Try a Reset...
Reset ( No Data will be Lost )
Press and hold the Sleep/Wake button and the Home button at the same time for at least ten seconds, until the Apple logo appears. Release the Buttons.
If resetting the iPad doesn't help, start experimenting with the accessories .... Try another cable - try another power adapter if you can get your hands on one .... At an Apple Store perhaps if you don't know anybody else with an iPad. Try another wall socket as well. Rule out all of those possibilities. You can even try restoring the iPad iOS and see if the iPad will charge properly
If none of that works, take the iPad to an Apple Store for evaluation.