HttpUtil.java

package th.util;

import java.io.IOException;
import java.util.Map;

import org.apache.http.HttpEntity;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
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;

import com.google.gson.Gson;

public class HttpUtil {

	private final static String CONTENT_TYPE_TEXT_JSON = "text/json";

	public static String postRequest(String url, Map<String, Object> param) throws ClientProtocolException, IOException{

		CloseableHttpClient client = HttpClients.createDefault();

		HttpPost httpPost = new HttpPost(url);
		httpPost.setHeader("Content-Type", "application/json;charset=UTF-8");

		Gson gson = new Gson();
		String parameter = gson.toJson(param);

		StringEntity se = new StringEntity(parameter);
		se.setContentType(CONTENT_TYPE_TEXT_JSON);
		httpPost.setEntity(se);

		CloseableHttpResponse response = client.execute(httpPost);
		HttpEntity entity = response.getEntity();
		String result = EntityUtils.toString(entity, "UTF-8");

		return result;
	}
}