Set Up Your Java Environment
- Ensure that you have a working Java development environment. If you don't have Maven installed, consider installing it as it will help in managing dependencies efficiently.
- Decide if you're going to work with a specific IDE like IntelliJ IDEA, Eclipse, or use a simple text editor with command line compilation.
Add Required Dependencies
- Use Maven to manage dependencies. Add the following dependencies to your `pom.xml` for HTTP requests and JSON parsing.
<dependencies>
<!-- Add HTTP client dependecy -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.13</version>
</dependency>
<!-- Add JSON parser dependency -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.11.3</version>
</dependency>
</dependencies>
- Once you add these, make sure to update Maven to fetch the appropriate libraries.
Build the HTTP Request
- Create a method to build and send HTTP requests to the Polygon.io API endpoint for stock quotes. Make sure you replace "YOUR_API_KEY" with your actual API key received from Polygon.io.
import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import java.io.IOException;
public class PolygonApiFetcher {
private static final String API_KEY = "YOUR_API_KEY";
private static final String BASE_URL = "https://api.polygon.io/v1/last/stocks/";
public String getStockQuote(String stockTicker) throws IOException {
String url = BASE_URL + stockTicker + "?apiKey=" + API_KEY;
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpGet request = new HttpGet(url);
try (CloseableHttpResponse response = httpClient.execute(request)) {
HttpEntity entity = response.getEntity();
if (entity != null) {
return EntityUtils.toString(entity);
}
}
return null;
}
}
- This method creates an HTTP client, builds a GET request, and retrieves the quote data as a string.
Parse the JSON Response
- Once you receive the response as a string, parse it using Jackson or any other JSON library. Below is how you can parse it using Jackson's `ObjectMapper`.
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
public class JsonParser {
private static final ObjectMapper objectMapper = new ObjectMapper();
public static void parseStockQuote(String jsonResponse) throws IOException {
JsonNode rootNode = objectMapper.readTree(jsonResponse);
JsonNode lastNode = rootNode.path("last");
double price = lastNode.path("price").asDouble();
System.out.println("Stock Price: " + price);
}
}
- This code snippet reads the JSON response and prints out the stock price from the 'last' field.
Integrate and Test the Components
- Create a main method to fetch and parse the stock quote data. Ensure error handling for network issues, invalid API key, or JSON parsing errors.
public class Main {
public static void main(String[] args) {
PolygonApiFetcher apiFetcher = new PolygonApiFetcher();
try {
String response = apiFetcher.getStockQuote("AAPL");
if (response != null) {
JsonParser.parseStockQuote(response);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
- Run the program, specifying the stock ticker you're interested in, such as "AAPL" for Apple.
Concluding Remarks
- While the above code sets a foundation, remember that real-world applications require robust error handling.
- Consider caching responses if your application frequently requests the same data.
- Implement rate limiting if you expect high-volume requests to avoid rejecting by the API server.
