import org.apache.commons.httpclient.auth.CredentialsNotAvailableException; //导入依赖的package包/类
public Credentials getCredentials(AuthScheme scheme, String host, int port, boolean proxy)
        throws CredentialsNotAvailableException {

    if (Constants.SCHEME.equals(scheme.getSchemeName())) {
        if (signer == null) {
            throw new CredentialsNotAvailableException("SSHKey Signer not available");
        } else {
            return new SignerCredentials(signer);
        }
    } else {
        if (this.delegatee != null) {
            return this.delegatee.getCredentials(scheme, host, port, proxy);
        }
    }
    return null;
}
 

import org.apache.commons.httpclient.auth.CredentialsNotAvailableException; //导入依赖的package包/类
private Credentials promptForCredentials(
    final AuthScheme authScheme,
    final HttpParams params, 
    final AuthScope authscope)
{
    LOG.debug("Credentials required");
    Credentials creds = null;
    CredentialsProvider credProvider = 
        (CredentialsProvider)params.getParameter(CredentialsProvider.PROVIDER);
    if (credProvider != null) {
        try {
            creds = credProvider.getCredentials(
                authScheme, authscope.getHost(), authscope.getPort(), false);
        } catch (CredentialsNotAvailableException e) {
            LOG.warn(e.getMessage());
        }
        if (creds != null) {
            this.state.setCredentials(authscope, creds);
            if (LOG.isDebugEnabled()) {
                LOG.debug(authscope + " new credentials given");
            }
        }
    } else {
        LOG.debug("Credentials provider not available");
    }
    return creds;
}
 

import org.apache.commons.httpclient.auth.CredentialsNotAvailableException; //导入依赖的package包/类
private Credentials promptForProxyCredentials(
    final AuthScheme authScheme,
    final HttpParams params,
    final AuthScope authscope) 
{
    LOG.debug("Proxy credentials required");
    Credentials creds = null;
    CredentialsProvider credProvider = 
        (CredentialsProvider)params.getParameter(CredentialsProvider.PROVIDER);
    if (credProvider != null) {
        try {
            creds = credProvider.getCredentials(
                authScheme, authscope.getHost(), authscope.getPort(), true);
        } catch (CredentialsNotAvailableException e) {
            LOG.warn(e.getMessage());
        }
        if (creds != null) {
            this.state.setProxyCredentials(authscope, creds);
            if (LOG.isDebugEnabled()) {
                LOG.debug(authscope + " new credentials given");
            }
        }
    } else {
        LOG.debug("Proxy credentials provider not available");
    }
    return creds;
}
 

import org.apache.commons.httpclient.auth.CredentialsNotAvailableException; //导入依赖的package包/类
public Credentials getCredentials(AuthScheme scheme, String host, int port, boolean proxy)
        throws CredentialsNotAvailableException {
    if (!proxy) {
        this.hostcount++;
        return provideCredentials(this.hostcount);
    } else {
        this.proxycount++;
        return provideCredentials(this.proxycount);
    }
}
 

import org.apache.commons.httpclient.auth.CredentialsNotAvailableException; //导入依赖的package包/类
/**
 * Produces Negotiate authorization string based on token created by 
 * processChallenge.
 * 
 * @param credentials Never used be the Negotiate scheme but must be provided to 
 * satisfy common-httpclient API. Credentials from JAAS will be used insted.
 * @param method The method being authenticated
 * 
 * @throws AuthenticationException if authorization string cannot 
 *   be generated due to an authentication failure
 * 
 * @return an Negotiate authorization string
 * 
 * @since 3.0
 */
public String authenticate(
    Credentials credentials, 
    HttpMethod method
) throws AuthenticationException {
    LOG.debug("enter NegotiateScheme.authenticate(Credentials, HttpMethod)");

    if (state == UNINITIATED) {
        throw new IllegalStateException(
           "Negotiation authentication process has not been initiated");
    }

    try {
        try {                
            if(context==null) {
                LOG.info("host: " + method.getURI().getHost());
                init( method.getURI().getHost() );
            }
        } catch (org.apache.commons.httpclient.URIException urie) {
            LOG.error(urie.getMessage());
            state = FAILED;
            throw new AuthenticationException(urie.getMessage());
        }
    
        // HTTP 1.1 issue:
        // Mutual auth will never complete do to 200 insted of 401 in 
        // return from server. "state" will never reach ESTABLISHED
        // but it works anyway
        token = context.initSecContext(token, 0, token.length);
        LOG.info("got token, sending " + token.length + " to server");
    } catch (GSSException gsse) {
        LOG.fatal(gsse.getMessage());
        state = FAILED;
        if( gsse.getMajor() == GSSException.DEFECTIVE_CREDENTIAL
                || gsse.getMajor() == GSSException.CREDENTIALS_EXPIRED )
            throw new InvalidCredentialsException(gsse.getMessage(),gsse);
        if( gsse.getMajor() == GSSException.NO_CRED )
            throw new CredentialsNotAvailableException(gsse.getMessage(),gsse);
        if( gsse.getMajor() == GSSException.DEFECTIVE_TOKEN
                || gsse.getMajor() == GSSException.DUPLICATE_TOKEN
                || gsse.getMajor() == GSSException.OLD_TOKEN )
            throw new AuthChallengeException(gsse.getMessage(),gsse);
        // other error
        throw new AuthenticationException(gsse.getMessage());
    }
    return "Negotiate " + new String(new Base64().encode(token));
}