import java.security.KeyPair;  import java.security.KeyPairGenerator;  import java.security.interfaces.RSAPrivateKey;  import java.security.interfaces.RSAPublicKey;  import javax.crypto.Cipher;    /**   * RSA加密类   *    */  public class RSAEncrypt {     public static void main(String[] args) {    try {     RSAEncrypt encrypt = new RSAEncrypt();     String encryptText = "12345678";     KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");     keyPairGen.initialize(1024);     KeyPair keyPair = keyPairGen.generateKeyPair();     // Generate keys     RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); // 私钥     RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 公钥     byte[] e = encrypt.encrypt(publicKey, encryptText.getBytes());     byte[] de = encrypt.decrypt(privateKey, e);     System.out.println(encrypt.bytesToString(e));     System.out.println();       System.out.println(encrypt.bytesToString(de));    } catch (Exception e) {     e.printStackTrace();    }   }     /**    * byte数组转为string    *     * @param encrytpByte    * @return    */   protected String bytesToString(byte[] encrytpByte) {    String result = "";    for (Byte bytes : encrytpByte) {     result += (char) bytes.intValue();    }    return result;   }     /**    * 加密方法    *     * @param publicKey    * @param obj    * @return    */   protected byte[] encrypt(RSAPublicKey publicKey, byte[] obj) {    if (publicKey != null) {     try {      Cipher cipher = Cipher.getInstance("RSA");      cipher.init(Cipher.ENCRYPT_MODE, publicKey);      return cipher.doFinal(obj);     } catch (Exception e) {      e.printStackTrace();     }    }    return null;   }     /**    * 解密方法    *     * @param privateKey    * @param obj    * @return    */   protected byte[] decrypt(RSAPrivateKey privateKey, byte[] obj) {    if (privateKey != null) {     try {      Cipher cipher = Cipher.getInstance("RSA");      cipher.init(Cipher.DECRYPT_MODE, privateKey);      return cipher.doFinal(obj);     } catch (Exception e) {      e.printStackTrace();     }    }    return null;   }  }