Set Up HTTP Client
- In Java, you can use libraries like `HttpURLConnection`, Apache HttpClient, or OkHttp to make HTTP requests. The newer `java.net.http.HttpClient` introduced in Java 11 is also a great option.
- For this example, we will use `java.net.http.HttpClient`.
import java.net.http.HttpClient;
HttpClient client = HttpClient.newHttpClient();
Construct the Request
- AirVisual API provides a variety of endpoints. For this example, use the "nearest\_city" endpoint to get the air quality information of the nearest city based on your location.
- You will need an API key that you got during the set-up process.
import java.net.http.HttpRequest;
import java.net.URI;
String apiKey = "your_api_key";
String url = String.format("https://api.airvisual.com/v2/nearest_city?key=%s", apiKey);
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create(url))
.GET()
.build();
Send the Request
- Use `HttpClient` to send the built request. This can be done synchronously or asynchronously.
- In this example, we will use a synchronous request with `send` method.
import java.net.http.HttpResponse;
HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
Process the Response
- The API will return a JSON response that contains the air quality information. You need to parse this JSON to extract relevant data.
- Use a library like `org.json` or `Gson` to process the JSON object in your Java code.
import org.json.JSONObject;
String responseBody = response.body();
JSONObject jsonObj = new JSONObject(responseBody);
int aqi = jsonObj.getJSONObject("data").getJSONObject("current").getJSONObject("pollution").getInt("aqius");
System.out.println("The Air Quality Index (AQI) is: " + aqi);
Error Handling
- It's important to handle potential exceptions, such as `IOException`, `InterruptedException`, and JSON parsing exceptions.
- Ensure your code gracefully manages different kinds of issues that might arise during the HTTP request or response processing.
try {
//... code to make request ...
} catch (IOException | InterruptedException e) {
e.printStackTrace();
System.out.println("An error occurred while fetching the Air Quality Index.");
} catch (JSONException e) {
System.out.println("Error parsing JSON response.");
}
Optimize and Extend
- Consider adding support for additional error handling, logging, and code to manage retries in case of temporary network issues.
- Extend your implementation to handle different endpoints provided by AirVisual API if needed.
- Ensure your application complies with API limits to avoid being blocked due to excessive requests.
These steps provide a comprehensive guide on how to retrieve Air Quality Index data using the AirVisual API in Java.
