Question

I am using a customized UserDetailsService for my Spring security settings.
The customized UserDetailsService has only one method which overrides loadUserByUsername(final String username) in UserDetailsService.

I’ve below configuration in applicationConext-security.xml:

<authentication-manager alias="myAuthenticationManager">
      <authentication-provider user-service-ref="userDetailsService"/>
</authentication-manager>

<beans:bean id="userDetailsService"
    class="temp.com.JpaUserDetailsService" />

However when I tried to login using a username I get the error saying the arguement “username” is null. I wonder where does username come from and how can I avoid it to be null?

Answer 1

There are several possibilities for this, and since you haven’t posted any stack trace, it’s unclear if the problem is in your code, or configuration:

• You have configured the filter chain explicitly, and are either missing filters or have the standard filters in the wrong order.
  • Suggestion: Replace your custom filter chain (temporarily) with the default one and make sure it works.
• You have a bug in your custom UserDetailsService
  • Suggestion: Use a debugger to verify what username you are being passed).
• Your login form (assuming you are using form-based authentication) is not set up with the correct username/password fields
  • Suggestion: j_username and j_password are the standard field names (unless you have customized them). If you’re using JSF, GWT, or some other UI technology that mangles field names, you’ll need to account for this.
• You may have something else incorrectly configured
  • Suggestion: Remove your custom UserDetailsService and replace it with the standard, simple, in-memory service, to make sure your basic configuration works before augmenting with custom stuff.

If you can post your full configuration (specifically noting whatever you have customized), I/we can offer more precise advice, but I would suggest that one of these things is most likely to be your problem.