Retrieving Json data from URL - Java

Hollister11

Hi

I'm working on Java using Maven and Jersey.

I need to take a user input (city), create the target URL, and then from that retrieve data as JSON.

That's working fine. The URL builds and outputs as a String. If you paste it into a browser you get the JSON then.

Code here.

My question is how do I return the JSON data to the user from this URL.

The URL for London is

http://api.openweathermap.org/data/2.5/forecast?q=London&&appid=177a4cf0dea72bacc915c0a90eb7b1ac

Buford T Justice

You can use a library like jsoup to get the resultant content back as a string.
Here's a Stack overflow example for JSON https://stackoverflow.com/questions/7133118/jsoup-requesting-json-response

Talisman

Your application should use the JSON API client library to retrieve the data from the OpenWeatherMap service.

Once you have retrieved the data from the API request you should cache it. If you have a web server like Apache/Nginx etc. in front of Jersey it will cache the response for you provided you set the correct Cache-Control headers. The benefit of this is two fold, you reduce the impact of requests on your application and also reduce the volume of requests to the OpenWeatherMap service - such free services are usually request rate limited.

Cache-Control Using Annotations With Jersey

To return a valid content type you need to set the appropriate HTTP header: "Content-Type: application/json"

Code outline without caching:

@Path("/WeatherAPI")
public class Weather {
    @GET
    @Path("/{City}")
    @Produces(MediaType.APPLICATION_JSON)
    public Response getWeather(@PathParam("City") String City) {

        // Call the API
        String OpenWeatherResponse = ...

        // Return the response string
        return Response.status(Status.OK).entity(OpenWeatherResponse).build();

    }
}