algj

            // don't forget to add craftbukkit.jar of your server version. seriously.

            Location loc = player.getLocation();
            World world = player.getWorld();
            Block block = world.getBlockAt(loc);
            BlockState state = block.getState();
            state.setType(Material.SPAWNER);
            state.update(true);
            CreatureSpawner data = (CreatureSpawner) block.getState();
            data.setRequiredPlayerRange(0);