Java微信小程序消息模板中文乱码

public static String postSSL(String url, Map<String, Object> json) {
    CloseableHttpClient httpClient = null;
    HttpPost httpPost = null;
    String result = "";
    try {
        httpClient = (CloseableHttpClient) wrapClient();
        RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(4000).setConnectTimeout(4000).build();
        httpPost = new HttpPost(url);
        httpPost.setConfig(requestConfig);
        httpPost.setHeader("Content-Type","application/json;charset=utf-8");
       // httpPost.setHeader("Accept-Charset","utf-8");
        System.out.println(JSON.toJSONString(json));
        StringEntity entity=new StringEntity(JSON.toJSONString(json),"utf-8");//解决中文乱码
        entity.setContentEncoding("utf-8");
        //entity.setContentEncoding();
        httpPost.setEntity(entity);
        CloseableHttpResponse response = httpClient.execute(httpPost);
        HttpEntity httpEntity = response.getEntity();

        result = EntityUtils.toString(httpEntity, "UTF-8");

    } catch (ClientProtocolException e) {
        result = "";
    } catch (IOException e) {
        result = "";
    } finally {
        try {
            if (httpPost != null) {
                httpPost.releaseConnection();
            }
            if (httpClient != null) {
                httpClient.close();
            }
        } catch (IOException e) {
            result = "";
        }
    }
    return result;
}