如果你只是在寻找一个实际的正则表达式，允许各种点，下划线和破折号，它如下:[a-zA-z0-9.-]+\@[a-zA-z0-9.-]+.[a-zA-Z]+。这将允许像tom_anderson.1-neo@my-mail_matrix.com这样看起来相当愚蠢的电子邮件被验证。

根据我的经验，regex解决方案有太多的假阳性，而filter_var()解决方案有假阴性(特别是对于所有新的tld)。

相反，最好是确保地址具有电子邮件地址的所有必需部分(用户、“@”符号和域)，然后验证域本身是否存在。

无法确定(服务器端)外部域是否存在电子邮件用户。

这是我在Utility类中创建的一个方法:

public static function validateEmail(string $email): bool {

    // SET INITIAL RETURN VARIABLE
    // ENSURE -> EMAIL ISN'T EMPTY | AN @ SYMBOL IS PRESENT 

        $emailIsValid = FALSE;

        if (
            !empty($email) &&
            strpos($email, '@') !== FALSE
        ) {

            // GET EMAIL PARTS

                $email  = explode('@', $email);
                $user   = $email[0];
                $domain = $email[1];

            // VALIDATE EMAIL ADDRESS

                if (
                    count($email) === 2 &&
                    !empty($user) &&
                    !empty($domain) &&
                    checkdnsrr($domain)
                ) {
                    $emailIsValid = TRUE;
                }
        }

    // RETURN RESULT

        return $emailIsValid;
}

看完这里的答案后，我得出了以下结论:

public static function isValidEmail(string $email) : bool
{
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        return false;
    }

    //Get host name from email and check if it is valid
    $email_host = array_slice(explode("@", $email), -1)[0];

    // Check if valid IP (v4 or v6). If it is we can't do a DNS lookup
    if (!filter_var($email_host,FILTER_VALIDATE_IP, [
        'flags' => FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE,
    ])) {
        //Add a dot to the end of the host name to make a fully qualified domain name
        // and get last array element because an escaped @ is allowed in the local part (RFC 5322)
        // Then convert to ascii (http://us.php.net/manual/en/function.idn-to-ascii.php)
        $email_host = idn_to_ascii($email_host.'.');

        //Check for MX pointers in DNS (if there are no MX pointers the domain cannot receive emails)
        if (!checkdnsrr($email_host, "MX")) {
            return false;
        }
    }

    return true;
}

使用以下代码:

// Variable to check
$email = "john.doe@example.com";

// Remove all illegal characters from email
$email = filter_var($email, FILTER_SANITIZE_EMAIL);


// Validate e-mail
if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
  echo("Email is a valid email address");
}

如果你只是在寻找一个实际的正则表达式，允许各种点，下划线和破折号，它如下:[a-zA-z0-9.-]+\@[a-zA-z0-9.-]+.[a-zA-Z]+。这将允许像tom_anderson.1-neo@my-mail_matrix.com这样看起来相当愚蠢的电子邮件被验证。

您可以为此使用filter_var。

<?php
   function validateEmail($email) {
      return filter_var($email, FILTER_VALIDATE_EMAIL);
   }
?>