[Java] 자바 1.8 에서 https SSL, TLS 연결 및 응답 소스

자바 1.8 환경에서 HTTPS로 연결하고 응답을 받아오는 가장 기본적인 코드를 아래에 소개합니다. 이 코드는 표준 라이브러리만 사용하며, 외부 라이브러리 없이 HTTPS 요청과 응답을 처리할 수 있습니다.

 

1. Hostname 검증 무시

2. 사설 인증서 무시

3. TLSv1.2 사용 (Java 8.0 이상)

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.SSLSession;
import java.security.cert.X509Certificate;

public class SslPostRequest {
    public static void main(String[] args) {
        String httpsUrl = "https://example.com/api/test";
        String jsonInput = "{\"key\": \"value\"}";

        try {
            // 사설 인증서 무시하는 TrustManager
            TrustManager[] trustAllCerts = new TrustManager[] {
                new X509TrustManager() {
                    public void checkClientTrusted(X509Certificate[] chain, String authType) {}
                    public void checkServerTrusted(X509Certificate[] chain, String authType) {}
                    public X509Certificate[] getAcceptedIssuers() { return new X509Certificate[0]; }
                }
            };

            // SSL 설정
            SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
            sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
            SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();

            // 호스트명 검증 무시
            HttpURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() {
                public boolean verify(String hostname, SSLSession session) {
                    return true;
                }
            });

            URL url = new URL(httpsUrl);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setSSLSocketFactory(sslSocketFactory);
            connection.setRequestMethod("POST");
            connection.setRequestProperty("Content-Type", "application/json; utf-8");
            connection.setRequestProperty("Accept", "application/json");
            connection.setDoOutput(true);

            try (OutputStream os = connection.getOutputStream()) {
                byte[] input = jsonInput.getBytes("utf-8");
                os.write(input, 0, input.length);
            }

            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);

            try (BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream(), "utf-8"))) {
                StringBuilder response = new StringBuilder();
                String responseLine;
                while ((responseLine = br.readLine()) != null) {
                    response.append(responseLine.trim());
                }
                System.out.println("Response: " + response.toString());
            }

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