import org.apache.http.impl.client.SystemDefaultCredentialsProvider; //导入依赖的package包/类
private HttpContext createContextForServer(ServerInfo serverInfo)
{
	HttpContext httpContext = null;
	if (serverInfo.credentials != null || serverInfo.ntCredentials != null)
	{
		HttpClientContext context = HttpClientContext.create();
		CredentialsProvider credsProvider = (useBuiltinWindowsAuthentication(serverInfo)) ? credsProvider = new WindowsCredentialsProvider(new SystemDefaultCredentialsProvider()) : 
			                                                                                                  new HttpClientCredentialsProvider(serverInfo.credentials, serverInfo.ntCredentials);
		if (serverInfo.credentials != null)
		{
			credsProvider.setCredentials(serverInfo.authscope, serverInfo.credentials);
		}
		if (serverInfo.ntCredentials != null)
		{
			credsProvider.setCredentials(serverInfo.authscope, serverInfo.ntCredentials);
		}
		context.setCredentialsProvider(credsProvider);
		httpContext = context;
	}
	return httpContext;
}
 

import org.apache.http.impl.client.SystemDefaultCredentialsProvider; //导入依赖的package包/类
public void configure(HttpClientBuilder builder) {
    SystemDefaultCredentialsProvider credentialsProvider = new SystemDefaultCredentialsProvider();
    configureSslSocketConnectionFactory(builder, httpSettings.getSslContextFactory());
    configureAuthSchemeRegistry(builder);
    configureCredentials(builder, credentialsProvider, httpSettings.getAuthenticationSettings());
    configureProxy(builder, credentialsProvider, httpSettings);
    configureUserAgent(builder);
    builder.setDefaultCredentialsProvider(credentialsProvider);
}
 

import org.apache.http.impl.client.SystemDefaultCredentialsProvider; //导入依赖的package包/类
@Test(timeout=30000) // this timeout (in ms) needs to be extended if you're actively debugging the code
public void testNoInfiniteLoopOnSPNOutsideDomain() throws Exception {
    Assume.assumeTrue("Test can only be run on Windows", WinHttpClients.isWinAuthAvailable());

    // HTTPCLIENT-1545
    // If a service principal name (SPN) from outside your Windows domain tree (e.g., HTTP/example.com) is used,
    // InitializeSecurityContext will return SEC_E_DOWNGRADE_DETECTED (decimal: -2146892976, hex: 0x80090350).
    // Because WindowsNegotiateScheme wasn't setting the completed state correctly when authentication fails,
    // HttpClient goes into an infinite loop, constantly retrying the negotiate authentication to kingdom
    // come. This error message, "The system detected a possible attempt to compromise security. Please ensure that
    // you can contact the server that authenticated you." is associated with SEC_E_DOWNGRADE_DETECTED.

    final Registry<AuthSchemeProvider> authSchemeRegistry = RegistryBuilder.<AuthSchemeProvider>create()
        .register(AuthSchemes.SPNEGO, new AuthSchemeProvider() {
            @Override
            public AuthScheme create(final HttpContext context) {
                return new WindowsNegotiateSchemeGetTokenFail(AuthSchemes.SPNEGO, "HTTP/example.com");
            }
        }).build();
    final CredentialsProvider credsProvider =
            new WindowsCredentialsProvider(new SystemDefaultCredentialsProvider());
    final CloseableHttpClient customClient = HttpClientBuilder.create()
            .setDefaultCredentialsProvider(credsProvider)
            .setDefaultAuthSchemeRegistry(authSchemeRegistry).build();

    final HttpHost target = start();
    final HttpGet httpGet = new HttpGet("/");
    final CloseableHttpResponse response = customClient.execute(target, httpGet);
    try {
        EntityUtils.consume(response.getEntity());
    } finally {
        response.close();
    }
}
 

import org.apache.http.impl.client.SystemDefaultCredentialsProvider; //导入依赖的package包/类
private static HttpClientContext internalCreateSSOContext() {
  
  if (log.isDebugEnabled()) log.debug("internalCreateSSOContext(");

  //System.setProperty("java.security.krb5.conf", "C:\\Windows\\krb5.ini");
  //System.setProperty("sun.security.krb5.debug", "true");
  System.setProperty("javax.security.auth.useSubjectCredsOnly","false");

  HttpClientContext context = HttpClientContext.create();
  
  if (isNTLMAuthenticationEnabled()) {
    if (log.isDebugEnabled()) log.debug("set WindowsCredentialsProvider");
    final CredentialsProvider credsProvider = new WindowsCredentialsProvider(new SystemDefaultCredentialsProvider());
    context.setCredentialsProvider(credsProvider);
  }
  else {

    if (log.isDebugEnabled()) log.debug("set JAAS credential provider");

    // This may seem odd, but specifying 'null' as principal tells java to use the logged in user's credentials
    Credentials useJaasCreds = new Credentials() {
      public String getPassword() { return null; }
      public Principal getUserPrincipal() { return null; }
    };

    BasicCredentialsProvider credentialsProvider = new BasicCredentialsProvider();
    credentialsProvider.setCredentials( new AuthScope(null, -1, null), useJaasCreds );
    context.setCredentialsProvider(credentialsProvider);
  }
  
  if (log.isDebugEnabled()) log.debug(")internalCreateSSOContext");
  return context;
}