package org.test;

import java.net.URL;
import java.security.MessageDigest;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import javax.net.ssl.HttpsURLConnection;

public class Application {
    public static void main(String[] args) throws Exception {
 
       URL url = new URL("https://www.sina.com.cn");
    HttpsURLConnection conn = (HttpsURLConnection)url.openConnection();
    conn.connect();
    Certificate[] certs = conn.getServerCertificates();    //會拿到完整的證書鏈
    X509Certificate cert = (X509Certificate)certs[0];    //cert[0]是證書鏈的最下層
	System.out.println("序號：" + cert.getSerialNumber());
 
	System.out.println("頒發給：" + cert.getSubjectDN().getName());
	System.out.println("頒發者：" + cert.getIssuerDN().getName());
	System.out.println("起始：" + cert.getNotBefore());
	System.out.println("過期：" + cert.getNotAfter());
	System.out.println("算法：" + cert.getSigAlgName());
 
	System.out.println("指紋：" + getThumbPrint(cert));
	
	conn.disconnect();
    }

    private static String getThumbPrint(X509Certificate cert) throws Exception {
        MessageDigest md = MessageDigest.getInstance("SHA-1");
        byte[] der = cert.getEncoded();
        md.update(der);
        byte[] digest = md.digest();

        return bytesToHexString(digest);
    }
    
    private static String bytesToHexString(byte[] src) {
        StringBuilder stringBuilder = new StringBuilder("");
        if (src == null || src.length <= 0) {
            return null;
        }
        for (int i = 0; i < src.length; i++) {
            int v = src[i] & 0xFF;
            String hv = Integer.toHexString(v);
            if (hv.length() < 2) {
                stringBuilder.append(0);
            }
            stringBuilder.append(hv);
        }

        return stringBuilder.toString();
    }
}

運行看效果，得到的輸出：

與之前是一樣的。

獲取服務端https證書 - Java版