Establishing the crime of rape in islamic law

How do islamic judicial system establishing that the crime of rape happened. Is the crime assumed to have taken place only on the word of mouth of the woman I read that the word of mouth is taken as evidence so is a innocent man hanged because some random woman with a vendetta said that she is raped by this man. If even a vaginal bleeding is taken as evidence in case of virgin woman it is completely possible that evil woman just shove her vagina with something to build a case and have a innocent man hanged. And even if pregnency is taken as evidence what if that child is from his husband and husband and wife collude to have that man hanged.How a man innocent man prove his innocence.and also Can he take Quranic oath as a last resort.will he be accquited.Otherwise I am seeing a innocent man being hanged which is a grave injustice. Please somebody shed light on this I am so confused right now.