“When Henry Cavill signed on to play Superman in Zack Snyder’s Man of Steel , he signed on for one hell of a commitment.”
He’s not only going to be in the movies, but also “plays” Superman in the whole DC Universe: he’s basically going to be the one and only Superman, not just for one time, like Edward Norton’s off and on appearance as The Hulk. According to the source article, he’ll be Superman until 2019.
But honestly, how long is that, really? Especially since there’s only like, one DC movie released every year, so what, that’s 4 more movies, tops? Maybe 5? I dunno, considering how much money the movies net, then at least he’ll be rich.