java.net.URLEncoder Example

Ashraf SarhanSeptember 24th, 2014Last Updated: September 24th, 2014

0 486 1 minute read

In this example we shall show you how to make use of URLEncoder class. URLEncoder is a utility class for HTML form encoding, contains static methods for converting a string to the application/x-www-form-urlencoded MIME format. This class is very useful to encode URL query string values.

When encoding a string, the following rules apply:

The alphanumeric characters “a” through “z”, “A” through “Z” and “0” through “9” remain the same.
The special characters “.”, “-“, “*”, and “_” remain the same.
The space character ” ” is converted into a plus sign “+”.
All other characters are unsafe and are first converted into one or more bytes using some encoding scheme. Then each byte is represented by the 3-character string “%xy”, where xy is the two-digit hexadecimal representation of the byte.

Below example shows how to encode URL content in java using URLEncoder.

Example:

URLEncoderTest.java

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

/**
 * @author ashraf_sarhan
 * 
 */
public class URLEncoderTest {

	
	/**
	 * The main method.
	 *
	 * @param args the arguments
	 */
	public static void main(String[] args) {
		try {

			String string = "The string ü@foo-bar";

			String encodedString = URLEncoder.encode(string, "UTF-8");

			System.out.println("Encoded String: " + encodedString);

		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
	}

}

In the above example using UTF-8 as the encoding scheme, the string “The string ü@foo-bar” would get converted to “The+string+%C3%BC%40foo-bar” because in UTF-8 the character ü is encoded as two bytes C3 (hex) and BC (hex), and the character @ is encoded as one byte 40 (hex).

Tip

Method encode(String s) has been deprecated with encode(String s, String enc) now being the only available method.
The recommended encoding scheme to use is UTF-8. However, for compatibility reasons, if an encoding is not specified, then the default encoding of the platform is used.

3. Download the Source Code of this example:

This was an example of how to use URLEncoder class.

Download
You can download the full source code of this example here: java.net.URLEncoder Example Code