AutoWiki is a Bukkit/Spigot plugin that allows players to look up topics from the Minecraft Wiki and get books with information about them.
It uses the JSoup library to parse the wiki and requires Spigot 1.8.8 to generate books, but with a few minor changes should be able to work with any other versions.
This plugin is mostly for demonstration, but may be able to serve a purpose so feel free to browse through the code.