java代码发送JSON格式的httpPOST请求

package com.test;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import net.sf.json.JSONObject;

public class AppAddTest {

	public static final String ADD_URL = "http://localhost:16000/app/add";

	public static void appadd() {

		try {
			//创建连接
			URL url = new URL(ADD_URL);
			HttpURLConnection connection = (HttpURLConnection) url
					.openConnection();
			connection.setDoOutput(true);
			connection.setDoInput(true);
			connection.setRequestMethod("POST");
			connection.setUseCaches(false);
			connection.setInstanceFollowRedirects(true);
			connection.setRequestProperty("Content-Type",
					"application/x-www-form-urlencoded");

			connection.connect();

			//POST请求
			DataOutputStream out = new DataOutputStream(
					connection.getOutputStream());
			JSONObject obj = new JSONObject();
			obj.element("app_name", "asdf");
			obj.element("app_ip", "10.21.243.234");
			obj.element("app_port", 8080);
			obj.element("app_type", "001");
			obj.element("app_area", "asd");

			out.writeBytes(obj.toString());
			out.flush();
			out.close();

			//读取响应
			BufferedReader reader = new BufferedReader(new InputStreamReader(
					connection.getInputStream()));
			String lines;
			StringBuffer sb = new StringBuffer("");
			while ((lines = reader.readLine()) != null) {
				lines = new String(lines.getBytes(), "utf-8");
				sb.append(lines);
			}
			System.out.println(sb);
			reader.close();
			// 断开连接
			connection.disconnect();
		} catch (MalformedURLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

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

}