HTTPS主要用于安全传输数据，从代码的角度来看，HTTPS主要使用了X509的方式进行了加密，至于密钥(证书)在什么地方，可能在购买HTTPS服务的时候被统一放置在DNS服务器之类的地方了吧(纯推测)：

package com.sahadev;import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.URL;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.X509TrustManager;import org.apache.http.conn.ssl.AllowAllHostnameVerifier;public class HttpClient {private static final AllowAllHostnameVerifier HOSTNAME_VERIFIER = new AllowAllHostnameVerifier();private static X509TrustManager xtm = new X509TrustManager() {public void checkClientTrusted(X509Certificate[] chain, String authType) {}public void checkServerTrusted(X509Certificate[] chain, String authType) {}public X509Certificate[] getAcceptedIssuers() {return null;}};private static X509TrustManager[] xtmArray = new X509TrustManager[] { xtm };private static HttpsURLConnection conn = null;public static String sendHttpsPost(String path, String params) throws Exception {// 组拼实体数据byte[] entity = params.getBytes("UTF-8");URL url = new URL(path);conn = (HttpsURLConnection) url.openConnection();if (conn instanceof HttpsURLConnection) {// Trust all certificatesSSLContext context = SSLContext.getInstance("TLS");context.init(new KeyManager[0], xtmArray, new SecureRandom());SSLSocketFactory socketFactory = context.getSocketFactory();((HttpsURLConnection) conn).setSSLSocketFactory(socketFactory);((HttpsURLConnection) conn).setHostnameVerifier(HOSTNAME_VERIFIER);}conn.setConnectTimeout(5 * 1000);conn.setReadTimeout(30000);conn.setDoInput(true);conn.setDoOutput(true);// 允许输出数据conn.setUseCaches(false);conn.setRequestMethod("POST");conn.setRequestProperty("Content-Type", "application/json");conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.6)");OutputStream outStream = new DataOutputStream(conn.getOutputStream());outStream.write(entity);outStream.flush();outStream.close();BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));StringBuffer sb = new StringBuffer();String line;while ((line = br.readLine()) != null) {sb.append(line);}return sb.toString();}public static void closeConnection() {if (conn != null)conn.disconnect();}
}