Base64是MIME邮件中常用的编码方式之一。它的主要思想是将输入的字符串或数据编码成只含有{ A - Z , a - z , 0 - 9 , + , / }这64个可打印字符的串，故称为“Base64”。-Base64 is a MIME message encoding one of the ways commonly used. Its main idea is to input data encoded into a stri