将html实体转换为UTF-8，但保留现有的UTF-8
问题描述：
我想将html实体转换为UTF-8，但是 mb_convert_encoding 会销毁已经由UTF-8编码的字符.正确的方法是什么?
I want to convert html entities to UTF-8, but mb_convert_encoding destroys already UTF-8 encoded characters. Whats the correct way?
$text = "äöü ä ö ü ß";
var_dump(mb_convert_encoding($text, 'UTF-8', 'HTML-ENTITIES'));
// string(24) "äöü ä ö ü ß"
答
mb_convert_encoding()不是您要实现的正确功能:您应该真正使用 html_entity_decode()代替，因为它只会转换实际的html实体改为UTF-8，并且不会影响字符串中现有的UTF-8字符.
mb_convert_encoding() isn't the correct function for what you're trying to achieve: you should really be using html_entity_decode() instead, because it will only convert the actual html entities to UTF-8, and won't affect the existing UTF-8 characters in the string.
$text = "äöü ä ö ü ß";
var_dump(html_entity_decode($text, ENT_COMPAT | ENT_HTML401, 'UTF-8'));
给出
string(18) "äöü ä ö ü ß"