HttpClient的Post请求map参数的转换

记一个HttpClient创建Post请求，如何将Map参数转成StringEntity

public static JSONObject doPost(String url, Map<String, Object> params) throws Exception {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            HttpPost httpPost = new HttpPost(url);
            // 设置请求头为JSON
            httpPost.setHeader("Content-Type", "application/json");

            // 将Map转换为JSON字符串
            ObjectMapper objectMapper = new ObjectMapper();
            String json = objectMapper.writeValueAsString(params);
            // 设置请求体
            httpPost.setEntity(new StringEntity(json, StandardCharsets.UTF_8));
            CloseableHttpResponse response = httpClient.execute(httpPost);
            try {
                int statusCode = response.getStatusLine().getStatusCode();
                if (statusCode == 200) {
                    HttpEntity responseEntity = response.getEntity();
                    if (responseEntity!= null) {
                        String result = EntityUtils.toString(responseEntity);
                        return JSON.parseObject(result);
                    }
                } else {
                    throw new BusinessException("上传失败");
                }
            } finally {
                response.close();
            }
        } catch (Exception e) {
            throw e;
        } finally {
            httpClient.close();
        }
        throw new BusinessException("上传失败");
    }