在web开发中，很多时候我们都需要操作cookie，比如登录可以基于cookie来实现，又或者使用cookie来存取我们某些数据

代码

    /**
     * 设置cookie有效期，根据需要自定义[本系统设置为30天]
     */
    private final static int COOKIE_MAX_AGE = 1000 * 60 * 60 * 24 * 30;

    /**
     *
     * @desc 删除指定Cookie
     * @param response
     * @param cookie
     */
    public static void removeCookie(HttpServletResponse response, 
                                    Cookie cookie) {
        if (cookie != null) {
            cookie.setPath("/");
            cookie.setValue("");
            cookie.setMaxAge(0);
            response.addCookie(cookie);
        }
    }

    /**
     *
     * @desc 删除指定Cookie
     * @param response
     * @param cookie
     * @param domain
     */
    public static void removeCookie(HttpServletResponse response, Cookie cookie,
                                    String domain) {
        if (cookie != null) {
            cookie.setPath("/");
            cookie.setValue("");
            cookie.setMaxAge(0);
            cookie.setDomain(domain);
            response.addCookie(cookie);
        }
    }

    /**
     *
     * @desc 根据Cookie名称得到Cookie的值，没有返回Null
     * @param request
     * @param name
     * @return
     */
    public static String getCookieValue(HttpServletRequest request, 
                                        String name) {
        Cookie cookie = getCookie(request, name);
        if (cookie != null) {
            return cookie.getValue();
        } else {
            return null;
        }
    }

    /**
     *
     * @desc 根据Cookie名称得到Cookie对象，不存在该对象则返回Null
     * @param request
     * @param name
     */
    public static Cookie getCookie(HttpServletRequest request, String name) {
        Cookie cookies[] = request.getCookies();
        if (cookies == null || name == null || name.length() == 0)
            return null;
        Cookie cookie = null;
        for (int i = 0; i < cookies.length; i++) {
            if (!cookies[i].getName().equals(name))
                continue;
            cookie = cookies[i];
            if (request.getServerName().equals(cookie.getDomain()))
                break;
        }

        return cookie;
    }

    /**
     *
     * @desc 添加一条新的Cookie信息，默认有效时间为一个月
     * @param response
     * @param name
     * @param value
     */
    public static void setCookie(HttpServletResponse response, String name, 
                                 String value) {
        setCookie(response, name, value, COOKIE_MAX_AGE);
    }

    /**
     *
     * @desc 添加一条新的Cookie信息，可以设置其最长有效时间(单位：秒)
     * @param response
     * @param name
     * @param value
     * @param maxAge
     */
    public static void setCookie(HttpServletResponse response, String name, 
                                 String value, int maxAge)
    {
            if (value == null)
                    value = "";
            Cookie cookie = new Cookie(name, value);
            if(maxAge!=0){
                cookie.setMaxAge(maxAge);
            }else{
                cookie.setMaxAge(COOKIE_MAX_AGE);
            }
            cookie.setPath("/");
            response.addCookie(cookie);
    }