Cookie中存放数据l加密解密的算法

public class CookieUtil {
 
	 
	/**
	 * 
	 * @param response HttpServletResponse类型的响应
	 * @param cookie 要设置httpOnly的cookie对象
	 */
	public static void addHttpOnlyCookie(HttpServletResponse response,
			Cookie cookie) {
		// 判断对象是否存在null的情况
		if (checkObjIsNull(response) || checkObjIsNull(cookie)) {
			return;
		}

		//依次取得cookie中的名称、值、最大生存时间、路径、域和是否为安全协议信息
		String cookieName = cookie.getName();
		String cookieValue = cookie.getValue();
		int maxAge = cookie.getMaxAge();
		String path = cookie.getPath();
		String domain = cookie.getDomain();
		boolean isSecure = cookie.getSecure();

		StringBuffer strBufferCookie = new StringBuffer();
		strBufferCookie.append(cookieName + "=" + cookieValue + ";");

		if (maxAge >= 0) {
			strBufferCookie.append("Max-Age=" + maxAge + ";");
		} else {
			strBufferCookie.append("Max-Age=25;");
		}

		if (!checkObjIsNull(domain)) {
			strBufferCookie.append("domain=" + domain + ";");
		}

		if (!checkObjIsNull(path)) {
			strBufferCookie.append("path=" + path + ";");
		}

		if (isSecure) {
			strBufferCookie.append("HttpOnly;Secure;");
		} else {
			strBufferCookie.append("HttpOnly;");
		}

		response.addHeader("Set-Cookie", strBufferCookie.toString());
	}

	private static boolean checkObjIsNull(Object obj) {
		if (obj == null) {
			return true;
		}
		return false;
	}
	
	/**
	 * cookie中的值加密
	 */
	public static String encodeCookie(String value){
		String encode = "";
		byte bytes[];
		try {
			bytes = value.getBytes("utf-8");
			encode = encode_base64(bytes,bytes.length);	
		} catch (UnsupportedEncodingException e) {			
			e.printStackTrace();
		}
		return encode;
	}
	/**
	 * cookie中值解密
	 */
	public static String decodeCookie(String value){
		byte bytes[];							
		String decode = "";
		try {
			bytes = decode_base64(value,10);
			decode = new String(bytes,"UTF-8");
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
		return decode;
	}
	
	static private final char base64_code[] = {
		'.', '/', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
		'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V',
		'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
		'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
		'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5',
		'6', '7', '8', '9'
	};

	// Table for Base64 decoding
	static private final byte index_64[] = {
		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
		-1, -1, -1, -1, -1, -1, 0, 1, 54, 55,
		56, 57, 58, 59, 60, 61, 62, 63, -1, -1,
		-1, -1, -1, -1, -1, 2, 3, 4, 5, 6,
		7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
		17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
		-1, -1, -1, -1, -1, -1, 28, 29, 30,
		31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
		41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
		51, 52, 53, -1, -1, -1, -1, -1
	};
	private static String encode_base64(byte d[], int len)	throws IllegalArgumentException {
		int off = 0;
		StringBuffer rs = new StringBuffer();
		int c1, c2;
	
		if (len <= 0 || len > d.length)
			throw new IllegalArgumentException ("Invalid len");
	
		while (off < len) {
			c1 = d[off++] & 0xff;
			rs.append(base64_code[(c1 >> 2) & 0x3f]);
			c1 = (c1 & 0x03) << 4;
			if (off >= len) {
				rs.append(base64_code[c1 & 0x3f]);
				break;
			}
			c2 = d[off++] & 0xff;
			c1 |= (c2 >> 4) & 0x0f;
			rs.append(base64_code[c1 & 0x3f]);
			c1 = (c2 & 0x0f) << 2;
			if (off >= len) {
				rs.append(base64_code[c1 & 0x3f]);
				break;
			}
			c2 = d[off++] & 0xff;
			c1 |= (c2 >> 6) & 0x03;
			rs.append(base64_code[c1 & 0x3f]);
			rs.append(base64_code[c2 & 0x3f]);
		}
		return rs.toString();
	}
	private static byte char64(char x) {
		if ((int)x < 0 || (int)x > index_64.length)
			return -1;
		return index_64[(int)x];
	}
	private static byte[] decode_base64(String s, int maxolen) throws IllegalArgumentException {
		StringBuffer rs = new StringBuffer();
		int off = 0, slen = s.length(), olen = 0;
		byte ret[];
		byte c1, c2, c3, c4, o;
	
		if (maxolen <= 0)
			throw new IllegalArgumentException ("Invalid maxolen");	
		while (off < slen - 1 && olen < maxolen) {
			c1 = char64(s.charAt(off++));
			c2 = char64(s.charAt(off++));
			if (c1 == -1 || c2 == -1)
				break;
			o = (byte)(c1 << 2);
			o |= (c2 & 0x30) >> 4;
			rs.append((char)o);
			if (++olen >= maxolen || off >= slen)
				break;
			c3 = char64(s.charAt(off++));
			if (c3 == -1)
				break;
			o = (byte)((c2 & 0x0f) << 4);
			o |= (c3 & 0x3c) >> 2;
			rs.append((char)o);
			if (++olen >= maxolen || off >= slen)
				break;
			c4 = char64(s.charAt(off++));
			o = (byte)((c3 & 0x03) << 6);
			o |= c4;
			rs.append((char)o);
			++olen;
		}
	
		ret = new byte[olen];
		for (off = 0; off < olen; off++)
			ret[off] = (byte)rs.charAt(off);
		return ret;
	}
	
	public static void main(String[] args) {
		encodeCookie("admin");
//		[97, 100, 109, 105, 110]
//		[97, 100, 109, 105, 110]
		decodeCookie("WUPrYU2");
	}
}