java MD5加密

package com.wcg.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/*
 * MD5 算法
 */
public class MD5 {

	// 全局数组
	private final static String[] strDigits = { "0", "1", "2", "3", "4", "5",
			"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

	public MD5() {
	}

	// 返回形式为数字跟字符串
	private static String byteToArrayString(byte bByte) {
		int iRet = bByte;
		// System.out.println("iRet="+iRet);
		if (iRet < 0) {
			iRet += 256;
		}
		int iD1 = iRet / 16;
		int iD2 = iRet % 16;
		return strDigits[iD1] + strDigits[iD2];
	}

	// 返回形式只为数字
	private static String byteToNum(byte bByte) {
		int iRet = bByte;
		System.out.println("iRet1=" + iRet);
		if (iRet < 0) {
			iRet += 256;
		}
		return String.valueOf(iRet);
	}

	// 转换字节数组为16进制字串
	private static String byteToString(byte[] bByte) {
		StringBuffer sBuffer = new StringBuffer();
		for (int i = 0; i < bByte.length; i++) {
			sBuffer.append(byteToArrayString(bByte[i]));
		}
		return sBuffer.toString();
	}

	public static String GetMD5Code(String strObj) {
		String resultString = null;
		try {
			resultString = new String(strObj);
			MessageDigest md = MessageDigest.getInstance("MD5");
			// md.digest() 该函数返回值为存放哈希值结果的byte数组
			resultString = byteToString(md.digest(strObj.getBytes()));
		} catch (NoSuchAlgorithmException ex) {
			ex.printStackTrace();
		}
		return resultString;
	}

	public static String test(String str) {
		StringBuilder sb = new StringBuilder();
		try {
			byte[] buf = str.getBytes();
			MessageDigest md5 = MessageDigest.getInstance("MD5");
			md5.update(buf);
			byte[] tmp = md5.digest();
			for (byte b : tmp) {
				sb.append(Integer.toHexString(b & 0xff));
			}
		} catch (NoSuchAlgorithmException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return sb.toString();
	}

	public static void main(String[] args) {
//		MD5 getMD5 = new MD5();
		System.out.println(MD5.GetMD5Code("abcd123"));
	}
}