问题
I'm trying to use Digest authentication with HTTP Client against a 3rd-party web service that I don't control.
I started out with the sample code from here:
http://hc.apache.org/httpcomponents-client-4.5.x/httpclient/examples/org/apache/http/examples/client/ClientPreemptiveDigestAuthentication.java 
I got it working against httpbin.org, before attempting the next step described below.
It appears that the target 3rd-party service that I'm using requires the opaque value to be copied from the WWW-Authentication header on the initial response to the Authorization header on the next request, as described here:
https://security.stackexchange.com/questions/24425/what-is-the-opaque-field-in-http-digest-access-authentication-used-for
However, I have turned on wire-logging and stepped through the code (again this is really just the sample code linked above, no need to copy/paste it here) and I see that the opaque is NOT copied.
Any ideas what prevents it from being copied?
I even tried overriding the processChallenge method:
    DigestScheme digestAuth = new DigestScheme() {
        @Override
        public void processChallenge(
                Header header) throws MalformedChallengeException {
but it appears that any value introduced into the Parameters at this point is ignored in the next request.
回答1:
Finally fixed by overriding the Authorize header explicitly, instead of relying on the internals of HttpClient to do it automatically:
package [...];
import java.util.Arrays;
import java.util.Map;
import java.util.stream.Collectors;
import org.apache.commons.io.IOUtils;
import org.apache.http.*;
import org.apache.http.auth.AuthScope;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.client.*;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.impl.auth.DigestScheme;
import org.apache.http.impl.client.*;
import org.testng.Assert;
public class DigestTest {
    private static final String URL
            = "https://...";
    private static final String PASSWORD = ...;
    private static final String USER = ...;
    public static void main(String[] args) throws Exception {
        new DigestTest().run();
    }
    public void run() throws Exception {
        HttpGet httpget = new HttpGet(URL);
        HttpHost target
                = new HttpHost(httpget.getURI().getHost(), 443, "https");
        CredentialsProvider credsProvider = new BasicCredentialsProvider();
        UsernamePasswordCredentials credentials
                = new UsernamePasswordCredentials(USER, PASSWORD);
        credsProvider.setCredentials(
                new AuthScope(target.getHostName(), target.getPort()),
                credentials);
        CookieStore cookieStore = new BasicCookieStore();
        CloseableHttpClient httpclient
                = HttpClients.custom().setDefaultCookieStore(cookieStore)
                        .setDefaultCredentialsProvider(credsProvider).build();
        try {
            DigestScheme digestAuth = new DigestScheme();
            digestAuth.overrideParamter("qop", "auth");
            digestAuth.overrideParamter("nc", "0");
            digestAuth.overrideParamter("cnonce", DigestScheme.createCnonce());
            AuthCache authCache = new BasicAuthCache();
            authCache.put(target, digestAuth);
            HttpClientContext localContext = HttpClientContext.create();
            localContext.setAuthCache(authCache);
            CloseableHttpResponse response;
            response = httpclient.execute(target, httpget, localContext);
            Map<String, String> wwwAuth = Arrays
                    .stream(response.getHeaders("WWW-Authenticate")[0]
                            .getElements())
                    .collect(Collectors.toMap(HeaderElement::getName,
                            HeaderElement::getValue));
            // the first call ALWAYS fails with a 401
            Assert.assertEquals(response.getStatusLine().getStatusCode(), 401);
            digestAuth.overrideParamter("opaque", wwwAuth.get("opaque"));
            digestAuth.overrideParamter("nonce", wwwAuth.get("nonce"));
            digestAuth.overrideParamter("realm", wwwAuth.get("Digest realm"));
            Header authenticate = digestAuth.authenticate(credentials, httpget,
                    localContext);
            httpget.addHeader(authenticate);
            response = httpclient.execute(target, httpget, localContext);
            // the 2nd call is the real deal
            Assert.assertEquals(response.getStatusLine().getStatusCode(), 200);
            System.out.println(IOUtils
                    .toString(response.getEntity().getContent(), "utf-8"));
        } finally {
            httpclient.close();
        }
    }
}
    来源:https://stackoverflow.com/questions/53028003/apache-httpclient-digestauth-doesnt-forward-opaque-value-from-challenge