$a4 = base64_decode("MzYwzsDKvw==");
$a5 = iconv("GBK","UTF-8",$a4);
echo $a5;
echo base64_encode(iconv("UTF-8","GBK","开心水果也疯狂"))
$a4 = base64_decode("MzYwzsDKvw==");
$a5 = iconv("GBK","UTF-8",$a4);
echo $a5;
echo base64_encode(iconv("UTF-8","GBK","开心水果也疯狂"))