java cookie

public static void delCookie(HttpServletRequest request,HttpServletResponse response,String name) {
        Cookie cookie = getCookieByName(request, name);
        if(cookie != null) {
            cookie.setMaxAge(0);
            cookie.setPath("/");
            response.addCookie(cookie);
        }
    }
    
    /**
     * set cookie
     * @param response
     * @param name
     * @param value
     * @param maxAge
     */
    public static void addCookie(HttpServletResponse response,String name,String value,int maxAge){
        Cookie cookie = new Cookie(name,value);
        cookie.setPath("/");
        if(maxAge>0)  cookie.setMaxAge(maxAge);
        response.addCookie(cookie);
    }
    
    public static Cookie getCookieByName(HttpServletRequest request,String name){
        Map<String,Cookie> cookieMap = ReadCookieMap(request);
        if(cookieMap.containsKey(name)){
            Cookie cookie = (Cookie)cookieMap.get(name);
            return cookie;
        }else{
            return null;
        }   
    }
     
    private static Map<String,Cookie> ReadCookieMap(HttpServletRequest request){  
        Map<String,Cookie> cookieMap = new HashMap<String,Cookie>();
        Cookie[] cookies = request.getCookies();
        if(null!=cookies){
            for(Cookie cookie : cookies){
                cookieMap.put(cookie.getName(), cookie);
            }
        }
        return cookieMap;
    }