Java生成非对称型加密公钥和私钥的方法

import java.io.*;import java.security.*;import javax.crypto.*;import javax.crypto.spec.*;/** * RSA非对称型加密的公钥和私钥 */public class KeyRSA { private KeyPairGenerator kpg = null; private KeyPair kp = null; private PublicKey public_key = null; private PrivateKey private_key = null; private FileOutputStream public_file_out = null; private ObjectOutputStream public_object_out = null; private FileOutputStream private_file_out = null; private ObjectOutputStream private_object_out = null; /**  * 构造函数  * @param in 指定密匙长度（取值范围：512～2048）  * @throws NoSuchAlgorithmException 异常  */ public KeyRSA(int in, String address) throws NoSuchAlgorithmException,   FileNotFoundException, IOException {  kpg = KeyPairGenerator.getInstance("RSA"); //创建‘密匙对'生成器  kpg.initialize(in); //指定密匙长度（取值范围：512～2048）  kp = kpg.genKeyPair(); //生成‘密匙对'，其中包含着一个公匙和一个私匙的信息  public_key = kp.getPublic(); //获得公匙  private_key = kp.getPrivate(); //获得私匙  //保存公匙  public_file_out = new FileOutputStream(address + "/public_key.dat");  public_object_out = new ObjectOutputStream(public_file_out);  public_object_out.writeObject(public_key);  //保存私匙  private_file_out = new FileOutputStream(address + "/private_key.dat");  private_object_out = new ObjectOutputStream(private_file_out);  private_object_out.writeObject(private_key); } public static void main(String[] args) {  try {   new KeyRSA(1024, "c:/key_rsa");  }  catch (IOException ex) {  }  catch (NoSuchAlgorithmException ex) {  } }}