我正在尝试以正确的方式显示此德语字符，如果我不使用htmlentities()，则输出为unabh�ngig，但当我尝试使用htmlentities()时，这个词不见了，为什么？
<?php
$str = htmlentities("unabhängig");
?>
<!DOCTYPE html>
<html lang="en">
<head>
<title>Test</title>
<meta charset='utf-8'>
</head>
<body>
</body>
<div><?php echo $str;?></div>
我对ü、ä等也有同样的问题
在选择数据库之后，我实现了这两行：
mysql_query("SET NAMES 'utf8'");
mysql_query("SET CHARACTER SET 'utf8'");
如这里所建议的：http://www.flashhilfe.de/forum/serverseitige-programmierung/php-mysql-wie-utf-8-beim-connect-festlegen-225225-225225.html
最佳，Yannis
通过确保使用HTTP头将字符集设置为utf-8，您应该能够在不单独编码的情况下发送ü。
如果由于某些原因您无法做到这一点，请使用：
Ü = Ü
或
ü = ü
这是字符集的格式：
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
请确保您的编码不是由htaccess或apache强制执行的。查看网站时，请检查浏览器中选择的编码是什么，如果不是utf-8，则为强制编码。如果强制，您可以将其添加到htaccess
AddDefaultCharset UTF-8
确保您的数据库表在utf-8 中
确保您与数据库的连接处于utf-8中http://php.net/manual/en/function.mysql-set-charset.php
mysql_query("SET character_set_results = 'utf8', character_set_client = 'utf8', character_set_connection = 'utf8', character_set_database = 'utf8', character_set_server = 'utf8'", $conn);
您可以将UTF-8编码传递给htmlentities，使其使用正确的编码。或者您可以使用htmlspecialcharshttp://php.net/manual/en/function.htmlentities.php
如果你不想担心这么多不同的字符集编码，或者如果htmlentities不适合你，这里有另一种选择：我使用了mysqli DB连接（和PHPV5）Form post来编写/插入MySQl-DB。
$Notes = $_POST['Notes']; //can be text input or textarea.
$Notes = str_replace('"', '"', $Notes); //double quotes for mailto: emails.
$von = array("ä","ö","ü","ß","Ä","Ö","Ü"," ","é"); //to correct double whitepaces as well
$zu = array("ä","ö","ü","ß","Ä","Ö","Ü"," ","é");
$Notes = str_replace($von, $zu, $Notes);
echo " Notes:".$Notes."<br>" ;
$Notes = mysqli_real_escape_string($link, $Notes); //for recommended mysqli DB connection.
//$Notes = mysql_real_escape_string($Notes); //for old deprecated mysql DB connection.
// mysqli_real_escape_string Escapes special characters in a string for use in an SQL statement
echo " Notes:".$Notes ; //ready for inserting
enter code here
//Optional:
$charset = mysqli_character_set_name($link); //only works for mysqli DB connection
printf ("To check your character set but not necessary %s'n",$charset);