添加WebSecurityConfigurerAdapter时Spring Security默认登录表单消失

我有Spring Boot 2一些控制器的应用程序。
我想添加Spring Security 一些URL，仅允许经过身份验证的用户使用，而其他URL应该可供所有人使用。
但是，当我用于WebSecurityConfigurerAdapter配置每个URL的安全性时，“ / login”和“ / error”的自动生成页面消失了。

如果我尝试添加最简单的可能配置，那么它将起作用并保护所有网址：

application.yml

spring:
  security:
    user:
      name: "admin"
      password: "1234"
      roles: "ADMIN"

pom.xml：

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
    </dependencies>

并且所有操作都会将我重定向到/login带有登录表单的页面，直到我使用配置的凭据登录为止。

但是，如果我添加一个配置类来自定义行为，则似乎缺少默认的登录表单，而我一直在获取/error页面，因为没有这样的资源/login：

@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth
                .inMemoryAuthentication()
                .withUser("admin").password("1234").roles("ADMIN");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                .authorizeRequests()
                .antMatchers("/private").hasRole("ADMIN")
                .antMatchers("/public").permitAll()
                .antMatchers("/", "/login", "/logout", "/error").permitAll()
                .antMatchers("/**").denyAll();
    }
}

以下是一些调试日志（为便于阅读，省略了其余日志）：

DEBUG o.s.s.w.a.AnonymousAuthenticationFilter - Populated SecurityContextHolder with anonymous token: 'org.springframework.security.authentication.AnonymousAuthenticationToken@e4de2840: Principal: anonymousUser; Credentials: [PROTECTED]; Authenticated: true; Details: org.springframework.security.web.authentication.WebAuthenticationDetails@b364: RemoteIpAddress: 0:0:0:0:0:0:0:1; SessionId: null; Granted Authorities: ROLE_ANONYMOUS'
...
DEBUG o.s.s.w.u.m.AntPathRequestMatcher - Checking match of request : '/login'; against '/login'
DEBUG o.s.s.w.a.i.FilterSecurityInterceptor - Secure object: FilterInvocation: URL: /login; Attributes: [permitAll]
DEBUG o.s.s.w.a.i.FilterSecurityInterceptor - Previously Authenticated: org.springframework.security.authentication.AnonymousAuthenticationToken@e4de2840: Principal: anonymousUser; Credentials: [PROTECTED]; Authenticated: true; Details: org.springframework.security.web.authentication.WebAuthenticationDetails@b364: RemoteIpAddress: 0:0:0:0:0:0:0:1; SessionId: null; Granted Authorities: ROLE_ANONYMOUS
DEBUG o.s.s.access.vote.AffirmativeBased - Voter: org.springframework.security.web.access.expression.WebExpressionVoter@2a3c0a9c, returned: 1
DEBUG o.s.s.w.a.i.FilterSecurityInterceptor - Authorization successful
DEBUG o.s.s.w.a.i.FilterSecurityInterceptor - RunAsManager did not change Authentication object
DEBUG o.s.security.web.FilterChainProxy - /login reached end of additional filter chain; proceeding with original chain
DEBUG o.s.web.servlet.DispatcherServlet - GET "/login", parameters={}
DEBUG o.s.w.s.h.SimpleUrlHandlerMapping - Mapped to ResourceHttpRequestHandler ["classpath:/META-INF/resources/", "classpath:/resources/", "classpath:/static/", "classpath:/public/", "/"]
DEBUG o.s.o.j.s.OpenEntityManagerInViewInterceptor - Opening JPA EntityManager in OpenEntityManagerInViewInterceptor
DEBUG o.s.w.s.r.ResourceHttpRequestHandler - Resource not found
DEBUG o.s.s.w.h.writers.HstsHeaderWriter - Not injecting HSTS header since it did not match the requestMatcher org.springframework.security.web.header.writers.HstsHeaderWriter$SecureRequestMatcher@27581ee6
DEBUG o.s.s.w.c.HttpSessionSecurityContextRepository - SecurityContext is empty or contents are anonymous - context will not be stored in HttpSession.
DEBUG o.s.o.j.s.OpenEntityManagerInViewInterceptor - Closing JPA EntityManager in OpenEntityManagerInViewInterceptor
DEBUG o.s.web.servlet.DispatcherServlet - Completed 404 NOT_FOUND
DEBUG o.s.s.w.a.ExceptionTranslationFilter - Chain processed normally
DEBUG o.s.s.w.c.SecurityContextPersistenceFilter - SecurityContextHolder now cleared, as request processing completed
DEBUG o.s.security.web.FilterChainProxy - /error at position 1 of 11 in additional filter chain; firing Filter: 'WebAsyncManagerIntegrationFilter'
...
DEBUG o.s.security.web.FilterChainProxy - /error reached end of additional filter chain; proceeding with original chain
DEBUG o.s.web.servlet.DispatcherServlet - "ERROR" dispatch for GET "/error", parameters={}
DEBUG o.s.w.s.m.m.a.RequestMappingHandlerMapping - Mapped to org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController#errorHtml(HttpServletRequest, HttpServletResponse)
DEBUG o.s.o.j.s.OpenEntityManagerInViewInterceptor - Opening JPA EntityManager in OpenEntityManagerInViewInterceptor
DEBUG o.s.w.s.v.ContentNegotiatingViewResolver - Selected 'text/html' given [text/html, text/html;q=0.8]
DEBUG o.s.o.j.s.OpenEntityManagerInViewInterceptor - Closing JPA EntityManager in OpenEntityManagerInViewInterceptor
DEBUG o.s.web.servlet.DispatcherServlet - Exiting from "ERROR" dispatch, status 404
DEBUG o.s.s.w.a.ExceptionTranslationFilter - Chain processed normally
DEBUG o.s.s.w.c.HttpSessionSecurityContextRepository - SecurityContext is empty or contents are anonymous - context will not be stored in HttpSession.
DEBUG o.s.s.w.c.SecurityContextPersistenceFilter - SecurityContextHolder now cleared, as request processing completed

最后，我在浏览器中看到错误页面，说也没有/error页面。

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Jan 21 14:53:17 CET 2020
There was an unexpected error (type=Not Found, status=404).
Not Found

由于某些原因，当我使用WebSecurityConfigurerAdapter配置类时，“ / login”和“ / error”的自动生成的页面会消失。他们去哪了？

而且，这Previously Authenticated:对我来说似乎很可疑，因为这是一个全新的应用程序开始。但是，如果我尝试使用禁用匿名用户http.anonymous().disable()，则对于任何网址，我都会开始收到403错误。可以关联吗？