8、使用浏览器Cookie

wavaya · 发表于 2013-1-26 14:03:20

使用浏览器Cookie

set-cookie:message=hello

注意：
Cookie就是一段文本。Cookie只能用于存储字符串值。

可以创建两种类型的cookie:会话Cookie和持久化Cookie
会话Cookie只存于内存，当用户关闭浏览器时，会话Cookie就永远消失了。
持久化Cookie可以存在几个月甚至几年。持久化Cookie创建后，会被浏览器长久地保存在用户的电脑上。
\Documents and Settings\[user]\Cookies

1、Cookie的安全性限制
首先，所有的Cookie是与域名相关的
其次，浏览器存储Cookie的重要限制是其大小的限制不能超过4096字节（包含所有的Cookie名称和值在内）
最后，大多数浏览器都限制可以被设置的cookie数量，一个域名不超过20个cookie （IE除外）

2、创建Cookie
Response.Cookies 集合添加Cookie
<%@ Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void btnAdd_Click(object sender, EventArgs e) {       Response.Cookies["message"].Value = txtCookieValue.Text; }</script><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div>       <asp:Label ID="lblCookieValue" runat="server" AssociatedControlID="txtCookieValue"          Text="Cookie Value"></asp:Label>       <asp:TextBox ID="txtCookieValue" runat="server"></asp:TextBox>       <asp:Button ID="btnAdd" runat="server" Text="Add Value"  /> </div> </form></body></html>
Cookie的名称是区分大小写的。
2011-5-11 11:48 danny

创建持久化的Cookie
<%@ Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void Page_Load(object sender, EventArgs e) {       int counter = 0;       if (Request.Cookies["counter"] != null)          counter = Int32.Parse(Request.Cookies["counter"].Value);       counter++;       Response.Cookies["counter"].Value = counter.ToString();       Response.Cookies["counter"].Expires = DateTime.Now.AddYears(2);       lblCounter.Text = counter.ToString(); }</script><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div>       You have visited this page       <asp:Label ID="lblCounter" runat="server" Text="Label"></asp:Label>       times! </div> </form></body></html>
Response.Cookies["counter"].Expires = DateTime.Now.AddYears(2);
设为两年。当为某个Cookie设置了过期时间后，该Cookie就被保存为持久化cookie了。

3、读取Cookie
可以使用Response.Cookies集合创建和修改Cookie，
可以使用Request.Cookies集合读取Cookie值

GetCookies.aspx
<%@ Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void Page_Load(object sender, EventArgs e) {       ArrayList colCookies = new ArrayList();       for (int i = 0; i < Request.Cookies.Count; i++)          colCookies.Add(Request.Cookies[i]);       grdCookies.DataSource = colCookies;       grdCookies.DataBind(); }</script><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div>       <asp:GridView ID="grdCookies" runat="server">       </asp:GridView> </div> </form></body></html>

4、设置Cookie属性
Domain 关联到的Cookie的域名。默认当前域名
Expires  指定过期时间
HasKeys  确定该Cookie是否是一个多值cookie
HttpOnly 避免Cookie被JavaScript访问
Name 用户指定Cookie的名称
Path 关联到Cookie的路径。默认值是/
Secure  指定Cookie需要通过SSL连接传递
Value 允许读/写Cookie的值
Values  多值

5、删除Cookie
删除Cookie的方法并不直观。要删除一个存在的Cookie，必须设置其过期时间为一个过去的时间。

DeleteAllCookies.aspx
<%@ Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void Page_Load(object sender, EventArgs e) {       string[]          cookies = Request.Cookies.AllKeys;       foreach (string cookie in cookies)       {          BulletedList1.Items.Add("Deleting " + cookie);          Response.Cookies[cookie].Expires = DateTime.Now.AddDays(-1);       } }</script><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div>       <asp:BulletedList ID="BulletedList1" EnableViewState="false" runat="server">       </asp:BulletedList> </div> </form></body></html>

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

protected void Page_Load(object sender, EventArgs e)
{
      string[]
         cookies = Request.Cookies.AllKeys;
      foreach (string cookie in cookies)
      {
         BulletedList1.Items.Add("Deleting " + cookie);
         Response.Cookies[cookie].Expires = DateTime.Now.AddDays(-1);
      }
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
      <asp:BulletedList ID="BulletedList1" EnableViewState="false" runat="server">
      </asp:BulletedList>
</div>
</form>
</body>
</html>

2011-5-11 22:20 danny
6、使用多值Cookie
根据Cookie规范，单个域名，浏览器不能存储超过20个Cookie。可以通过创建多值Cookie来超越该限制。
多值Cookie是一个包含子键的Cookie。可以根据需要创建任意数量的子键。

setCookieValues.aspx
<%@ Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void btnSubmit_Click(object sender, EventArgs e) {       Response.Cookies["preferences"]["firstName"] = TxtFirstName.Text;       Response.Cookies["preferences"]["lastName"] = txtLastName.Text;       Response.Cookies["preferences"]["favoriteColor"] = txtFavoriteColor.Text;       Response.Cookies["preferences"].Expires = DateTime.MaxValue; }</script><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div>       <asp:Label ID="lblFirstName" runat="server" AssociatedControlID="TxtFirstName" Text="First Name"></asp:Label>       <br />       <asp:TextBox ID="TxtFirstName" runat="server"></asp:TextBox>       <br />       <asp:Label ID="lblLastName" runat="server" AssociatedControlID="TxtFirstName" Text="Last Name"></asp:Label>       <br />       <asp:TextBox ID="txtLastName" runat="server"></asp:TextBox>       <br />       <asp:Label ID="lblFavoriteColor" runat="server" AssociatedControlID="TxtFirstName"          Text="Favorite Color"></asp:Label>       <br />       <asp:TextBox ID="txtFavoriteColor" runat="server"></asp:TextBox>       <br />       <asp:Button ID="btnSubmit" Text="Submit" runat="server"  /> </div> </form></body></html>

查看
GetCookieValues.aspx
<%@ Page Language="C#" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><script runat="server"> protected void Page_Load(object sender, EventArgs e) {       if (Request.Cookies["preferences"] != null)       {          lblFirstName.Text = Request.Cookies["preferences"]["firstName"];          lblLastName.Text = Request.Cookies["preferences"]["lastName"];          lblFavoriteColor.Text = Request.Cookies["preferences"]["favoriteColor"];       } }</script><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"> <title></title></head><body> <form id="form1" runat="server"> <div>       First Name:       <asp:Label ID="lblFirstName" runat="server"></asp:Label>       <br />       Last Name:       <asp:Label ID="lblLastName" runat="server"></asp:Label>       <br />       Favorite Color:       <asp:Label ID="lblFavoriteColor" runat="server"></asp:Label>       <br /> </div> </form></body></html>

2011-5-13 10:59 danny

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8、使用浏览器Cookie

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