我遵循了这里提到的一些建议，但对我没有用。因此，将问题放在这里

谁能指导我这是什么问题以及如何解决？

错误：

***************************
APPLICATION FAILED TO START
***************************

Description:

Field authenticationManager in com.techprimers.security.springsecurityauthserver.config.AuthorizationServerConfig required a bean of type 'org.springframework.security.authentication.AuthenticationManager' that could not be found.


Action:

Consider defining a bean of type 'org.springframework.security.authentication.AuthenticationManager' in your configuration.

AuthorizationServerConfig.java

@Configuration
@EnableAuthorizationServer
public class AuthorizationServerConfig extends AuthorizationServerConfigurerAdapter {

    @Autowired
    private AuthenticationManager authenticationManager;

    @Override
    public void configure(AuthorizationServerSecurityConfigurer security) throws Exception {

        security.tokenKeyAccess("permitAll()")
                .checkTokenAccess("isAuthenticated()");
    }


    @Override
    public void configure(ClientDetailsServiceConfigurer clients) throws Exception {
        clients
                .inMemory()
                .withClient("ClientId")
                .secret("secret")
                .authorizedGrantTypes("authorization_code")
                .scopes("user_info")
                .autoApprove(true);
    }


    @Override
    public void configure(AuthorizationServerEndpointsConfigurer endpoints) throws Exception {

        endpoints.authenticationManager(authenticationManager);
    }
}

ResourceServerConfig.java

@EnableResourceServer
@Configuration
public class ResourceServerConfig extends WebSecurityConfigurerAdapter {


    @Autowired
    @Qualifier("authenticationManagerBean")
    private AuthenticationManager authenticationManager;
    @Autowired
    private UserDetailsService customUserDetailsService;

    @Override
    protected void configure(HttpSecurity http) throws Exception {

        http.requestMatchers()
                .antMatchers("/login", "/oauth/authorize")
                .and()
                .authorizeRequests()
                .anyRequest()
                .authenticated()
                .and()
                .formLogin()
                .permitAll();
    }


    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.parentAuthenticationManager(authenticationManager)
                .userDetailsService(customUserDetailsService);
    }
}

取自https://github.com/TechPrimers/spring-security-oauth-mysql-
example的代码参考，仅将Spring Boot Parent Version更新为2.0.4.RELEASE，事情开始中断。