Java从证书库文件中导出RSA公钥私钥

RSA的证书的生成，见博文：http://blog.csdn.net/yx0628/article/details/78421017

下面是Java从证书库keystore文件，及证书cer文件中提取私钥，公钥的示例代码：

import java.io.FileInputStream;import java.security.KeyStore;import java.security.PrivateKey;import java.security.PublicKey;import java.security.cert.CertificateFactory;import java.security.cert.X509Certificate;import sun.misc.BASE64Encoder;public class Demo {public static void main(String[] args) throws Exception {String cerPath = "D:/mypublickey.cer";//证书文件路径String storePath = "D:/mykeystore.keystore";//证书库文件路径String alias = "mykey";//证书别名String storePw = "123456";//证书库密码String keyPw = "123456";//证书密码System.out.println("从证书获取的公钥为:" + getPublicKey(cerPath));System.out.println("从证书获取的私钥为:" + getPrivateKey(storePath, alias, storePw, keyPw));}private static String getPublicKey(String cerPath) throws Exception {CertificateFactory certificatefactory = CertificateFactory.getInstance("X.509");FileInputStream fis = new FileInputStream(cerPath);X509Certificate Cert = (X509Certificate) certificatefactory.generateCertificate(fis);PublicKey pk = Cert.getPublicKey();String publicKey = new BASE64Encoder().encode(pk.getEncoded());return publicKey;}private static String getPrivateKey(String storePath, String alias, String storePw, String keyPw) throws Exception {FileInputStream is = new FileInputStream(storePath);KeyStore ks = KeyStore.getInstance("JKS");ks.load(is, storePw.toCharArray());is.close();PrivateKey key = (PrivateKey) ks.getKey(alias, keyPw.toCharArray());System.out.println("privateKey:" + new BASE64Encoder().encode(key.getEncoded()));String privateKey = new BASE64Encoder().encode(key.getEncoded());return privateKey;}}

运行结果：可以看到公钥和私钥，私钥自己保存好即可。