How to inject Service in Java Filter

A problem was encountered in the project, and injecting Serivce failed in the filter, and the injected service is always null. As shown below:

 Public class Implements filter{        @Autowired    private usersservice usersservice;

The Filterchain times null pointer exception is used in the public void DoFilter (ServletRequest request, servletresponse response, Chain Usersservice) method.

Workaround:

 Public voidDoFilter (ServletRequest request, servletresponse response, Filterchain chain)throwsIOException, servletexception {httpservletrequest req=(httpservletrequest) request; HttpServletResponse resp=(httpservletresponse) response; Xmlwebapplicationcontext Context=(Xmlwebapplicationcontext) webapplicationcontextutils.
Getwebapplicationcontext (Req.getsession (). Getservletcontext ()); if(Context! =NULL&& Context.getbean ("Usersservice")! =NULL&& Usersservice = =NULL) Usersservice= (Usersservice) context.getbean ("Usersservice"); Users Users= This. Usersservice.querybyopenid (OpenID);

That's all.

How to inject Service in Java Filter