MD5加密

package com.library.app.instrument;

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

/**
 * 
 * @author admin
 * @see DesUtil
 */
public class MD5 {
    private static final char HEX_DIGITS[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

    /**
     * MD5
     * 
     * @param b
     *            byte数组
     * @return String byte数组处理后字符串
     */
    public static String toHexString(byte[] b) {// String to byte
        StringBuilder sb = new StringBuilder(b.length * 2);
        for (int i = 0; i < b.length; i++) {
            sb.append(HEX_DIGITS[(b[i] & 0xf0) >>> 4]);
            sb.append(HEX_DIGITS[b[i] & 0x0f]);
        }
        return sb.toString();

    }

    /**
     * MD5运算
     * 
     * @param s
     *            传入明文
     * @return String 返回密文
     */
    public static String md5(String s) {
        try {
            // Create MD5 Hash
            MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
            digest.update(s.getBytes());
            byte messageDigest[] = digest.digest();
            return toHexString(messageDigest);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return s;
    }
}