des 加密解密

package com.channelsoft.cellphone.background.login.util;

import java.security.*;

import javax.crypto.KeyGenerator;
import javax.crypto.Cipher;

/**
* 使用DES加密与解密,可对byte[],String类型进行加密与解密 密文可使用String,byte[]存储
* @author lenovo
*
*/
public class DesUtil {
private static Key key;

public static void getKey(String strKey) {
try {
KeyGenerator _generator = KeyGenerator.getInstance("DES");
_generator.init(new SecureRandom(strKey.getBytes()));
key = _generator.generateKey();
_generator = null;
} catch (Exception e) {
e.printStackTrace();
}
}
//加密String明文输入,String密文输出
public static String getEncString(String strMing) {
byte[] byteMi = null;
byte[] byteMing = null;
String strMi = "";
try {
return byte2hex(getEncCode(strMing.getBytes()));
// byteMing = strMing.getBytes("UTF8");
// byteMi = this.getEncCode(byteMing);
// strMi = new String( byteMi,"UTF8");
} catch (Exception e) {
e.printStackTrace();
} finally {
byteMing = null;
byteMi = null;
}
return null;
}

//解密 以String密文输入,String明文输出
public static String getDesString(String strMi) {
byte[] byteMing = null;
byte[] byteMi = null;
String strMing = "";
try {
return new String(getDesCode(hex2byte(strMi.getBytes())));
// byteMing = this.getDesCode(byteMi);
// strMing = new String(byteMing,"UTF8");
} catch (Exception e) {
e.printStackTrace();
} finally {
byteMing = null;
byteMi = null;
}
return strMing;

}

//加密以byte[]明文输入,byte[]密文输出
private static 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[]密文输入,以byte[]明文输出
private static 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;
}

//二行制转字符串
public static String byte2hex(byte[] b) { // 一个字节的数，
// 转成16进制字符串
String hs = "";
String stmp = "";
for (int n = 0; n < b.length; n++) {
// 整数转成十六进制表示
stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
if (stmp.length() == 1)
hs = hs + "0" + stmp;
else
hs = hs + stmp;
}
return hs.toUpperCase(); // 转成大写
}

public static byte[] hex2byte(byte[] b) {
if ((b.length % 2) != 0)
throw new IllegalArgumentException("长度不是偶数");
byte[] b2 = new byte[b.length / 2];
for (int n = 0; n < b.length; n += 2) {
String item = new String(b, n, 2);
// 两位一组，表示一个字节,把这样表示的16进制字符串，还原成一个进制字节
b2[n / 2] = (byte) Integer.parseInt(item, 16);
}
return b2;
}


/**
* DES加密解密算法
* @param args
* @CreateDate:2012-8-7
* @author yangliulv
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
// DesUtil des = new DesUtil(); //实例化一个对像
// des.getKey("aadd"); //生成密匙
//
// String strEnc = des.getEncString("明文122"); //加密字符串,返回String的密文
// System.out.println(strEnc+":加密后长度为"+strEnc.length());
//
// //解密
// String strDes = des.getDesString(strEnc); //把String 类型的密文解密
// System.out.println(strDes);
String key = ResourceConfig.getDesKey();
DesUtil.getKey(key); //生成密匙

String strEnc = DesUtil.getEncString("明文122"); //加密字符串,返回String的密文
System.out.println(strEnc+":加密后长度为"+strEnc.length());

//解密
String strDes = DesUtil.getDesString(strEnc); //把String 类型的密文解密
System.out.println(strDes);
}

}