Autowired in CustomInterceptor gets null (Spring Boot)

Question

I want to do a check in the database when I receive a request. So I made an interceptor as shown below,

CustomInterceptor.java

@Component
public class CustomInterceptor extends HandlerInterceptorAdapter {

@Autowired
private DatabaseService databaseService;

@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    //Set Request Attribute(TODO)
    LogService.info(this.getClass().getName(), "New Request URI is:" + request.getRequestURI());
    return true;
}

@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    String authToken = request.getHeader("AuthToken");
        boolean isValidRequest = databaseService.checkIfTokenIsValid(authToken);
    }
}

Application.class:

@SpringBootApplication
public class Application extends SpringBootServletInitializer {

//    protected Properties props = new Properties();
//
//    public Application() {
//        props.setProperty("error.path", "/error");
////        props.setProperty("error.whitelabel.enabled", "false");
////        props.setProperty("org.springframework.web", "DEBUG");
//    }
@Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
//        application.properties(props);
    return application.sources(Application.class);
}

@Override
public void onStartup(final ServletContext servletContext) throws ServletException {
    LogService.info(Application.class.getName(), "Loading Service...");
    super.onStartup(servletContext);
    LogService.info(Application.class.getName(), "Service Started");
}

public static void main(String[] args) {
    ApplicationContext context = SpringApplication.run(Application.class, args);
}

DatabasService.java

@Service
public class DatabaseService {


@Autowired
private ApplicationProperties properties;

private final JdbcTemplate defaultJdbcTemplate;

@Autowired
public DatabaseService(
        @Qualifier("dataSource") DataSource dataSource) {
    defaultJdbcTemplate = new JdbcTemplate(dataSource);
}

public boolean checkIfTokenIsValid() {
    //Perform Check
 }
}

CustomWebConfiguration.java

@Configuration
@EnableWebMvc
public class CustomWebConfiguration extends WebMvcConfigurerAdapter {

private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
    "classpath:/META-INF/resources/", "classpath:/resources/",
    "classpath:/static/", "classpath:/public/"};

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
    if (!registry.hasMappingForPattern("/**")) {
        registry.addResourceHandler("/**").addResourceLocations(
                CLASSPATH_RESOURCE_LOCATIONS);
    }
}

@Override
public void addInterceptors(InterceptorRegistry registry) {
    registry.addInterceptor(new CustomInterceptor())
            .addPathPatterns("/**");
}

}

But I get NullPointer At: boolean isValidRequest = databaseService.checkIfTokenIsValid(authToken);

What is wrong here, why can't spring Autowire Databaseservice in Interceptor?

Note. Autowire works great everywhere, but not in the interceptor.

Solution (thanks to M. Deinum) Modify CustomWebConfiguration.java as shown below;

@Configuration
@EnableWebMvc
public class CustomWebConfiguration extends WebMvcConfigurerAdapter {

private static final String[] CLASSPATH_RESOURCE_LOCATIONS = {
    "classpath:/META-INF/resources/", "classpath:/resources/",
    "classpath:/static/", "classpath:/public/"};

@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
    if (!registry.hasMappingForPattern("/**")) {
        registry.addResourceHandler("/**").addResourceLocations(
                CLASSPATH_RESOURCE_LOCATIONS);
     }
    }

@Bean
public CustomInterceptor customInterceptor() {
    return new CustomInterceptor();
}

@Override
public void addInterceptors(InterceptorRegistry registry) {
    registry.addInterceptor(customInterceptor())
            .addPathPatterns("/**");
 }
}

Answer 1

Spring will only autowire beans, which he knows about, you create an instance yourself out of Spring control.

CustomInterceptor , @Bean, Spring. , .

Answer 2

@SpringBootApplication , @EnableAutoConfiguration @ComponentScan , Spring Boot ?