如果我理解正确，您首先需要将用户重定向到http://domain.com/cpt1/%postname%/ 之后，您需要重写URL以获得正确的帖子并避免404错误。

所以你来了：

add_action( \'template_redirect\', \'redirect_postid_to_postname\' );

function redirect_postid_to_postname() {

    $uri = $_SERVER[\'REQUEST_URI\'];

    // Checks if the URI matches what we want. This means the URL should be sth like http://example.com/cpt1/POST_ID
    if ( !preg_match( "/^\\/cpt1\\/(\\d+)/", $uri, $matches ) ) {
        return;
    }

    $post_id = $matches[1];

    // Checks if $post_id is actually an existent post ID.
    $post_obj = get_post( $post_id );

    // Checks if a post object was retrieved for the given post ID.
    if ( !$post_obj ) {
        return;
    }

    $post_name = $post_obj->post_name; // Keeps post slug.
    $site_url = get_site_url(); // Keeps site URL (it\'s supposed to be retrieved without trailing slash).
    $location = $site_url . "/cpt1/$post_name"; // Builds the new URL to redirect the user to.

    // Redirects!
    wp_redirect( $location, 302 );

    exit;

}

add_action( \'init\', \'rewrite_custom_postname\', 100 );

function rewrite_custom_postname() {

    $uri = $_SERVER[\'REQUEST_URI\'];

    // Checks if the URI matches what we want. This means the URL should be sth like http://example.com/cpt1/POST_NAME
    if ( !preg_match( "/^\\/cpt1\\/(.+)/", $uri, $matches ) ) {
        return;
    }

    $post_name = $matches[1];

    $query_args = array(
        \'name\'        => $post_name,
        \'post_type\'   => \'cpt1\',
        \'post_status\' => \'publish\',
        \'numberposts\' => 1
    );

    $post_obj = get_posts( $query_args );

    // Checks if a post object was retrieved for the given query arguments.
    if ( !$post_obj ) {
        return;
    }

    $post_id = $post_obj[0]->ID;

    $regex = "^cpt1/{$matches[1]}";
    $query = "index.php?p=$post_id";
    $after = "top";

    add_rewrite_rule( $regex, $query, $after );

}

IMPORTANT!
如果您仍在使用Permalink管理器，并且还将uri从%postname%更改为%post\\u id%，则可能会创建无限的重定向循环，因此请小心。