java - 为什么要在发送http请求之前使用Base64相关算法

Question

我正在做一些关于向 Teamcity 服务器发送 http REST 请求的事情。对于身份验证部分，当我使用下面的代码时，会出现 401 错误。

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());
        }
}

我通过添加以下代码解决了这个问题

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

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

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

但是，我不明白为什么这解决了我的问题。我的用户名或密码中没有任何特殊字符。并且，我在 Eclipse 中通过右键单击项目 --> 属性 --> 资源 --> 文本文件编码 --> UTF-8 将我的项目编码设置为 UTF-8。

getBytesUtf8方法的javadoc是

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

如果我的项目已经在使用 UTF-8，则此方法应该没有任何值(value)。

对于另一种方法encodeBase64，javadoc是:

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

也许有神奇的地方发生。我在 wiki 中读到了一些关于 Base64 的内容。

这个问题我说不清楚。那么谁能告诉我背后发生了什么。

Answer 1

这是在 RFC 7617 中定义的:

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 singlecolon (":") character, and the password,

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

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