package com.bw.yun.utils;

import java.security.MessageDigest;

import java.util.regex.Pattern;

public class StringUtils {

	/**

	 * 6>username<32 首字母为a-zA-Z

	 *

	 * @param username

	 * @return

	 */

	public static boolean checkUsername(String username) {

		return Pattern.matches("^[a-zA-Z]\\w{5,31}", username);

	}

	/**

	 * 密码判断 32>password>6

	 *

	 * @param password

	 * @return

	 */

	public static boolean checkPassword(String password) {

		return Pattern.matches("\\d{6.32}", password);

	}

	/**

	 * 密码使用MD5加密

	 *

	 * @param s

	 * @return

	 */

	public final static String MD5(String s) {

		char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

		try {

			byte[] strTemp = s.getBytes();

			MessageDigest mdTemp = MessageDigest.getInstance("MD5");

			mdTemp.update(strTemp);

			byte[] md = mdTemp.digest();

			int j = md.length;

			char str[] = new char[j * 2];

			int k = 0;

			for (int i = 0; i < j; i++) {

				byte b = md[i];

				str[k++] = hexDigits[b >> 4 & 0xf];

				str[k++] = hexDigits[b & 0xf];

			}

			return new String(str);

		} catch (Exception e) {

			return null;

		}

	}

}