在OpenLayers 3中设置视图范围

I've just started having a look at OpenLayers 3 and am attempting to zoom to a single feature whose extent is to be a geoJSON object sent by the server (which will change at each refresh, so I can't hard code the zoom/central point). I would like this to happen preferably as soon as the page loads, but I'm struggling to get it to work.I've just started having a look at OpenLayers 3