从cer证书中获取公钥

package com.tentcoo.bankAccount.util;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.security.PublicKey;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;

/**
 * 读取证书秘钥
 */
public class CerUtil {

    /**
     * 获取证书公钥
     * @param filePath 证书路径
     * @return
     */
    public static String getPublicKey(String filePath){
        String key="";
        try {
            CertificateFactory cf = CertificateFactory.getInstance("X.509");
            FileInputStream in = new FileInputStream(filePath);

            //生成一个证书对象并使用从输入流 inStream 中读取的数据对它进行初始化。
            Certificate c = cf.generateCertificate(in);
            PublicKey publicKey = c.getPublicKey();
            key = com.tentcoo.common.util.Base64.encode(publicKey.getEncoded());

        } catch (CertificateException e) {
            e.printStackTrace();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        return key;
    }
}