package com.common.util;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import java.security.Key;
import java.security.SecureRandom;

public class DESUtil {
    Key key ;
    public DESUtil() {

    }
    public DESUtil(String str) {
        setKey(str); // 生成密匙
    }
    public Key getKey() {
        return key ;
    }
    public void setKey(Key key) {
        this . key = key;
    }
    public void setKey(String strKey) {
        try {
            KeyGenerator _generator = KeyGenerator.getInstance ( "DES" );
            _generator.init( new SecureRandom(strKey.getBytes("utf-8")));
            SecureRandom secureRandom= SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(strKey.getBytes());
            _generator.init(56, secureRandom);
            this.key = _generator.generateKey();
            _generator = null ;
        } catch (Exception e) {
            throw new RuntimeException("Error initializing class. Cause: " + e);
        }
    }

    /**
     * 加密 String 明文輸入 ,String 密文輸出
     */
    public String encryptStr(String strMing) {
        byte [] byteMi = null ;
        byte [] byteMing = null ;
        String strMi = "" ;
        BASE64Encoder base64en = new BASE64Encoder();
        try {
            byteMing = strMing.getBytes( "UTF-8" );
            byteMi = this.encryptByte(byteMing);
            strMi = base64en.encode(byteMi);
        } catch (Exception e) {
            throw new RuntimeException("Error initializing class. Cause: " + e);
        } 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 decryptStr(String strMi) {
        BASE64Decoder base64De = new BASE64Decoder();
        byte [] byteMing = null ;
        byte [] byteMi = null ;
        String strMing = "" ;
        try {
            byteMi = base64De.decodeBuffer(strMi);
            byteMing = this.decryptByte(byteMi);
            strMing = new String(byteMing, "UTF-8" );
        } catch (Exception e) {
            throw new RuntimeException("Error initializing class. Cause: " + e);
        } 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 [] encryptByte( 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) {
            throw new RuntimeException("Error initializing class. Cause: " + e);
        } finally {
            cipher = null ;
        }
        return byteFina;
    }

    /**
     * 解密以 byte[] 密文輸入 , 以 byte[] 明文輸出
     *
     * @param byteD
     * @return
     */
    private byte [] decryptByte( 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) {
            throw new RuntimeException("Error initializing class. Cause: " + e);
        } finally {
            cipher = null ;
        }
        return byteFina;
    }
    public static void main(String[] args) throws Exception {
        DESUtil des = new DESUtil("jrkj123");
        String str1 = "4cdbc040657a4847b2667e31d9e2c3d9" ;
        // DES 加密字串
        String str2 = des.encryptStr(str1);
        // DES 解密字串
        String deStr = des.decryptStr(str2);
        System. out .println( " 加密前： " + str1);
        System. out .println( " 加密後： " + str2);
        System. out .println( " 解密後： " + deStr);
    }
}