Sun's implementation of Java SE 6 includes a light-weight HTTP server API and implementation. This is used internally by other components of Java SE, but it can just as easily be used for user applications to deploy simple HTTP server applications. The relevant API packages are:
The first of these contains the API itself, and the second contains an SPI (Service Provider Interface) which allows alternative implementations to be plugged in. You are more likely to be interested in the first package.
You are probably wondering already about the package names, and why they are com.sun.httpserver rather than something like java.net.httpserver. What this distinction means, is that the API and implementation are a fully supported, publicly accessible component of Sun's implementation of Java SE 6. It does mean however, that the packages are not formally part of the Java SE platform, and are therefore not guaranteed to be available on all other (non Sun) implementations of Java SE 6.
So, what can you do with the HTTP server ?
First, the package allows programmers to create simple embedded http and https applications. The API is similar in some respects to the servlet API in Java EE, but this API is more light-weight and does not provide the facilities/services that the servlet container environment provides.
It does have some innovations like a pluggable thread model. What this means is that the server does not create threads for handling incoming Http requests. Instead, the management of threads is delegated to an Executor object provided by the application. A number of off the shelf Executor implementations are provided in Java SE 6, and the programmer can choose one (or roll your own).
The following table shows the main classes and interfaces that a programmer needs to know about for programming a HTTP server.
|Class/interface||What does it do?|
||Listens on a particular port number and address for incoming Http requests|
||Same as for HttpServer except for Https requests|
||Programmer implements this. Handler is called to handle each incoming Http request|
||Encapsulates all of the information about a Http request and the corresponding response|
||Represents one Http application on a HttpServer instance. It is identified by the URI path to the application, and has a HttpHandler associated|
There are a number of other auxiliary classes in addition to the ones mentioned above. They provide services like basic http authentication and a filtering mechanism, that can be applied to all incoming requests.
So that is a very brief overview of the Http server API. I plan to augment this with some code samples of how to use the API, how to configure the use of SSL etc.