Miscellaneous Tools

Java Tools Tutorials - Herong's Tutorial Examples

∟Miscellaneous Tools

This chapter provides provides a tutorial example on how to use 'jwebserver' command to launch the Java Simple Web Server.

What Is "jwebserver"? - "jwebserver" is the command that launches the Java Simple Web Server provided in JDK since Java 18.

Main features of the Java Simple Web Server are:

Only static files are supported. Server side scripting is not supported.
Only GET and HEAD methods are supported. POST method is not supported.
Only HTTP/1.1 is supported. HTTP/2 and HTTPS are not supported.
MIME type is automatically determined based on the file name extension of the requested file. For example, .html files are served as text/html. .java files are served as text/plain. .json files are served as application/json.
Logging is supported in 3 levels: NONE, INFO, and VERBOSE.

If you have %java_home%\bin directory included in "path" the environment variable, you can run "jwebserver --help" to get the usage information:

herong> jwebserver --help

Usage: jwebserver [-b bind address] [-p port] [-d directory]
                  [-o none|info|verbose] [-h to show options]
                  [-version to show version information]
Options:
-b, --bind-address  - Address to bind to. Default: 127.0.0.1 (loopback).
                      For all interfaces use "-b 0.0.0.0" or "-b ::".
-d, --directory     - Directory to serve. Default: current directory.
-o, --output        - Output format. none|info|verbose. Default: info.
-p, --port          - Port to listen on. Default: 8000.
-h, -?, --help      - Prints this help message and exits.
-version, --version - Prints version information and exits.
To stop the server, press Ctrl + C.

Here is what I did to try the "jwebserver" tool.

1. Create a sub-directory "www" with the following files:

herong> cd www
herong> dir

   index.html
   sample.json
   sample.png
   sample.xml

2. Start the Java Simple Web Server:

herong> jwebserver -o verbose

Binding to loopback by default.
For all interfaces use "-b 0.0.0.0" or "-b ::".
Serving /Users/herong/www and subdirectories on 127.0.0.1 port 8000
URL http://127.0.0.1:8000/

3. Request the default page in a Web browser at http://127.0.0.1:8000/. I see "Hello world!" displayed. "jwebserver" printed the following logging messages:

127.0.0.1 - - [20/May/2023:08:21:26 -0400] "GET / HTTP/1.1" 200 -
Resource requested: /Users/herong/www
> Accept-encoding: gzip, deflate
> Accept: text/html,application/xhtml+xml,application/xml;...
> Connection: keep-alive
> Host: 127.0.0.1:8000
> User-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) ...
> Accept-language: en-us
> Upgrade-insecure-requests: 1
>
< Date: Sat, 20 May 2023 12:21:26 GMT
< Last-modified: Sat, 20 May 2023 12:21:22 GMT
< Content-type: text/html
< Content-length: 74

4. Request the XML sample page in a Web browser at http://127.0.0.1:8000/sample.xml. I see the XML document displayed:

<html>
<head>
<title>Hello</title>
</head>
<body>Hello world!</body>
</html>

5. Request the PNG sample page in a Web browser at http://127.0.0.1:8000/sample.png. I see the sample image displayed.

Note that "jwebserver" is located in the jdk.httpserver module. The Java Simple Web Server is based on the web server implementation in the com.sun.net.httpserver package and the com.sun.net.httpserver.SimpleFileServer class.

You can actually launch the Java Simple Web Server directly from the jdk.httpserver module:

herong> java -m jdk.httpserver

Binding to loopback by default.
For all interfaces use "-b 0.0.0.0" or "-b ::".
Serving /Users/herong/www and subdirectories on 127.0.0.1 port 8000
URL http://127.0.0.1:8000/