title: How to create simple JSON API, e.g. with Jetty?
body: <p>this seems pretty basic, but I am rather new to web development so I am a bit stuck here. I have MongoDB running on the backend, which contains geo-spatial objects that in the front end should be displayed on a map. The communication between backend and web frontend is where I have knowledge gaps.</p>
  
  <p>The user should be able to zoom to an area on a map that he is interested in, then press "Search". The backend would then find every entry in the database that has coordinates that are on the users current screen. It would transmit these to the frontend, ideally as a list of JSON objects. The frontend displays these on a map.</p>
  
  <p>I have a front end mock up, code that puts data into MongoDB and code that queries MongoDB. I know that I am missing a server that can be queried from the frontend. I thought I use Jetty. But what do I need to do then? I guess I need Jetty to provide a JSON API that I can query from JavaScript. Could someone point me to the Jetty class or interface that I need to implement and maybe give a few lines of code on how to query this from JavaScript?  </p>