java api for simple gis computations

I am trying to develop some simple location logic in the server-side portion of a java servlet-based webapp.

There are really just two operations that I'm interested in:

1. Given a start point (lat/long) s1, distance d, and search point (also lat/long) s2, determine if the 开发者_开发百科s2 is within d distance from s1.

2. Given two points (lat/long), determine the distance between them.

Does anyone have recommendations of a simple java API that supports these operations?

Thanks!

• There is geotools a, in their own words, actually quite HUGE, package.

• Some general latitude/longitude related scripts, e.g. Haversine formula to calculate the great-circle distances between the two points – that is, the shortest distance over the earth’s surface.