How to Get Air Quality Index Using AirVisual API in Java

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.