공공데이터포탈

package ch01;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

public class APIExplorer {

	public static void main(String[] args) throws IOException {

		// 순수 자바코드로 (클라이언트 측 코딩)
		// 준비물
		// 1. 서버측 주소 - 경로
		// http://localhost:8080/test?name=홍길동&age=20
		// http://localhost:8080/test?name=%ED%99%8D%EA%B8%B8%EB%8F%99&age=20
		StringBuilder urlBuilder = new StringBuilder(
				"http://apis.data.go.kr/B552584/UlfptcaAlarmInqireSvc/getUlfptcaAlarmInfo");
		urlBuilder.append("?" + URLEncoder.encode("serviceKey", "UTF-8")
				+ "=9fDgSkBB3xRvTRgGb3n8kZmTa2fnUnZDizBdWcQNF97fCnbgnu2essFxPqXYRlu%2BZ4tQGQauyjmZOBgdmZCK2g%3D%3D"); /*
																														 */
		urlBuilder.append("&" + URLEncoder.encode("returnType", "UTF-8") + "=" + URLEncoder.encode("json", "UTF-8"));
		urlBuilder.append("&" + URLEncoder.encode("numOfRows", "UTF-8") + "=" + URLEncoder.encode("100", "UTF-8"));
		urlBuilder.append("&" + URLEncoder.encode("pageNo", "UTF-8") + "=" + URLEncoder.encode("1", "UTF-8"));
		urlBuilder.append("&" + URLEncoder.encode("year", "UTF-8") + "=" + URLEncoder.encode("2024", "UTF-8"));
		urlBuilder.append("&" + URLEncoder.encode("itemCode", "UTF-8") + "=" + URLEncoder.encode("PM10", "UTF-8"));

		// URL 객체에서 문자열 경로 넣어서 객체 생성
		// url.openConnection() 데이터 요청 보내기 - 설정하고

		URL url = new URL(urlBuilder.toString());

		HttpURLConnection conn = (HttpURLConnection) url.openConnection();

		conn.setRequestMethod("GET"); // 서버에게 자원 요청
		conn.setRequestProperty("Content-type", "application/json");
		// 200, 실패 404, 405 
		System.out.println("Response code: " + conn.getResponseCode());
		
		// 100 ~ 500 의미 (약속) 
		BufferedReader rd;
		if (conn.getResponseCode() >= 200 && conn.getResponseCode() <= 300) {
			rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
		} else {
			rd = new BufferedReader(new InputStreamReader(conn.getErrorStream()));
		}
		
		StringBuilder sb = new StringBuilder();
		String line;
		while ((line = rd.readLine()) != null) {
			sb.append(line);
		}
		rd.close();
		conn.disconnect();
		System.out.println(sb.toString());

	} // end of main

} // end of class