问题
Is it possible to know the city name based on IP address in java?
回答1:
are you using jsp or what ? for city name over client side you can use google's API which will return you the geographical details of the user mapped with the IP. As google's documentation say you can get the following
When populated, the google.loader.ClientLocation object is populated with the following metro-level granularity properties:
* ClientLocation.latitude — supplies the low resolution latitude associated with the client's IP address
* ClientLocation.longitude — supplies the low resolution longitude associated with the client's IP address
* ClientLocation.address.city — supplies the name of the city associated with the client's IP address
* ClientLocation.address.country — supplies the name of the country associated with the client's IP address
* ClientLocation.address.country_code — supplies the name of the ISO 3166-1 country code associated with the client's IP address
* ClientLocation.address.region — supplies the country specific region name associated with the client's IP address
for further reference see the complete documentation at http://code.google.com/apis/ajax/documentation/
回答2:
You have to use a service such as hostip.info that maps an IP to its physical location, and offer an API to developers to simplify the task.
There are many other services, paid and for free, that you can find at Google.
回答3:
If an online API as the others have suggested won't suit your application, I have previously successfully used MaxMind GeoLite City, which comes with a Java API (among many others). Just download the database files, point your API code at them, and off you go. Simple and straightforward.
来源：https://stackoverflow.com/questions/2257170/how-to-get-city-name-based-on-ip-address-in-java