从Java Keystore文件中提取私钥、证书

转：http://blog.csdn.net/moreorless/article/details/4985940

Keystore是一个密码保护的文件，存放私钥和证书。可以通过JDK自带的keytool工具生成。

但是keytool工具，并没有提供方便的方法，从keystore文件中到处私钥和证书。

所以可以通过JDK提供的java.security.KeyStore 类来编码完成相关工作。

参见：

http://www.anandsekar.com/2006/01/19/exporting-the-private-key-from-a-jks-keystore/

 

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileWriter;
 import java.security.Key;
 import java.security.KeyPair;
 import java.security.KeyStore;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
 import java.security.PrivateKey;
 import java.security.PublicKey;
 import java.security.UnrecoverableKeyException;
 import java.security.cert.Certificate;


 import sun.misc.BASE64Encoder;

 public class ExportPrivateKey {
         private File keystoreFile;
         private String keyStoreType;
         private char[] password;
         private String alias;
         private File exportedFile;

         public static KeyPair getPrivateKey(KeyStore keystore, String alias, char[] password) {
                 try {
                         Key key=keystore.getKey(alias,password);
                         if(key instanceof PrivateKey) {
                                 Certificate cert=keystore.getCertificate(alias);
                                 PublicKey publicKey=cert.getPublicKey();
                                 return new KeyPair(publicKey,(PrivateKey)key);
                         }
                 } catch (UnrecoverableKeyException e) {
         } catch (NoSuchAlgorithmException e) {
         } catch (KeyStoreException e) {
         }
         return null;
         }



         public void export() throws Exception{
                 KeyStore keystore=KeyStore.getInstance(keyStoreType);
                 BASE64Encoder encoder=new BASE64Encoder();
                 keystore.load(new FileInputStream(keystoreFile),password);
                 KeyPair keyPair=getPrivateKey(keystore,alias,password);
                 PrivateKey privateKey=keyPair.getPrivate();
                 String encoded=encoder.encode(privateKey.getEncoded());
                 FileWriter fw=new FileWriter(exportedFile);
                 fw.write(“—–BEGIN PRIVATE KEY—–/n“);
                 fw.write(encoded);
                 fw.write(“/n“);
                 fw.write(“—–END PRIVATE KEY—–”);
                 fw.close();

         }


         public static void main(String args[]) throws Exception{
                 ExportPrivateKey export=new ExportPrivateKey();
                 export.keystoreFile=new File(args[0]);
                 export.keyStoreType=args[1];
                 export.password=args[2].toCharArray();
                 export.alias=args[3];
                 export.exportedFile=new File(args[4]);
                 export.export();
         }
 }