加密工具类 DESUtil

package com.xhrd.util;

import java.security.Key;
import java.security.Security;

import javax.crypto.Cipher;

import org.apache.commons.lang.StringUtils;

/**
 * 
 * 加密工具类
 * @author sigangjun
 *
 */
public class DESUtil {

/**
 * 加密方法
 * 
 * @param keyData密钥(用户名)
 * @param str要加密的字符串(密码)
 * @return
 * @throws Exception
 * @author sigangjun
 */
public static String encrypt(String keyData, String str) throws Exception {
if(StringUtils.isNotBlank(str)){
Security.addProvider(new com.sun.crypto.provider.SunJCE());
Key key = getKey(keyData.getBytes("utf-8"));
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, key);
return byteArr2HexStr(cipher.doFinal(str.getBytes("utf-8")));
}else{
return str;
}
}

/**
 * 解密方法
 * 
 * @param keyData密钥
 * @param str要解密的字符串
 * @return
 * @throws Exception
 * @author sigangjun
 */
public static String decrypt(String keyData, String str) throws Exception {
if (!StringUtils.isBlank(str)) {
Security.addProvider(new com.sun.crypto.provider.SunJCE());
Key key = getKey(keyData.getBytes("utf-8"));
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, key);
return new String(cipher.doFinal(hexStr2ByteArr(str)), "utf-8");
} else {
return str;
}
}

private static String byteArr2HexStr(byte[] arrB) throws Exception {
int iLen = arrB.length;
StringBuffer sb = new StringBuffer(iLen * 2);
for (int i = 0; i < iLen; i++) {
int intTmp = arrB[i];
while (intTmp < 0) {
intTmp = intTmp + 256;
}
if (intTmp < 16) {
sb.append(0);
}
sb.append(Integer.toString(intTmp, 16));
}
return sb.toString();
}

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

private static Key getKey(byte[] arrBTmp) throws Exception {
byte[] arrB = new byte[8];
for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
arrB[i] = arrBTmp[i];
}
Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");
return key;
}

public static void main(String[] args) {
String username = "[e-mail]";
String password = "sigangjun";
try {
 System.out.println("加密之前的字符串为：" + username);
 System.out.println("密钥为：" + password);
 String b = DESUtil.encrypt(username, password);
 System.out.println("加密之后的字符串为：" + b);
 System.out.println("加密之后的字符串长度为：" + b.length());
 password = DESUtil.decrypt(username, "0015f664ad6965a1de22b7a22b4ad76a");
 System.out.println("解密之后的字符串为：" + password);
} catch (Exception e) {
e.printStackTrace();
}
}

}