Sending HTTP Request in Java

In this article, we will show you how to send HTTP Request using GET & POST method using Java API’s.

• javax.net.ssl.HttpsURLConnection
• java.net.HttpURLConnection

1. Java – HttpURLConnection

HttpURLConnection is available in Java base API. Below are the few pros & cons.

• Pros
  • No need to add any extra library in your code
• Cons
  • Very old API & outdated
  • Very difficult to configure and use this class
  • May not support HTTP/2 standards
  • Not recommended to use

The below example is for self reference however, note that usage of this class and recommended.

package com.techgig365.http;

import javax.net.ssl.HttpsURLConnection;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpURLConnectionExample {

    public static void main(String[] args) throws Exception {

        HttpURLConnectionExample obj = new HttpURLConnectionExample();

        System.out.println("Test 1 - Send Http GET request");
        obj.sendGetRequest();

        System.out.println("Test 2 - Send Http POST request");
        obj.sendPostRequest();

    }

    private void sendGetRequest() throws Exception {

        String url = "https://www.google.com/search?q=techgig365.wordpress.com";

        HttpURLConnection httpClient =
                (HttpURLConnection) new URL(url).openConnection();

        // Optional default is GET
        httpClient.setRequestMethod("GET");

        // Add request header
        httpClient.setRequestProperty("User-Agent", "Mozilla/5.0");

        int responseCode = httpClient.getResponseCode();
        System.out.println("\nSending 'GET' request to URL : " + url);
        System.out.println("Response Code : " + responseCode);

        try (BufferedReader in = new BufferedReader(
                new InputStreamReader(httpClient.getInputStream()))) {

            StringBuilder response = new StringBuilder();
            String line;

            while ((line = in.readLine()) != null) {
                response.append(line);
            }

            // Show result
            System.out.println(response.toString());

        }

    }

    private void sendPostRequest() throws Exception {

        String url = "https://httpbin.org/post";

        HttpsURLConnection httpClient = (HttpsURLConnection) new URL(url).openConnection();

        // Add request header
        httpClient.setRequestMethod("POST");
        httpClient.setRequestProperty("User-Agent", "Mozilla/5.0");
        httpClient.setRequestProperty("Accept-Language", "en-US,en;q=0.5");

        String urlParameters = "sn=C02G8416DRJM&cn=&locale=&caller=&num=12345";

        // Send post request
        httpClient.setDoOutput(true);
        try (DataOutputStream wr = new DataOutputStream(httpClient.getOutputStream())) {
            wr.writeBytes(urlParameters);
            wr.flush();
        }

        int responseCode = httpClient.getResponseCode();
        System.out.println("\nSending 'POST' request to URL : " + url);
        System.out.println("Post parameters : " + urlParameters);
        System.out.println("Response Code : " + responseCode);

        try (BufferedReader in = new BufferedReader(
                new InputStreamReader(httpClient.getInputStream()))) {

            String line;
            StringBuilder response = new StringBuilder();

            while ((line = in.readLine()) != null) {
                response.append(line);
            }

            // Show result
            System.out.println(response.toString());

        }

    }

}