Returns an account's authentication-specific information for the specified <tt>token</tt>,
or <tt>null</tt> if no account could be found based on the <tt>token</tt>.
<p>This method effectively represents a login attempt for the corresponding user with the underlying EIS datasource.
Most implementations merely just need to lookup and return the account data only (as the method name implies)
and let Shiro do the rest, but implementations may of course perform eis specific login operations if so
desired.
@param token the application-specific representation of an account principal and credentials.
@return the authentication information for the account associated with the specified <tt>token</tt>,
or <tt>null</tt> if no account could be found.
@throws hunt.shiro.authc.AuthenticationException
if there is an error obtaining or constructing an AuthenticationInfo object based on the
specified <tt>token</tt> or implementation-specific login behavior fails.
Returns an account's authentication-specific information for the specified <tt>token</tt>, or <tt>null</tt> if no account could be found based on the <tt>token</tt>.
<p>This method effectively represents a login attempt for the corresponding user with the underlying EIS datasource. Most implementations merely just need to lookup and return the account data only (as the method name implies) and let Shiro do the rest, but implementations may of course perform eis specific login operations if so desired.
@param token the application-specific representation of an account principal and credentials. @return the authentication information for the account associated with the specified <tt>token</tt>, or <tt>null</tt> if no account could be found. @throws hunt.shiro.authc.AuthenticationException if there is an error obtaining or constructing an AuthenticationInfo object based on the specified <tt>token</tt> or implementation-specific login behavior fails.