如何分隔两个base64字符串？
用逗号或者任意的不在base64字符串内的字符都可以。
All you have to do is to use a separator which is not a valid Basc64 character. Comma is not a base64 character so you can use.
Base64 characters are [0-9a-zA-Z/=+] (all numbers, uppercase, lowercase, forward slash plus and equal sign).
