[JAVA] HttpURLConnection GET/POST 방식

HttpURLConnection.java
1. GET 방식
2. POST 방식 

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.Map;

import org.json.simple.JSONObject;

public class HttpConnectionUtils {
	
	/** HttpURLConnection GET 방식 */
	public static String getRequest(String targetUrl) {
		
		String response = "";
		
		try {
			
			URL url = new URL(targetUrl);
			HttpURLConnection conn = (HttpURLConnection) url.openConnection();
			conn.setRequestMethod("GET"); // 전송 방식
			conn.setRequestProperty("Content-Type", "application/json; charset=utf-8");
			conn.setConnectTimeout(5000); // 연결 타임아웃 설정(5초) 
			conn.setReadTimeout(5000); // 읽기 타임아웃 설정(5초)
			conn.setDoOutput(true);
			
	        System.out.println("getContentType():" + conn.getContentType()); // 응답 콘텐츠 유형 구하기
	        System.out.println("getResponseCode():"    + conn.getResponseCode()); // 응답 코드 구하기
	        System.out.println("getResponseMessage():" + conn.getResponseMessage()); // 응답 메시지 구하기

			Charset charset = Charset.forName("UTF-8");
			BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(), charset));
			
			String inputLine;			
			StringBuffer sb = new StringBuffer();
			while ((inputLine = br.readLine()) != null) {
				sb.append(inputLine);
			}
			br.close();
			
			response = sb.toString();
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		return response;
	}
	
	/** HttpURLConnection POST 방식 */
	public static String postRequest(String targetUrl, Map<String, Object> requestMap) {

		String response = "";

		try {

			URL url = new URL(targetUrl);
			HttpURLConnection conn = (HttpURLConnection) url.openConnection();
			conn.setRequestMethod("POST"); // 전송 방식
			conn.setRequestProperty("Content-Type", "application/json; charset=utf-8");
			conn.setConnectTimeout(5000); // 연결 타임아웃 설정(5초) 
			conn.setReadTimeout(5000); // 읽기 타임아웃 설정(5초)
			conn.setDoOutput(true);	// URL 연결을 출력용으로 사용(true)
			
			String requestBody = getJsonStringFromMap(requestMap);
			System.out.println("requestBody:" + requestBody);
			
			BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(conn.getOutputStream()));
			bw.write(requestBody);
			bw.flush();
			bw.close();

			System.out.println("getContentType():" + conn.getContentType()); // 응답 콘텐츠 유형 구하기
	        System.out.println("getResponseCode():"    + conn.getResponseCode()); // 응답 코드 구하기
	        System.out.println("getResponseMessage():" + conn.getResponseMessage()); // 응답 메시지 구하기

			Charset charset = Charset.forName("UTF-8");
			BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream(), charset));
			
			String inputLine;			
			StringBuffer sb = new StringBuffer();
			while ((inputLine = br.readLine()) != null) {
				sb.append(inputLine);
			}
			br.close();
			
			response = sb.toString();

		} catch (Exception e) {
			e.printStackTrace();
		}

		return response;
	}
	
	/** Map을 jsonString으로 변환 */
	@SuppressWarnings("unchecked")
	public static String getJsonStringFromMap(Map<String, Object> map) {
    
		JSONObject json = new JSONObject();
		
		for(Map.Entry<String, Object> entry : map.entrySet()) {
			
			String key = entry.getKey();
            Object value = entry.getValue();
            
            json.put(key, value);
        }
        
        return json.toJSONString();
	}
}

 

HttpConnectionUtilsTest.java

import java.util.HashMap;
import java.util.Map;

import org.junit.Test;

public class HttpConnectionUtilsTest {

	@Test
	public void testGetRequest() {
		
		String url = "https://jsonplaceholder.typicode.com/posts/1";
				
		String response = HttpConnectionUtils.getRequest(url);
		System.out.println("getRequest:" + response);
	}

	@Test
	public void testPostRequest() {
		
		String url = "https://jsonplaceholder.typicode.com/posts";
		
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("title", "foo");
		map.put("body", "bar");
		map.put("userId", 1);
				
		String response = HttpConnectionUtils.postRequest(url, map);
		System.out.println("postRequest:" + response);
	}
}