RestfulAPI.java

import org.json.JSONObject;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;

public class RestfulAPI {
    public void post (String sURL, String sJSON) {
        try {
            URL url = new URL(sURL);
            HttpURLConnection con = (HttpURLConnection) url.openConnection();
            con.setConnectTimeout(5000); // 서버에 연결되는 Timeout 시간 설정
            con.setReadTimeout(5000); // InputStream 읽어 오는 Timeout 시간 설정
            // con.addRequestProperty("x-api-key", "토크값");
            con.setRequestMethod("POST");

            //json으로 message를 전달하고자 할 때
            con.setRequestProperty("Content-Type", "application/json");
            con.setDoInput(true);
            con.setDoOutput(true); //POST 데이터를 OutputStream으로 넘겨 주겠다는 설정
            con.setUseCaches(false);
            con.setDefaultUseCaches(false);
            con.setRequestProperty("Accept", "application/json");

            OutputStreamWriter wr = new OutputStreamWriter(con.getOutputStream());
            wr.write(sJSON); //json 형식의 message 전달
            wr.flush();

            StringBuilder sb = new StringBuilder();
            if (con.getResponseCode() == HttpURLConnection.HTTP_OK ||
                con.getResponseCode() == HttpURLConnection.HTTP_CREATED) {

                InputStream is = con.getInputStream();
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                byte[] byteBuffer = new byte[1024];
                byte[] byteData = null;
                int nLength = 0;
                while((nLength = is.read(byteBuffer, 0, byteBuffer.length)) != -1) {
                    baos.write(byteBuffer, 0, nLength);
                }
                byteData = baos.toByteArray();

                JSONObject responseJSON = new JSONObject(new String(byteData));
                System.out.println(responseJSON);
            } else {
                System.out.println(con.getResponseMessage());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {
        JSONObject object = new JSONObject();
        object.put("title", "test");
        object.put("body", "test");

        RestfulAPI restfulAPI = new RestfulAPI();
        restfulAPI.post("http://localhost:3001/memo", object.toString());
    }
}