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thinkPHP cookie读取报错,上代码

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2016-06-06 20:34:361560browse

<code>setcookie('name',234,time()+10,'/');


//$b = $_COOKIE['name'];

echo $_COOKIE['name'];
</code>

为什么这个代码,第一次执行的时候报错,会报
Notice: Undefined index: name in D:\wamp\Apache\htdocs\test.php on line 10
未定义的索引 name ,我明明是先设置了COOKIE 再读取的啊?求详细解释

回复内容:

<code>setcookie('name',234,time()+10,'/');


//$b = $_COOKIE['name'];

echo $_COOKIE['name'];
</code>

为什么这个代码,第一次执行的时候报错,会报
Notice: Undefined index: name in D:\wamp\Apache\htdocs\test.php on line 10
未定义的索引 name ,我明明是先设置了COOKIE 再读取的啊?求详细解释

cookie 设置不是立即生效的, setcookie() 只是在 response header 头里加上 Set-Cookie 头,例如:

<code>Set-Cookie: PHPSESSID=tbmh6ussjmqrblhth75qb9h2l0; path=/
</code>

这个响应到达客户端, Cookie 设置成功后, 下次 客户端的请求就会在 Header 里带上这个头:

<code>Cookie: PHPSESSID=tbmh6ussjmqrblhth75qb9h2l0
</code>

此时才能通过 $_COOKIE 取到这个值。这就是为什么:

<code>they can be accessed on the next page load with the $_COOKIE or $HTTP_COOKIE_VARS 
</code>

<code>Once the cookies have been set, they can be accessed on the next page load with the $_COOKIE or $HTTP_COOKIE_VARS 
</code>

php对setcookie函数的说明。

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