URL and URLConnection classes

The URL and URLConnection classes are part of Java's standard library and are used for working with URLs (Uniform Resource Locators) and accessing resources on the Internet.

URL Class: The URL class is used to represent a URL. It has several methods for parsing a URL string and obtaining information about the URL, such as the protocol, host, port, file path, etc. The URL class can be used to connect to a URL and retrieve the contents of a web page, for example.

Example:

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

public class URLDemo {
    public static void main(String[] args) throws IOException {
        URL url = new URL("https://www.example.com");
        BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        reader.close();
    }
}

URLConnection Class: The URLConnection class is a subclass of URL and provides more advanced functionality for connecting to a URL and sending and receiving data. It is used to establish a connection to a URL and perform I/O operations, such as sending and retrieving data.

Example:

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

public class URLConnectionDemo {
    public static void main(String[] args) throws IOException {
        URL url = new URL("https://www.example.com");
        URLConnection connection = url.openConnection();
        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
        reader.close();
    }
}

In both examples, the URL and URLConnection classes are used to retrieve the contents of a web page from a URL and print it to the console. The URL class is simpler and provides a convenient way to connect to a URL, while the URLConnection class provides more advanced functionality for working with URLs and performing I/O operations.