How to look up ZIP/Postal Code by City using Google Maps API?

How can I extract a Postal Code or ZIP of a place by giving Google Maps a city on the map?

Basically I'm looking for a 开发者_JAVA技巧free verification service for checking completed addresses for accurate details.

I seem to remember the maps API can somehow provide a geographical point when given an address. Now I'm searching for a slightly reversed situation in order to validate the postal code typed in with a city.

You need to Geocode the address to get best match coordinates

and then Reverse Geocode the coordinates to compare zip.