Java URL Class

A URL (Uniform Resource Locator) is the address used to locate resources on the Internet. In Java, the URL class provides a simple way to work with web addresses and access their components such as protocol, host, port, and file path. In this chapter, you will learn about the URL class, its constructors, methods, and example.

What is URL Class in Java?

The URL class is a part of the java.net package and is used to represent a Uniform Resource Locator (URL). A URL points to a resource available on the Internet.

For example:

Using the URL class, you can extract different parts of a URL, such as:

• Protocol: Defines the communication method (e.g., http, https, ftp)
• Host Name (Server Name): The domain name or IP address (e.g., www.tpointtech.com)
• Port Number: Optional value; if not specified, it returns -1. For example, if we write http//ww.tpointtech.com:80/sonoojaiswal/ , 80 is the port number.
• File Name / Path: The specific resource (e.g., index.jsp)

Example Breakdown of a URL

For the URL:

• Protocol: http
• Host: www.tpointtech.com
• Port: 80
• File: index.jsp

If the port number is not mentioned, Java automatically returns -1.

Java URL Class Constructors

This class has the following constructors:

1. URL(String spec)

Creates an instance of a URL from the String representation.

Here is the syntax:

2. URL(String protocol, String host, int port, String file)

Creates an instance of a URL from the given protocol, host, port number, and file.

Here is the syntax:

3. URL(String protocol, String host, int port, String file, URLStreamHandler handler)

Creates an instance of a URL from the given protocol, host, port number, file, and handler.

Here is the syntax:

4. URL(String protocol, String host, String file)

Creates an instance of a URL from the given protocol name, host name, and file name.

Here is the syntax:

5. URL(URL context, String spec)

Creates an instance of a URL by parsing the given spec within a specified context.

Here is the syntax:

6. URL(URL context, String spec, URLStreamHandler handler)

Creates an instance of a URL by parsing the given spec with the specified handler within a given context.

Here is the syntax:

URL Class Methods

The java.net.URL class provides many methods. The most important methods of the URL class are given below.

Examples of URL Class

The following examples demonstrate how to use the URL class to extract different parts of a URL.

Example 1: Extract Basic URL Information

In the following example, we create a URL object and retrieve its protocol, host name, port number, and file name.

Output:

Protocol: http
Host Name: www.tpointtech.com
Port Number: -1
File Name: /java-tutorial

Example 2: Extract Detailed URL Information

In the following example, we extract additional details such as default port, query string, path, and file from a URL.

Output:

Protocol: https
Host Name: www.google.com
Port Number: -1
Default Port Number: 443
Query String: q=tpointtech&oq=tpointtech&sourceid=chrome&ie=UTF-8
Path: /search
File: /search?q=tpointtech&oq=tpointtech&sourceid=chrome&ie=UTF-8