import java.security.Key;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

/**
 *
 * 使用DES加密與解密,可對(duì)byte[],String類型進(jìn)行加密與解密
 * 密文可使用String,byte[]存儲(chǔ).
 *
 * 方法:
 * void getKey(String strKey)從strKey的字條生成一個(gè)Key
 *
 * String getEncString(String strMing)對(duì)strMing進(jìn)行加密,返回String密文
 * String getDesString(String strMi)對(duì)strMin進(jìn)行解密,返回String明文
 *
 *byte[] getEncCode(byte[] byteS)byte[]型的加密
 *byte[] getDesCode(byte[] byteD)byte[]型的解密
 */

public class DesEncrypt {
  Key key;

  /**
   * 根據(jù)參數(shù)生成KEY
   * @param strKey
   */
   public void getKey(String strKey) {
    try {
      KeyGenerator _generator = KeyGenerator.getInstance("DES");
      _generator.init(new SecureRandom(strKey.getBytes()));
      this.key = _generator.generateKey();
      _generator = null;
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  /**
   * 加密String明文輸入,String密文輸出
   * @param strMing
   * @return
   */
  public String getEncString(String strMing) {
    byte[] byteMi = null;
    byte[] byteMing = null;
    String strMi = "";
    BASE64Encoder base64en = new BASE64Encoder();
    try {
      byteMing = strMing.getBytes("UTF8");
      byteMi = this.getEncCode(byteMing);
      strMi = base64en.encode(byteMi);
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      base64en = null;
      byteMing = null;
      byteMi = null;
    }
    return strMi;
  }

  /**
   * 解密 以String密文輸入,String明文輸出
   * @param strMi
   * @return
   */
  public String getDesString(String strMi) {
    BASE64Decoder base64De = new BASE64Decoder();
    byte[] byteMing = null;
    byte[] byteMi = null;
    String strMing = "";
    try {
      byteMi = base64De.decodeBuffer(strMi);
      byteMing = this.getDesCode(byteMi);
      strMing = new String(byteMing, "UTF8");
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      base64De = null;
      byteMing = null;
      byteMi = null;
    }
    return strMing;
  }

  /**
   * 加密以byte[]明文輸入,byte[]密文輸出
   * @param byteS
   * @return
   */
  private byte[] getEncCode(byte[] byteS) {
    byte[] byteFina = null;
    Cipher cipher;
    try {
      cipher = Cipher.getInstance("DES");
      cipher.init(Cipher.ENCRYPT_MODE, key);
      byteFina = cipher.doFinal(byteS);
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      cipher = null;
    }
    return byteFina;
  }

  /**
   * 解密以byte[]密文輸入,以byte[]明文輸出
   * @param byteD
   * @return
   */
  private byte[] getDesCode(byte[] byteD) {
    Cipher cipher;
    byte[] byteFina = null;
    try {
      cipher = Cipher.getInstance("DES");
      cipher.init(Cipher.DECRYPT_MODE, key);
      byteFina = cipher.doFinal(byteD);
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      cipher = null;
    }
    return byteFina;
  }

  public static void main(String args[]) {
    DesEncrypt des=new DesEncrypt();//實(shí)例化一個(gè)對(duì)像
    des.getKey("aadd");//生成密匙

    String strEnc = des.getEncString("明文");//加密字符串,返回String的密文
    System.out.println("加密文:"+strEnc);

    String strDes = des.getDesString(strEnc);//把String 類型的密文解密
    System.out.println("解密文:"+strDes);
  }
}