The thing about Jayce is that he has absurd AD and crit scaling, and can focus solely on those 2 stats + armor penetration and CDR to do absurd damage lategame.
No attack speed necessary, so put those Phantom Dancers away.
Jayce has literally no weak points in his game.
He is incredibly strong throughout early and mid game, and hyperscales into lategame with just IE's.
Video of a Jayce literally 1-shotting a Vayne with hypercharge alone.
Like Konfetarius said, don't bother with Trinity Force or high tank stats.
Just get IE, some CDR, and armor pen, and continue to stack AD either through the hybrid AD/defensive items or more IE's, with an Executioners Calling as your lifesteal option.