OkHttpClient中添加digest auth

要在OkHttpClient中添加digest auth，你需要实现OkHttp的Authenticator接口，并将其设置到OkHttpClient中。具体的步骤如下：

1. 创建一个实现了Authenticator接口的类，例如DigestAuthenticator。

public class DigestAuthenticator implements Authenticator {
    private final String username;
    private final String password;
 
    public DigestAuthenticator(String username, String password) {
        this.username = username;
        this.password = password;
    }
 
    @Override
    public Request authenticate(Route route, Response response) throws IOException {
        String challenge = response.header("WWW-Authenticate");
        if (challenge == null || !challenge.startsWith("Digest ")) {
            // Challenge was not a digest authentication challenge.
            return null;
        }
 
        // Parse the challenge parameters.
        Map<String, String> params = parseChallengeParameters(challenge.substring("Digest ".length()));
 
        // Compute the response value.
        String uri = response.request().url().toString();
        String realm = params.get("realm");
        String nonce = params.get("nonce");
        String qop = params.get("qop");
        String nc = "00000001";
        String cnonce = "0a4f113b";
        String method = response.request().method();
        String ha1 = md5(username + ":" + realm + ":" + password);
        String ha2 = md5(method + ":" + uri);
        String responseValue = md5(ha1 + ":" + nonce + ":" + nc + ":" + cnonce + ":" + qop + ":" + ha2);
 
        // Build the authentication header.
        String headerValue = "Digest "
                + "username=\"" + username + "\", "
                + "realm=\"" + realm + "\", "
                + "nonce=\"" + nonce + "\", "
                + "uri=\"" + uri + "\", "
                + "qop=" + qop + ", "
                + "nc=" + nc + ", "
                + "cnonce=\"" + cnonce + "\", "
                + "response=\"" + responseValue + "\", "
                + "opaque=\"" + params.get("opaque") + "\"";
 
        // Return the authenticated request.
        return response.request().newBuilder()
                .header("Authorization", headerValue)
                .build();
    }
 
    private Map<String, String> parseChallengeParameters(String challenge) {
        // Parse the challenge parameters.
        Map<String, String> params = new HashMap<>();
        for (String param : challenge.split(",\\s*")) {
            int equalsIndex = param.indexOf('=');
            if (equalsIndex != -1) {
                String key = param.substring(0, equalsIndex).trim();
                String value = param.substring(equalsIndex + 1).trim();
                if (value.startsWith("\"") && value.endsWith("\"")) {
                    value = value.substring(1, value.length() - 1);
                }
                params.put(key, value);
            }
        }
        return params;
    }
 
    private static String md5(String s) {
        try {
            MessageDigest digest = MessageDigest.getInstance("MD5");
            byte[] bytes = digest.digest(s.getBytes("UTF-8"));
            return ByteString.of(bytes).hex();
        } catch (NoSuchAlgorithmException | UnsupportedEncodingException e) {
            throw new AssertionError(e);
        }
    }
}

上述代码中的md5方法是用来计算MD5值的，使用了OkHttp中的ByteString类。

2. 创建一个OkHttpClient对象，并将DigestAuthenticator设置为它的Authenticator。

OkHttpClient client = new OkHttpClient.Builder()
        .authenticator(new DigestAuthenticator("username", "password"))
        .build();

在创建OkHttpClient对象时，使用Builder模式设置了Authenticator，将DigestAuthenticator对象作为参数传递给它。

3. 使用OkHttpClient对象来发送请求。

Request request = new Request.Builder()
        .url("http://example.com")
        .build();

Response response = client.newCall(request).execute();

在发送请求时，使用了OkHttpClient对象来发送请求。如果服务器需要digest auth认证，OkHttpClient会自动使用设置的Authenticator进行认证。