HttpURLConnection is a powerful class in Java for making HTTP requests. It’s often used to interact with web APIs. This article explains how to retrieve the response body using HttpURLConnection.
Setting Up the Connection
First, set up and configure the HttpURLConnection object. Begin by creating a URL object:
URL url = new URL("http://example.com/api/resource");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
The URL points to the resource you want to access. The openConnection method opens the connection to the URL.
Handling the Response
Next, you need to get the response code to ensure the request was successful. Check if the response code is HTTP OK (200):
int responseCode = connection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String inputLine;
StringBuilder response = new StringBuilder();
while ((inputLine = in.readLine()) != null) {
response.append(inputLine);
}
in.close();
// Print the response
System.out.println("Response Body:");
System.out.println(response.toString());
} else {
System.out.println("GET request failed. Response Code: " + responseCode);
}
The code checks if the response code is 200 (HTTP OK). If true, it reads the response using a BufferedReader. The StringBuilder collects the response body line by line.
Exception Handling
Use a try-catch block to handle potential IOExceptions:
try {
// Set up and handle the connection and response here
} catch (IOException e) {
e.printStackTrace();
}
This ensures that any issues during the BTC Number connection or reading process are managed appropriately.
Using POST Requests
For POST requests, modify Australia Phone Number List the setup:
URL url = new URL("http://example.com/api/resource");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("POST");
connection.setDoOutput(true);
You also need to write the request body:
String jsonInputString = "{\"name\": \"John\", \"age\": 30}";
try (OutputStream os = connection.getOutputStream()) {
byte[] input = jsonInputString.getBytes("utf-8");
os.write(input, 0, input.length);
}
The rest of the code to handle the response remains the same as for a GET request.
Conclusion
HttpURLConnection is a versatile tool for making HTTP requests in Java. Setting up the connection and handling the response body is straightforward. This method ensures you can interact effectively with web APIs. With proper setup and error handling, you can manage GET and POST requests efficiently.
