php连接数据库不支持中文怎么办

mysqli_query($conn , "set names utf8");

header("content-Type: text/html; charset=utf-8");

<?php
header("content-Type: text/html; charset=utf-8");
$servername = "127.0.0.1";
$username = "root";
$passWord = "";
$dbname = "poet";
 
// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
    die("连接失败: " . mysqli_connect_error());
}
 echo "连接成功";
mysqli_query($conn , "set names utf8");
$sql = "SELECT * FROM dufu";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
    // 输出数据
    while($row = mysqli_fetch_assoc($result)) {
        echo
         "poetname: " . $row["poetname"]. "<br>". 
         "content: " . $row["content"]. "<br>";
    }
} else {
    echo "0 结果";
}
mysqli_close($conn);
?>