In 2007 my ex filed a restraining order implying I was harassing her and while arguing allegedly grabbed her wrists. It was an unhealthy relationship. She was vindictive and manipulative. The judge didn't let me talk during court. We saw him for less than 2 min and the restraining order was placed. The restraining order scoured on 3/7/2010. I was 21 when this happened and I'm 27 now.
Will this affect my chances of becoming a police officer.

It could. It shouldn't. It probably won't. It wasn't very recent. You weren't charged with a crime. But if there are a bunch of police reports out there involving arguments, disturbances, or fights between you and your ex or involving you as a suspect, especially recently, then it probably will affect your chances more.

A restraining order isn't a conviction. It shouldn't have any affect.