读取Cert格式证书的密钥

不想存储Cert证书内容，只想存储证书密钥，可通过以下2種方式实现

一、通過java读取证书的密钥出来： 

package com.zat.ucop.service.util;

import sun.misc.BASE64Encoder;

import java.io.FileInputStream;
import java.security.PublicKey;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

/**
 * 读取cert格式证书的密钥.
 *
 * @author weixiong.cao
 * @date 2019/4/3
 */
public class ReadCerDemo {
    public static void main(String[] args) throws Exception {
        String keyStorePath = "E:/mpay公钥/client_02.cer";

        CertificateFactory cf = CertificateFactory.getInstance("X.509");
        X509Certificate cert = (X509Certificate) cf.generateCertificate(new FileInputStream(keyStorePath));
        PublicKey publicKey = cert.getPublicKey();
        BASE64Encoder base64Encoder = new BASE64Encoder();
        String publicKeyString = base64Encoder.encode(publicKey.getEncoded());
        System.out.println("-----------------公钥--------------------");
        System.out.println(publicKeyString);
        System.out.println("-----------------公钥--------------------");
    }
}

二、通過openssl命令讀取

進入linux控制臺，輸入以下命令：

openssl x509 -in ./client_02.cer -pubkey -noout > ./mpayPubKey.pubkey

以上命令會將證書內容生成到一個 mpayPubKey.pubkey 文件，文件內容如下：