HttpClient无乱码

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

    public static String doPost(String url, String json) {
        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpPost post = new HttpPost(url);
        String result = "";
        try {
            StringEntity s = new StringEntity(json,"utf-8");
            s.setContentEncoding("UTF-8");
            s.setContentType("application/json");//设置contentType
            post.addHeader("Content-Type", "application/json;charset=UTF-8");
            post.setEntity(s);
            HttpResponse res = httpclient.execute(post);
            if (res.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
                HttpEntity entity = res.getEntity();
                result = EntityUtils.toString(res.getEntity());
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
        return result;
    }