调用第二个AuthenticationProvider的原因

Question

我的Spring Boot应用程序中有以下WebSecurityConfig的Spring Security。

@EnableWebSecurity
public class WebSecurityConfig {

    @Configuration
    @Order(1)
    public static class Form1LoginWebSecurityConfigurerAdapter extends WebSecurityConfigurerAdapter {

        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http
            .antMatcher("/uid/serverinfo.html")
            .authorizeRequests()
                .antMatchers("/admins/login")
                .permitAll()
                .antMatchers("/uid/serverinfo.html")
                .authenticated()
            .and()
                .formLogin()
                .loginProcessingUrl("/admins/login")
                .loginPage("/admins/login")
                .failureUrl("/admins/login?error")
                .defaultSuccessUrl("/uid/serverinfo.html");
        }

        @Override
        public void configure(AuthenticationManagerBuilder auth) throws Exception {
            auth.authenticationProvider(authenticationProvider());
        }

        @Bean
        public AuthenticationProvider authenticationProvider() {
            return new LDAPAuthenticationProvider();
        }
    }

    @Configuration
    @Order(2)
    public static class Form2LoginWebSecurityConfigurerAdapter extends WebSecurityConfigurerAdapter {

        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http
            .antMatcher("/admins/**")
            .authorizeRequests()
                .antMatchers("/admins/login")
                .permitAll()
                .antMatchers("/admins/**")
                .authenticated()
            .and()
                .formLogin()
                .loginProcessingUrl("/admins/login")
                .loginPage("/admins/login")
                .failureUrl("/admins/login?error")
                .defaultSuccessUrl("/admins/main");
        }

        @Override
        public void configure(AuthenticationManagerBuilder auth) throws Exception {
            auth.authenticationProvider(authenticationProvider());
        }

        @Bean
        public AuthenticationProvider authenticationProvider() {
            return new RDBAuthenticationProvider();
        }
    }
}

如果访问http:localhost:8080/admins/main，我的预期结果为RDBAuthenticationProvider.authenticate()，但实际上会调用LDAPAuthenticationProvider.authenticate()。

有谁知道原因以及如何解决？