Introduction

Have you ever come across a URL-encoded string and wondered how to convert it back to its original form? URL decoding is a common operation in web development and can be accomplished with ease using Java’s built-in libraries. In this tutorial, we’ll walk you through the process of URL decoding a string in Java.

Step 1: Import the Required Libraries

To begin, open your Java IDE and create a new Java class or open an existing one. Import the necessary library for URL decoding:

import java.net.URLDecoder;
import java.io.UnsupportedEncodingException;

Step 2: Call the URLDecoder.decode() Method

Next, we need to call the URLDecoder.decode() method to perform the URL decoding. This method requires the string to be decoded and the encoding format used for the URL encoding. In most cases, URLs are encoded using the UTF-8 encoding. Here’s an example:

String encodedString = ""Hello%20World%21"";
String decodedString = null;

try {
    decodedString = URLDecoder.decode(encodedString, ""UTF-8"");
} catch (UnsupportedEncodingException e) {
    e.printStackTrace();
}

In the code above, we have an encoded string ""Hello%20World%21"". The %20 represents a space character, and %21 represents an exclamation mark. We pass this encoded string along with the encoding format ""UTF-8"" to the URLDecoder.decode() method. The decoded string will be stored in the decodedString variable.

Step 3: Print the Decoded String

To visualize the URL decoding in action, let’s print the decoded string to the console:

System.out.println(""Decoded string: "" + decodedString);

Running the code will output the following:

Decoded string: Hello World!

As you can see, the URL-encoded string ""Hello%20World%21"" has been successfully decoded to ""Hello World!"".

Conclusion

URL decoding is a simple operation in Java thanks to the URLDecoder class. By following the steps outlined in this tutorial, you can easily decode URL-encoded strings and work with their original form. Incorporating URL decoding into your Java projects will enable you to handle and manipulate URLs and their encoded parameters effortlessly.

I hope you found this tutorial helpful! Happy coding!