alibaba/nacos · error · NestedIoException

Invalid URI [{url}]

Error message

Invalid URI [{url}]

What it means

Thrown by AbstractResource.getUri() when getUrl() succeeds but ResourceUtils.toUri(url) raises URISyntaxException — the URL string is not a valid URI. Wrapped as NestedIoException. It indicates a malformed URL (illegal characters, bad encoding) rather than a missing resource.

Source

Thrown at common/src/main/java/com/alibaba/nacos/common/packagescan/resource/AbstractResource.java:124

     * This implementation throws a FileNotFoundException, assuming
     * that the resource cannot be resolved to a URL.
     */
    @Override
    public URL getUrl() throws IOException {
        throw new FileNotFoundException(getDescription() + " cannot be resolved to URL");
    }

    /**
     * This implementation builds a URI based on the URL returned
     * by {@link #getUrl()}.
     */
    @Override
    public URI getUri() throws IOException {
        URL url = getUrl();
        try {
            return ResourceUtils.toUri(url);
        } catch (URISyntaxException ex) {
            throw new NestedIoException("Invalid URI [" + url + "]", ex);
        }
    }

    /**
     * This implementation throws a FileNotFoundException, assuming
     * that the resource cannot be resolved to an absolute file path.
     */
    @Override
    public File getFile() throws IOException {
        throw new FileNotFoundException(getDescription() + " cannot be resolved to absolute file path");
    }

    /**
     * This implementation returns {@link Channels#newChannel(InputStream)}
     * with the result of {@link #getInputStream()}.
     * This is the same as in {@link Resource}'s corresponding default method
     * but mirrored here for efficient JVM-level dispatching in a class hierarchy.
     */

View on GitHub (pinned to 9b989acdf1)

Solutions

  1. URL-encode path components when constructing the resource URL so getUri() parses cleanly.
  2. Catch NestedIoException/URISyntaxException and fall back to using the URL directly instead of URI.
  3. Sanitize the path (remove/encode spaces) before creating the resource.
  4. Use ResourceUtils.toUri after pre-encoding with URLEncoder on the relevant segment.

Example fix

// before
Resource res = new UrlResource("file:/C:/Program Files/app/conf.json");
URI u = res.getUri(); // NestedIoException: Invalid URI (space)

// after
String encoded = "file:///C:/Program%20Files/app/conf.json";
Resource res = new UrlResource(encoded);
URI u = res.getUri();
Defensive patterns

Strategy: validation

Validate before calling

// pre-encode path segments containing illegal URI characters
String safe = rawPath.replace(" ", "%20");
Resource res = new UrlResource(safe);
URI u = res.getUri();

Type guard

boolean isParsableUri(URL url) {
    try { url.toURI(); return true; }
    catch (URISyntaxException e) { return false; }
}

Try / catch

try {
    URI u = resource.getUri();
} catch (NestedIoException e) {
    if (e.getCause() instanceof URISyntaxException) {
        log.error("Malformed URL — encode path components: {}", e.getMessage());
    }
    throw e;
}

Prevention

When it happens

Trigger: Calling resource.getUri() on a resource whose URL contains characters illegal in a URI (spaces, unencoded non-ASCII, stray characters) so java.net.URI rejects it.

Common situations: File paths with spaces or non-ASCII on Windows; custom URL schemes with unencoded components; a classpath URL containing characters that survive as URL but fail URI parsing; a misconstructed resource path.

Related errors

AI-assisted analysis of alibaba/nacos@9b989acdf1 (2026-08-14). Data as JSON: /api/errors/5bc1a19e1de6b62e. Report an issue: GitHub.