自定义Spring AuthenticationFailureHandler不重定向

Question

我的配置中有这个bean定义：

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-53-6c1545864b12> in <module>()
      6 
      7 kmeans = KMeans()
----> 8 kmeans.fit(df)

~/anaconda3/envs/pds/lib/python3.6/site-packages/dask_ml/cluster/k_means.py in fit(self, X, y)
    187 
    188     def fit(self, X, y=None):
--> 189         X = self._check_array(X)
    190         labels, centroids, inertia, n_iter = k_means(
    191             X,

~/anaconda3/envs/pds/lib/python3.6/site-packages/dask_ml/utils.py in wraps(*args, **kwargs)
    298         def wraps(*args, **kwargs):
    299             with _timer(f.__name__, _logger=logger, level=level):
--> 300                 results = f(*args, **kwargs)
    301             return results
    302 

~/anaconda3/envs/pds/lib/python3.6/site-packages/dask_ml/cluster/k_means.py in _check_array(self, X)
    159         elif isinstance(X, dd.DataFrame):
    160             raise TypeError(
--> 161                 "Cannot fit on dask.dataframe due to unknown " "partition lengths."
    162             )
    163 

TypeError: Cannot fit on dask.dataframe due to unknown partition lengths.

还有我的context.xml：

public class MyAuthenticationFailureHandler extends SimpleUrlAuthenticationFailureHandler {

private String defaultFailureUrl;

public String getDefaultFailureUrl() {
    return defaultFailureUrl;
}

public void setDefaultFailureUrl(String defaultFailureUrl) {
    this.defaultFailureUrl = defaultFailureUrl;
}

@Override
public void onAuthenticationFailure (HttpServletRequest request, HttpServletResponse response,
        AuthenticationException exception) throws IOException, ServletException  {

    //  do logging and login failure counts etc...
    logger.debug("Sending redirect to:"+defaultFailureUrl);
    response.sendRedirect(defaultFailureUrl);
}

在日志中，我得到“发送重定向到：空”

为什么将defaultFailureUrl设置为null？我在上下文中设置属性值。我在这里做什么错了？