Java - HttpURLConnection Class

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Java HttpURLConnection Class

java.net.HttpURLConnection, is an abstract class which represents the HTTP-specific URL connection. Instances of this class can be used both to read from and to write to the resource referenced by the URL.

For example −

• If you connect to a URL whose protocol is HTTP, the URL.openConnection() method returns an HttpURLConnection object.

Steps to make a connection to a URL

Following are the steps to make a connectiion to the URL and start processing.

• Invoke URL.openConnection() method to get HttpURLConnection object of an HTTP based URL.

• Update setup parameters and general request properties as required using connection object various setter methods.

• Create a connection to remote object using connect() method of connection object.

• Once remote object is available, access the content/headers of the remote object.

HttpURLConnection Class Declaration

public abstract class HttpURLConnection
   extends URLConnection

HttpURLConnection Class Fields

HttpURLConnection Class Methods

The HttpURLConnection class has many methods for setting or determining information about the connection, including the following −

Extends

This class extends following classes

• java.lang.Object

• java.net.URLConnection

Example of Java HttpURLConnection Class

The following HttpURLConnection program connects to a URL entered from the command line.

If the URL represents an HTTP resource, the connection is cast to HttpURLConnection, and the data in the resource is read one line at a time.

package com.tutorialspoint;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

public class HttpUrlConnectionDemo {
   public static void main(String [] args) {
      try {
         URL url = new URL("https://www.tutorialspoint.com");
         URLConnection urlConnection = url.openConnection();
         HttpURLConnection connection = null;
         if(urlConnection instanceof HttpURLConnection) {
            connection = (HttpURLConnection) urlConnection;
         }else {
            System.out.println("Please enter an HTTP URL.");
            return;
         }
         
         BufferedReader in = new BufferedReader(
            new InputStreamReader(connection.getInputStream()));
         String urlString = "";
         String current;
         
         while((current = in.readLine()) != null) {
            urlString += current;
         }
         System.out.println(urlString);
      } catch (IOException e) {
         e.printStackTrace();
      }
   }
}

A sample run of this program will produce the following result −

Output

$ java HttpURLConnection

.....a complete HTML content of home page of tutorialspoint.com.....