java keystore导出证书，导出私钥，导出公钥

 

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;

/**
 * 导出证书(base64)，导出私钥，导出公钥
 * @author happyqing
 */
public class ExportCert {
	
	//导出证书 base64格式
	public static void exportCert(KeyStore keystore, String alias, String exportFile) throws Exception {
		Certificate cert = keystore.getCertificate(alias);
		BASE64Encoder encoder = new BASE64Encoder();
		String encoded = encoder.encode(cert.getEncoded());
		FileWriter fw = new FileWriter(exportFile);
		fw.write("-----BEGIN CERTIFICATE-----\r\n");	//非必须
		fw.write(encoded);
		fw.write("\r\n-----END CERTIFICATE-----");	//非必须
		fw.close();
	}

	//得到KeyPair
	public static KeyPair getKeyPair(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;
	}

	//导出私钥
	public static void exportPrivateKey(PrivateKey privateKey,String exportFile) throws Exception {
		BASE64Encoder encoder = new BASE64Encoder();
		String encoded = encoder.encode(privateKey.getEncoded());
		FileWriter fw = new FileWriter(exportFile);
		fw.write("—–BEGIN PRIVATE KEY—–\r\n");	//非必须
		fw.write(encoded);
		fw.write("\r\n—–END PRIVATE KEY—–");		//非必须
		fw.close();
	}
	
	//导出公钥
	public static void exportPublicKey(PublicKey publicKey,String exportFile) throws Exception {
		BASE64Encoder encoder = new BASE64Encoder();
		String encoded = encoder.encode(publicKey.getEncoded());
		FileWriter fw = new FileWriter(exportFile);
		fw.write("—–BEGIN PUBLIC KEY—–\r\n");		//非必须
		fw.write(encoded);
		fw.write("\r\n—–END PUBLIC KEY—–");		//非必须
		fw.close();
	}

	public static void main(String args[]) throws Exception {
		
		String keyStoreType = "JKS";
		//String keystoreFile = "C:/mykeystore";
		String keystoreFile = "C:/Documents and Settings/zhao/.keystore";
		String password = "123456";
		
		KeyStore keystore = KeyStore.getInstance(keyStoreType);
		keystore.load(new FileInputStream(new File(keystoreFile)), password.toCharArray());
		
		String alias = "cms";
		String exportCertFile = "C:/Documents and Settings/zhao/cms.cer";	
		String exportPrivateFile = "C:/Documents and Settings/zhao/cmsPrivateKey.txt";
		String exportPublicFile = "C:/Documents and Settings/zhao/cmsPublicKey.txt";
		
		ExportCert.exportCert(keystore, alias, exportCertFile);
		KeyPair keyPair = ExportCert.getKeyPair(keystore, alias, password.toCharArray());
		ExportCert.exportPrivateKey(keyPair.getPrivate(), exportPrivateFile);
		ExportCert.exportPublicKey(keyPair.getPublic(), exportPublicFile);
		
		System.out.println("OK");
	}
}