SimpleFileServer (Java SE 25 & JDK 25)
Description: declaration: module: jdk.httpserver, package: com.sun.net.httpserver, class: SimpleFileServer
Keywords: com.sun.net.httpserver.SimpleFileServer class

# Class SimpleFileServer

java.lang.Object
com.sun.net.httpserver.SimpleFileServer

public final class SimpleFileServer extends Object
A simple HTTP file server and its components (intended for testing, development and debugging purposes only).

A simple file server is composed of three components:

- an `HttpServer` that is bound to a given address,
- an `HttpHandler` that serves files from a given directory path, and
- an optional `Filter` that prints log messages relating to the exchanges handled by the server.

The individual server components can be retrieved for reuse and extension via the static methods provided.

## Simple file server

The `createFileServer` static factory method returns an `HttpServer` that is a simple out-of-the-box file server. The server comes with an initial handler that serves files from a given directory path (and its subdirectories). The output level determines what log messages are printed to `System.out`, if any.

Example of a simple file server:

       var addr = new InetSocketAddress(8080);
       var server = SimpleFileServer.createFileServer(addr, Path.of("/some/path"), OutputLevel.INFO);
       server.start();

## File handler

The `createFileHandler` static factory method returns an `HttpHandler` that serves files and directory listings. The handler supports only the HEAD and GET request methods; to handle other request methods, one can either add additional handlers to the server, or complement the file handler by composing a single handler via `HttpHandlers.handleOrElse(Predicate, HttpHandler, HttpHandler)`.

Example of composing a single handler:

       var handler = HttpHandlers.handleOrElse(
           (req) -> req.getRequestMethod().equals("PUT"),
           (exchange) -> {
               // validate and handle PUT request
           },
           SimpleFileServer.createFileHandler(Path.of("/some/path")))
       );

## Output filter

The `createOutputFilter` static factory method returns a `post-processing filter` that prints log messages relating to the exchanges handled by the server. The output format is specified by the `outputLevel`.

Example of an output filter:

       var filter = SimpleFileServer.createOutputFilter(System.out, OutputLevel.VERBOSE);
       var server = HttpServer.create(new InetSocketAddress(8080), 10, "/some/path/", new SomeHandler(), filter);
       server.start();

## jwebserver Tool

A simple HTTP file server implementation is provided via the `jwebserver` tool.

Tool Guides:
  jwebserver
Since:
  18

- ## Nested Class Summary

  Nested Classes
  Modifier and Type
  Class
  Description
  `static enum`
  `SimpleFileServer.OutputLevel`
  Describes the log message output level produced by the server when processing exchanges.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `static HttpHandler`
  `createFileHandler(Path rootDirectory)`
  Creates a file handler that serves files from a given directory path (and its subdirectories).
  `static HttpServer`
  `createFileServer(InetSocketAddress addr, Path rootDirectory, SimpleFileServer.OutputLevel outputLevel)`
  Creates a file server that serves files from a given path.
  `static Filter`
  `createOutputFilter(OutputStream out, SimpleFileServer.OutputLevel outputLevel)`
  Creates a post-processing Filter that prints log messages about exchanges.

  ### Methods declared in class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Method Details

  - ### createFileServer

    public static HttpServer createFileServer(InetSocketAddress addr, Path rootDirectory, SimpleFileServer.OutputLevel outputLevel)
    Creates a file server that serves files from a given path.

    The server is configured with an initial context that maps the URI `path` to a file handler. The file handler is created as if by an invocation of `createFileHandler(rootDirectory)`, and is associated to a context created as if by an invocation of `createContext("/")`. The returned server is not started.

    An output level can be given to print log messages relating to the exchanges handled by the server. The log messages, if any, are printed to `System.out`. If `OutputLevel.NONE` is given, no log messages are printed.

    Parameters:
      `addr` - the address to listen on
      `rootDirectory` - the root directory to be served, must be an absolute path
      `outputLevel` - the log message output level
    Returns:
      an HttpServer
    Throws:
      `IllegalArgumentException` - if root does not exist, is not absolute, is not a directory, or is not readable
      `UncheckedIOException` - if an I/O error occurs
      `NullPointerException` - if any argument is null

  - ### createFileHandler

    public static HttpHandler createFileHandler(Path rootDirectory)
    Creates a file handler that serves files from a given directory path (and its subdirectories).

    The file handler resolves the request URI against the given `rootDirectory` path to determine the path `p` on the associated file system to serve the response. If the path `p` is a directory, then the response contains a directory listing, formatted in HTML, as the response body. If the path `p` is a file, then the response contains a "Content-Type" header based on the best-guess content type, as determined by an invocation of getContentTypeFor, on the system-wide `mimeTable`, as well as the contents of the file as the response body.

    The handler supports only requests with the HEAD or GET method, and will reply with a `405` response code for requests with any other method.

    Parameters:
      `rootDirectory` - the root directory to be served, must be an absolute path
    Returns:
      a file handler
    Throws:
      `IllegalArgumentException` - if rootDirectory does not exist, is not absolute, is not a directory, or is not readable
      `NullPointerException` - if the argument is null

  - ### createOutputFilter

    public static Filter createOutputFilter(OutputStream out, SimpleFileServer.OutputLevel outputLevel)
    Creates a post-processing Filter that prints log messages about exchanges. The log messages are printed to the given `OutputStream` in `UTF-8` encoding.
    API Note:
      To not output any log messages it is recommended to not use a filter.
    Parameters:
      `out` - the stream to print to
      `outputLevel` - the output level
    Returns:
      a post-processing filter
    Throws:
      `IllegalArgumentException` - if `OutputLevel.NONE` is given
      `NullPointerException` - if any argument is null