Java Get Data From URL

We can access data from a specific URL using a Java program. Java provides URL and URLConnection classes to communicate with the URL over a network. These classes have several useful methods to deal with HTTP URLs.

In this section, we will discuss how to access data from a specific URL using a Java program.

Let's discuss URL and URLConnection classes:

URL Class

The URL class represents a URL (Uniform Resource Locator), a pointer to web content on the WWW (World Wide Web). Web content can be an ordinary file or directory, query to database, reference to an object, etc.

An example of the URL as follows:

https://www.javatpoint.com/java-tutorial

The URL class displays the following information of the URL:

Protocol: A protocol defines the set of rules for communication. In the above URL, the https is a protocol.

Server name or IP Address: Server name or domain name or IP address is the particular address of a Host. In the above example, www.javatpoint.com is the server name.

Port Number: The port number is an optional attribute.

File Name or directory name: The filename is the name of the particular file of your project. In the above example, java-tutorial is the file name.

Consider the below example of Java URL class:

URLExample.java:

package com.javatpoint;
import java.net.*; 
public class URLExample { 
	public static void main(String[] args){  
	try{  
	URL url=new URL("https://www.javatpoint.com/java-tutorial");  
	System.out.println("Protocol: "+url.getProtocol());// Using getProtocol() method of the URL class
	System.out.println("Host Name: "+url.getHost()); // Using getHost() method 
	System.out.println("Port Number: "+url.getPort());  // Using getPort() method
	System.out.println("File Name: "+url.getFile());    //Using getFile() method
	}
	catch(Exception e)
	{
		System.out.println(e);}  
	}  
	}

Output:

Protocol: https
Host Name: www.javatpoint.com
Port Number: -1
File Name: /java-tutorial

URLConnection Class

The URLConnection class specifies a between the URL and our application. This class has methods to read and write data to the specified resource referred by the URL.

The openConnection() method is used to get the object of URLConnection class. It's syntax is as follows:

Read more about the Java URLConnection class.

Let's understand how to get data from URL.

How to Access Data From a URL Using Java

We have discussed the URL and URLConnection Class; now, it is easy to understand how to get data from a given URL. Here, we will access the data using these classes. We will use the combination of InputStreamReader and BufferedReader to read the data from a specified URL. We should follow the below steps to create a Java program for this process:

Create a URLConnectionReader class
Now, create a new URL object and pass the desired URL that we want to access.
Now, using this url object, create a URLConnection object.
Use the InputStreamReader and BufferedReader to read from the URL connection.
The readLine method of BufferedReader returns a String that we can access. If this string is null, it means we have reached the end of the document.
Now, Append the string series that we have received as output from the URL to your StringBuilder object.

Let's implement the above steps using Java code:

Consider the below example:

UrlConnectionReader.java:

package com.javatpoint;
import java.net.*;
import java.io.*;
public class UrlConnectionReader
{
  public static void main(String[] args)
  {
    String output  = getUrlContents("https://www.javatpoint.com/java-tutorial");
    System.out.println(output);
  }

  private static String getUrlContents(String theUrl)
  {
    StringBuilder content = new StringBuilder();
  // Use try and catch to avoid the exceptions
    try
    {
      URL url = new URL(theUrl); // creating a url object
      URLConnection urlConnection = url.openConnection(); // creating a urlconnection object

      // wrapping the urlconnection in a bufferedreader
      BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
      String line;
      // reading from the urlconnection using the bufferedreader
      while ((line = bufferedReader.readLine()) != null)
      {
        content.append(line + "\n");
      }
      bufferedReader.close();
    }
    catch(Exception e)
    {
      e.printStackTrace();
    }
    return content.toString();
  }
}

Output: