无法删除Cookie（Java Web）

Question

我在删除Cookie时遇到问题

MemberArea.jsp

<%
Cookie[] cookies = request.getCookies();
if(cookies != null)
{
    for(Cookie cookie: cookies)
    {
        if(cookie.getName().equals("username"))
            username = cookie.getValue();
        else if(cookie.getName().equals("JSESSIONID"))
            sessionID = cookie.getValue();          
    }
}
if(username == null || sessionID == null)
    response.sendRedirect("login.jsp");
%>
Username: <%=username %> <br>
Current Session: <%=sessionID %>

<form action="<%= request.getContextPath() %>/MemberAreaController" 
 method="get">
    <input type="hidden" name="action" value="destroy">
    <input type="Submit" value="Logout">
</form>
</body>

下面的代码（MemberController.java）是从MemberArea.jsp触发的

request.getSession().invalidate();
Cookie[] cookies = request.getCookies();
System.out.println(cookies);
for(Cookie cookie: cookies)
{       
    System.out.println(cookie.getName());
    System.out.println(cookie.getValue());
    cookie.setValue(null);
    cookie.setMaxAge(0);
    cookie.setPath("/");
    response.addCookie(cookie);
} 
response.sendRedirect("login.jsp");

单击注销按钮并返回MemberArea.jsp后，用户仍将登录。