我发现自定义函数，解决了我的问题。我用下面的代码：

function my_clickable_links( $text ) {
    $patt = array(
        '%\b(?<!href=[\'"])(?>https?://|www\.)([\p{L}\p{N}]+[\p{L}\p{N}\-]*\.(?:[\p{L}\p{N}\-]+\.)*[\p{L}\p{N}]{2,})(?::\d+)?(?:(?:(?:/[\p{L}\p{N}$_\.\+!\*\'\(\),\%;:@&=-]+)+|/)(?:\?[\p{L}\p{N}$_\.\+!\*\'\(\),\%;:@&=-]+)?(?:#[^\s\<\>]+)?)?(?![^<]*+</a>)%u',
        '%\b(?<!http://)(?<!https://)([\p{L}\p{N}]+[\p{L}\p{N}\-]*\.(?:[\p{L}\p{N}\-]+\.)*(?:ru|com|net))(?::\d+)?(?:(?:(?:/[\p{L}\p{N}$_\.\+!\*\'\(\),\%;:@&=-]+)+|/)(?:\?[\p{L}\p{N}$_\.\+!\*\'\(\),\%;:@&=-]+)?(?:#[^\s\<\>]+)?|\b)(?![^<]*+</a>)%u'
    );
    $repl = array(
        '<a href="$0">$1</a>',
        '<a href="http://$0">$1</a>'
    );
    $text = preg_replace($patt, $repl, $text);
    echo $text;
}
add_filter( 'the_content', 'my_clickable_links', 12 );