Spring boot 2+ Could not Autowire. There is more than one bean of 'UserDetailsService'

Question

Hello Everyone i'm new in spring security and jwt. I'm implementing Jwt in my spring boot project to secure user login and i'm using spring boot 2.1.5 and i don't know much about new bean restriction in spring boot 2+ . I need some help .. here i'm trying to @Autowired UserDetailsService and code run fine ..and result is also fine.. but intellij shows error at

@Autowired UserDetailsService jwtUserDetailsService

saying ... Could not autowire. There is more than one bean of UserDetailsService type.

Can anyone explain me what what happens wrong here why i can't autowired and why and what are the Autowired restriction in spring boot 2+ ?

And thanks in advance

@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
public class WebSecurity extends WebSecurityConfigurerAdapter {

    @Autowired
    private JwtAuthenticationEntryPoint jwtAuthenticationEntryPoint;

    @Autowired
    private PasswordEncoder passwordEncoder;

    @Autowired
    private JwtFilter jwtFilter;

    @Autowired
    private UserDetailsService jwtUserDetailsService; // here i got error only

    @Autowired
    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.userDetailsService(jwtUserDetailsService).passwordEncoder(passwordEncoder);
    }

    @Bean
    @Override
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().disable();
        http.authorizeRequests().antMatchers("/api/user/add", "/generate").permitAll().anyRequest().authenticated().and()            .exceptionHandling().authenticationEntryPoint(jwtAuthenticationEntryPoint)
                .and().sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS);
        http.addFilterBefore(jwtFilter, UsernamePasswordAuthenticationFilter.class);
    }
}

my customUserDetailService is

@Service
public class JwtUserDetailService implements UserDetailsService {

    @Autowired
    private UserRepository userRepository;

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        User user = userRepository.findByUsername(username);
        if (user != null) {
            return new org.springframework.security.core.userdetails.User(user.getUsername(), user.getPassword(), new ArrayList<>());
        } else {
            throw new UsernameNotFoundException("Username does't exists");
        }

    }
}

My JwtController class which expose restend point to generate jwt token

@CrossOrigin
@RestController
public class JwtController {

    @Autowired
    private JwtUtils jwtUtils;

    @Autowired
    private AuthenticationManager authenticationManager;
    @Autowired
    private JwtUserDetailService jwtUserDetailService;

    @PostMapping(value = "/generate")
    public ResponseEntity<?> generateToken(@RequestBody JwtRequest jwtRequest) throws Exception {
        try {
            authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(jwtRequest.getUsername(),
                    jwtRequest.getPassword()));
        } catch (DisabledException e) {
            throw new Exception("USER_DISABLED", e);
        } catch (BadCredentialsException e) {
            throw new Exception("INVAILD_CREDENTIALS", e);
        }
        final UserDetails userDetails = jwtUserDetailService.loadUserByUsername(jwtRequest.getUsername());
        final String token = jwtUtils.generateToken(userDetails);

        return ResponseEntity.ok(new JwtResponse(token));
    }
}

My JwtFilter Class

@Component
public class JwtFilter extends OncePerRequestFilter {

    @Autowired
    private JwtUserDetailService jwtUserDetailService;

    @Autowired
    private JwtUtils jwtUtils;

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
            throws ServletException, IOException {

        final String requestTokenHeader = request.getHeader("Authorization");

        String username = null;
        String jwtToken = null;

        if (requestTokenHeader != null && requestTokenHeader.startsWith("Bearer ")) {
            jwtToken = requestTokenHeader.substring(7);
            try {
                username = jwtUtils.getUsernameFromToken(jwtToken);
            } catch (IllegalArgumentException e) {
                System.out.println("Unable to get JWT Token");
            } catch (ExpiredJwtException e) {
                System.out.println("JWT Token has expired");
            }
        } else {
            logger.warn("JWT Token does not begin with Bearer String");
        }

        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {

            UserDetails userDetails = this.jwtUserDetailService.loadUserByUsername(username);

            if (jwtUtils.validate(jwtToken, userDetails)) {

                UsernamePasswordAuthenticationToken usernamePasswordAuthenticationToken = new UsernamePasswordAuthenticationToken(
                        userDetails, null, userDetails.getAuthorities());
                usernamePasswordAuthenticationToken
                        .setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
               SecurityContextHolder.getContext().setAuthentication(usernamePasswordAuthenticationToken);
            }
        }
        chain.doFilter(request, response);
    }

}

Other thing as just normal like entity, repository, and some secured restend points

Answer 1

I got the same error in another context. The reason was the Idea don´t know which bean of type 'UserDetailsService' to use. My solution is through annotation Qualifier:

@Qualifier("beanNameWhichYouWantUse")
@Autowired
private UserDetailsService jwtUserDetailsService;

If use Idea: give mouse point on the error, select from context menu:

"More actions" -> "Add qualifier"

and finally select the bean

Answer 2

UserDetailsService was provided by spring. To Autowire you need to configure it with.

@Bean
public UserDetailsService getUserDetails(){
   return new JwtUserDetailService(); // Implementation class
}

If you are not interested in Bean Configuration. you can autowire JwtUserDetailService directly.

@Autowired
private JwtUserDetailService jwtUserDetailsService;