PHP中的$_COOKIE与urlencode/decode的关系

有些base64编码会产生"+"（加号），放到用java进行base64编码后放到cookies里面，然后PHP读取cookies时候，base64编码中的"+"变成了"_"（空格），原因如下：

PHP 手册里面提到：

Note that the value portion of the cookie will automatically be urlencoded when you send the cookie, and when it is received, it is automatically decoded and assigned to a variable by the same name as the cookie name. If you don't want this, you can use setrawcookie() instead if you are using PHP 5.

解决方法：

JAVA设置cookies前，先对base64编码进行urlencode。或者把base64编码中的"+"替换成其他字符，PHP解密前替换回就可以了。