Base64Encoder cannot be resolved

This is my Java code in a JSP file. I am getting

Base64Encoder cannot be resolved.

Why is it so? I have to add something related to Base64Encoder. Any suggestions will be appreciated.

    <%@ page language="java" import="java.io.OutputStream,java.net.HttpURLConnection,java.net.URL,java.util.Collection,org.apache.commons.httpclient.Credentials,org.apache.commons.httpclient.auth.AuthenticationException,org.apache.commons.httpclient.auth.MalformedChallengeException,org.apache.commons.httpclient.params.DefaultHttpParams,org.apache.commons.httpclient.params.HttpParams,org.apache.commons.httpclient.auth.AuthScheme,org.apache.commons.httpclient.auth.AuthPolicy,org.apache.commons.httpclient.HttpClient,org.apache.commons.httpclient.UsernamePasswordCredentials,org.apache.commons.httpclient.auth.AuthScope,org.apache.commons.httpclient.methods.GetMethod,org.w3c.dom.*,javax.xml.parsers.DocumentBuilder,javax.xml.parsers.DocumentBuilderFactory,java.net.*,java.io.*" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>

<%
String a_Url = request.getParameter( "url" ) ;

URL url = new URL (a_Url);
String encoding = Base64Encoder.encode ("test:test");

HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setDoOutput(true);
connection.setRequestProperty  ("Authorization", "Basic " + encoding);
InputStream content = (InputStream)connection.getInputStream();
BufferedReader in   = 
    new BufferedReader (new InputStreamReader (content));
String line;
while ((line = in.readLine()) != null) {
    System.out.println(line);
}

%>