如何获取多字节字符串的字节大小

string = "你好，世界！"
byte_size = len(string.encode('utf-8'))
print(byte_size)

String string = "你好，世界！";
int byteSize = string.getBytes("UTF-8").length;
System.out.println(byteSize);

const string = "你好，世界！";
const byteSize = new Blob([string]).size;
console.log(byteSize);

string str = "你好，世界！";
byte[] byteArray = Encoding.UTF8.GetBytes(str);
int byteSize = byteArray.Length;
Console.WriteLine(byteSize);

$string = "你好，世界！";
$byteSize = strlen(mb_convert_encoding($string, 'UTF-8', 'auto'));
echo $byteSize;