DES加密算法

package com.example.zzti;

import java.security.*;
import javax.crypto.*;

public class DESPlus {

    public static String encrypt(String strKey, String strIn) throws Exception {
        Security.addProvider(new com.sun.crypto.provider.SunJCE());
        Key key = getKey(strKey);
       
        Cipher encryptCipher = Cipher.getInstance("DES");
        encryptCipher.init(Cipher.ENCRYPT_MODE, key);

        return byteArr2HexStr(encryptCipher.doFinal((strIn.getBytes())));
    }
   
    public static String decrypt(String strKey, String strIn) throws Exception {
        Security.addProvider(new com.sun.crypto.provider.SunJCE());
        Key key = getKey(strKey);

        Cipher decryptCipher = Cipher.getInstance("DES");
        decryptCipher.init(Cipher.DECRYPT_MODE, key);
        return new String(decryptCipher.doFinal((hexStr2ByteArr(strIn))));
    }
   
    private static Key getKey(String strKey) throws Exception {
       
        byte[] arrBTmp = strKey.getBytes();    //获取字节流
        byte[] arrB = new byte[8];             //创建一个空的8位字节数组（默认值为0）

        //将原始字节数组转换为8位
        for(int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
            arrB[i] = arrBTmp[i];
        }

        // 生成密钥
        Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");

        return key;
    }
   
    private static String byteArr2HexStr(byte[] arrB) throws Exception {
        int iLen = arrB.length;
        // 每个byte用两个字符才能表示，所以字符串的长度是数组长度的两倍
        StringBuffer sb = new StringBuffer(iLen * 2);
        for (int i = 0; i < iLen; i++) {
            int intTmp = arrB[i];
            // 把负数转换为正数
            while (intTmp < 0) {
                intTmp = intTmp + 256;
            }
            // 小于0F的数需要在前面补0
            if (intTmp < 16) {
                sb.append("0");
            }
            sb.append(Integer.toString(intTmp, 16));
        }
        return sb.toString();
    }

    private static byte[] hexStr2ByteArr(String strIn) throws Exception {
        byte[] arrB = strIn.getBytes();
        int iLen = arrB.length;

        // 两个字符表示一个字节，所以字节数组长度是字符串长度除以2
        byte[] arrOut = new byte[iLen / 2];
        for (int i = 0; i < iLen; i = i + 2) {
            String strTmp = new String(arrB, i, 2);
            arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
        }
        return arrOut;
    }
   
    public static void main(String[] args) {
        try {       
            String Code = "des加密测试";
            String key = "12345678";
            String codE;
           
            codE = DESPlus.encrypt(key, Code);
           
            System.out.println("加密前的字串：" + Code);
            System.out.println("加密所用密钥：" + key);
            System.out.println("加密后的字串：" + codE);
            System.out.println("解密后的字串：" + DESPlus.decrypt(key, codE));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}