服務端對byte數組進行編碼爲字符串，客戶端接收後將字符串通過base64解碼爲byte數組再保存，問題解決。

希望該分享能對需要的朋友有所幫助，不對的地方敬請斧正。