Para resolver o authenticationManager

Olá pessoal, uma sugestão de atualização. Como na nova versão do Spring Security não tem o método authenticationManager(), o que pode fazer é injetar o AuthenticationConfiguration no construtor da classe e usar o authenticationManager dele. Ficou assim o código:

@Configuration
@EnableWebSecurity
class SecurityConfiguration (
    private val configuration: AuthenticationConfiguration,
    private val userDetailsService: UserDetailsService,
    private val jwtUtil: JWTUtil
){

    @Bean
    fun securityFilterChain(http: HttpSecurity): SecurityFilterChain {
        return http
            .csrf { it.disable() }
            .authorizeHttpRequests {
                it
                    .requestMatchers(HttpMethod.POST, "/login").permitAll()
                    .anyRequest().authenticated()
            }
            .addFilterBefore(JWTLoginFilter(authenticationManager = configuration.authenticationManager, jwtUtil = jwtUtil), UsernamePasswordAuthenticationFilter().javaClass)
            .sessionManagement {
                it.sessionCreationPolicy(SessionCreationPolicy.STATELESS)
            }.build()
    }

    @Bean
    fun encoder(): PasswordEncoder = BCryptPasswordEncoder()

}

O filter, que vai ser apresentado na aula seguinte, ficou assim:

class JWTLoginFilter(
    private val authenticationManager: AuthenticationManager?,
    private val jwtUtil: JWTUtil,
) : UsernamePasswordAuthenticationFilter(authenticationManager) {

    override fun attemptAuthentication(request: HttpServletRequest?, response: HttpServletResponse?): Authentication? {
        val (username, password) = ObjectMapper().readValue(request?.inputStream, Credentials::class.java)
        val token = UsernamePasswordAuthenticationToken(username, password)
        return authenticationManager?.authenticate(token)
    }

    override fun successfulAuthentication(
        request: HttpServletRequest?,
        response: HttpServletResponse?,
        chain: FilterChain?,
        authResult: Authentication?
    ) {
        val username = (authResult?.principal as UserDetails).username
        val token = jwtUtil.generateToken(username)
        response?.addHeader("Authorization", "Bearer $token")
    }
}

Aqui funcionou perfeitamente.