How to get rid of hate?

I have a friend that I met few years back. He always look polite, look decent, and look helping others a lot. I did him a lot of helps that no friend would do to him. Later, when I needed helps he really, replied me with very bad words, which I never thought he can even talk like that. This thing really becoming something that I cannot forget. It seems I suffer it a lot. I was thinking how to get rid of this for a long time now. What are the practical measures in Buddhism to get rid of such hate inside one's inside. Thank you.