为什么我应该在发送http请求之前使用Base64相关算法

Question

I'm doing something about sending http REST request to Teamcity server. For the authentication part, when I use code below, I will get the 401 error.

public class Client {

    public static void main(String args[]){
        try{
            Client client = new Client();
            client.sendGet();
            //client.sendPost();
        }catch(Exception e){
            e.printStackTrace();
        }
    }

        String USER_AGENT = "";

        private void sendGet() throws Exception {

            String url = "http://localhost:80/httpAuth/app/rest/builds";

            URL obj = new URL(url);
            HttpURLConnection con = (HttpURLConnection) obj.openConnection();

            con.setRequestMethod("GET");

            con.setRequestProperty("User-Agent", USER_AGENT);

            String login = "gearon";
            String password = "gearonpassword";
            String token = login + ":" + password;

            con.setRequestProperty ("Authorization", "Basic " + token);

            int responseCode = con.getResponseCode();
            System.out.println("\nSending 'GET' request to URL : " + url);
            System.out.println("Response Code : " + responseCode);

            BufferedReader in = new BufferedReader(
                    new InputStreamReader(con.getInputStream()));
            String inputLine;
            StringBuffer response = new StringBuffer();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

            System.out.println(response.toString());
        }
}

I solve the problem by adding below code

    byte[] tokenArr = StringUtils.getBytesUtf8(token);

    String encoded = new String(Base64.encodeBase64(tokenArr));

    con.setRequestProperty ("Authorization", "Basic " + token); 

However, I can't figure out why this solved my problem. There is no any special character in my username or password. And, I have set my project encoding to UTF-8 in Eclipse by Right click the project --> Properties --> Resources --> Text file encoding --> UTF-8.

The javadoc of getBytesUtf8 method is

Encodes the given string into a sequence of bytes using the UTF-8 charset, storing the result into a new byte array.

If my project is using UTF-8 already, this method should add no value.

For another method encodeBase64 , the javadoc is:

Encodes binary data using the base64 algorithm but does not chunk the output.

Maybe there is where amazing happens. I read something about Base64 in wiki

I can't make myself clear about this issue. So could anybody tell me what happened behind.

Answer 1

This is defined in RFC 7617 :

To receive authorization, the client

1. obtains the user-id and password from the user,

2. constructs the user-pass by concatenating the user-id, a single colon (":") character, and the password,

3. encodes the user-pass into an octet sequence (see below for a discussion of character encoding schemes),

4. and obtains the basic-credentials by encoding this octet sequence using Base64 ([RFC4648], Section 4) into a sequence of US-ASCII characters ([RFC0020]).