今天完成的任务

学习了先贤对cookie的操作

昨天已经回如何生成一个cookie

现在学获取

public static Cookie    getCookie(HttpServletRequest request, String cookieName) {
    Cookie[] cookies = request.getCookies();

    if (cookies == null || cookieName == null || cookieName.equals(""))
        return null;

    for (Cookie c : cookies) {
        if (c.getName().equals(cookieName))//输出与cookieName相符合的Cookie值
            return (Cookie) c;
    }
    return null;
}


public static String getCookieValue(HttpServletRequest request, String cookieName) {
    Cookie cookie = getCookie(request, cookieName);
    if (cookie == null)
        return null;
    else
        return cookie.getValue();
}

request返回的是cookie的集合 通过getCookies（）获得

c.getName().equals(cookieName判断需要查询的cookie名称

cookie.getValue()获取cookie的内容

虽然单纯用这几个语句也能做到一样的效果，不过先贤的判断语句还是让人学到很多

方法里面居然能调用它的重载，学到了

-----------------------------------------------------------

public static void addCookie(HttpServletResponse response, Cookie cookie) {
    if (cookie != null)
        response.addCookie(cookie);
}


public static void addCookie(HttpServletResponse response, String cookieName, String cookieValue, String domain,
                             boolean httpOnly, int maxAge, String path, boolean secure) {
    if (cookieName != null && !cookieName.equals("")) {
        if (cookieValue == null)
            cookieValue = "";

        Cookie newCookie = new Cookie(cookieName, cookieValue);
        if (domain != null)
            newCookie.setDomain(domain);

        newCookie.setHttpOnly(httpOnly);

        if (maxAge > 0)
            newCookie.setMaxAge(maxAge);

        if (path == null)
            newCookie.setPath("/");
        else
            newCookie.setPath(path);

        newCookie.setSecure(secure);

        addCookie(response, newCookie);
    }
}


public static void addCookie(HttpServletResponse response, String cookieName, String cookieValue, String domain) {
    addCookie(response, cookieName, cookieValue, domain, true, CookieConstantTable.COOKIE_MAX_AGE, "/", false);
}

添加语句

---------------------------------

修改语句

其实cookie只支持创建和读取，修改和删除都是基于cookie方法的小把戏

public static void editCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
                              String cookieValue,String domain) {
    Cookie c = getCookie(request, cookieName);
    if (c != null && cookieName != null && !cookieName.equals("") && c.getName().equals(cookieName)) {
        addCookie(response, cookieName, cookieValue, domain);
    }
}

修改是把查询到的语句通过addCookie方法覆盖

---------------------------------------------------------------------------------------------------------------------------

删除

public static void delCookie(HttpServletResponse response, Cookie cookie) {
    if (cookie != null) {
        cookie.setPath("/");
        cookie.setMaxAge(0);
        cookie.setValue(null);

        response.addCookie(cookie);
    }
}


public static void delCookie(HttpServletRequest request, HttpServletResponse response, String cookieName) {
    Cookie c = getCookie(request, cookieName);
    if (c != null && c.getName().equals(cookieName)) {
        delCookie(response, c);
    }
}

实际上就是修改path 生命周期 value三条命令 消除cookie的