I've been experimenting with various bits of Java code trying to come up with something that will encode a string containing quotes, spaces and exotic Unicode characters and produce output that's identical to JavaScript's encodeURIComponent function.

My torture test string is: A B ±

If I enter the following JavaScript statement in Firebug:

encodeURIComponent('A B ± ');

—Then I get:

%22A%22%20B%20%C2%B1%20%22

Here's my little test Java program:

import java.io.UnsupportedEncodingException;

import java.net.URLEncoder;



public class EncodingTest

{

  public static void main(String[] args) throws UnsupportedEncodingException

  {

    String s = A B ± ;

    System.out.println(URLEncoder.encode returns 

      + URLEncoder.encode(s, UTF-8));



    System.out.println(getBytes returns 

      + new String(s.getBytes(UTF-8), ISO-8859-1));

  }

}

—This program outputs:

URLEncoder.encode returns %22A%22+B+%C2%B1+%22

getBytes returns A B ± 

Close, but no cigar! What is the best way of encoding a UTF-8 string using Java so that it produces the same output as JavaScript's encodeURIComponent?

EDIT: I'm using Java 1.4 moving to Java 5 shortly.