Spring Security(3)：配置与自动配置的介绍及源码分析
基于注解的配置（Java Configuration）从Spring Security 3.2开始就已经支持，本篇基于Spring boot注解的配置进行讲解，如果需要基于XML配置（Security Namespace Configuration），可查阅Spring Security官网：https://docs.spring.io/spring-security/site/docs/5.1.5.RELEASE/reference/htmlsingle/#ns-config
基于Maven的Spring及Spring Boot配置不再赘述，想要配置Spring Security，只需要@EnableWebSecurity注解。如果需要自定义一些配置，则需要和继承WebSecurityConfigurerAdapter后，覆盖某些方法：
@EnableWebSecuritypublic class MySecurityConfig extends WebSecurityConfigurerAdapter { }
本节主要讲通过@EnableWebSecurity的默认配置。下节来讲通过继承WebSecurityConfigurerAdapter的自定义配置。
[2019/06/04 ADD]
在SpringBoot中，只要你加入spring-boot-starter-security包到项目中，即使不配置@EnableWebSecurity和WebSecurityConfigurerAdapter，SpringBoot也会自动给我们添加这两个配置。具体可以看SpringBootWebSecurityConfiguration及WebSecurityEnablerConfiguration。
/** * The default configuration for web security. It relies on Spring Security's * content-negotiation strategy to determine what sort of authentication to use. If the * user specifies their own {@link WebSecurityConfigurerAdapter}, this will back-off * completely and the users should specify all the bits that they want to configure as * part of the custom security configuration. * * @author Madhura Bhave * @since 2.0.0 */@Configuration@ConditionalOnClass(WebSecurityConfigurerAdapter.class)@ConditionalOnMissingBean(WebSecurityConfigurerAdapter.class)@ConditionalOnWebApplication(type = Type.SERVLET)public class SpringBootWebSecurityConfiguration { @Configuration @Order(SecurityProperties.BASIC_AUTH_ORDER) static class DefaultConfigurerAdapter extends WebSecurityConfigurerAdapter { }}
/** * If there is a bean of type WebSecurityConfigurerAdapter, this adds the * {@link EnableWebSecurity} annotation. This will make sure that the annotation is * present with default security auto-configuration and also if the user adds custom * security and forgets to add the annotation. If {@link EnableWebSecurity} has already * been added or if a bean with name {@value BeanIds#SPRING_SECURITY_FILTER_CHAIN} has * been configured by the user, this will back-off. * * @author Madhura Bhave * @since 2.0.0 */@Configuration@ConditionalOnBean(WebSecurityConfigurerAdapter.class)@ConditionalOnMissingBean(name = BeanIds.SPRING_SECURITY_FILTER_CHAIN)@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)@EnableWebSecuritypublic class WebSecurityEnablerConfiguration {}
@EnableWebSecurity虽然只是一个注解，但它实际上做了许多事。下面是丛Spring Security官网摘录下来的：
(1) Require authentication to every URL in your application #在你的应用程序中对每个URL进行验证(2) Generate a login form for you #为你生成一个登录表单(3) Allow the user with the Username user and the Password password to authenticate with form based authentication #允许使用用户名和密码使用验证表单进行验证(4) Allow the user to logout #允许用户登出(5) CSRF attack prevention #CSRF attack攻击防范(6) Session Fixation protection #Session Fixation Session保护(7) Security Header integration #安全Header集成 - HTTP Strict Transport Security for secure requests #严格的HTTP传输安全 - X-Content-Type-Options integration - Cache Control (can be overridden later by your application to allow caching of your static resources) - X-XSS-Protection integration - X-Frame-Options integration to help prevent Clickjacking(8) Integrate with the following Servlet API methods #以下Servlet API方法集成 - HttpServletRequest#getRemoteUser() - HttpServletRequest.html#getUserPrincipal() - HttpServletRequest.html#isUserInRole(java.lang.String) - HttpServletRequest.html#login(java.lang.String, java.lang.String) - HttpServletRequest.html#logout()
这么多功能是怎么实现的呢？我们可以查看@EnableWebSecurity的源码，发现该注解会配置3个配置类：
@EnableWebSecurity -> WebSecurityConfiguration.class，WebMvcSecurityConfiguration.class(condition is DispatcherServlet is present)，OAuth2ImportSelector.class(condition is OAuth2ClientConfiguration is present)
@EnableWebSecurity -> @EnableGlobalAuthentication -> AuthenticationConfiguration.class
其中，WebSecurityConfiguration是最主要的配置类。WebMvcSecurityConfiguration，OAuth2ImportSelector这里不再介绍。由于在加载WebSecurityConfiguration的过程中需要用到AuthenticationConfiguration Bean，所以，节下来我们只讲WebSecurityConfiguration。
下面是WebSecurityConfiguration类的源码：
/** * Uses a {@link WebSecurity} to create the {@link FilterChainProxy} that performs the web * based security for Spring Security. It then exports the necessary beans. Customizations * can be made to {@link WebSecurity} by extending {@link WebSecurityConfigurerAdapter} * and exposing it as a {@link Configuration} or implementing * {@link WebSecurityConfigurer} and exposing it as a {@link Configuration}. This * configuration is imported when using {@link EnableWebSecurity}. * * @see EnableWebSecurity * @see WebSecurity * * @author Rob Winch * @author Keesun Baik * @since 3.2 */@Configurationpublic class WebSecurityConfiguration implements ImportAware, BeanClassLoaderAware { }
通过注释可以总结为以下几点：
（1）创建了WebSecurity及上节讲的Security Filter Chain（List<SecurityFilterChain>）的代理对象FilterChainProxy Bean。
（2）创建了其他一些必要的Bean。
（3）如果需要自定义WebSecurity的一些内容，可以继承WebSecurityConfigurerAdapter类或直接实现WebSecurityConfigurer接口，然后在去重写相应方法。当然要用@Configuration声明它为配置类（@EnableWebSecurity中有@Configuration注解，不需要重复添加）。
（A）构建WebSecurity
初始化：WebSecurityConfiguration会先执行一个set方法（通过set方法注入的Bean List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers）:
@Configurationpublic class WebSecurityConfiguration implements ImportAware, BeanClassLoaderAware { private List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers; /** * Sets the {@code <SecurityConfigurer<FilterChainProxy, WebSecurityBuilder>} * instances used to create the web configuration. * * @param objectPostProcessor the {@link ObjectPostProcessor} used to create a * {@link WebSecurity} instance * @param webSecurityConfigurers the * {@code <SecurityConfigurer<FilterChainProxy, WebSecurityBuilder>} instances used to * create the web configuration * @throws Exception */ @Autowired(required = false) public void setFilterChainProxySecurityConfigurer( ObjectPostProcessor<Object> objectPostProcessor, @Value("#{@autowiredWebSecurityConfigurersIgnoreParents.getWebSecurityConfigurers()}") List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers) // [1.2] throws Exception { webSecurity = objectPostProcessor .postProcess(new WebSecurity(objectPostProcessor)); // [1.4] if (debugEnabled != null) { webSecurity.debug(debugEnabled); } Collections.sort(webSecurityConfigurers, AnnotationAwareOrderComparator.INSTANCE); Integer previousOrder = null; Object previousConfig = null; for (SecurityConfigurer<Filter, WebSecurity> config : webSecurityConfigurers) { Integer order = AnnotationAwareOrderComparator.lookupOrder(config); if (previousOrder != null && previousOrder.equals(order)) { // [1.3] throw new IllegalStateException( "@Order on WebSecurityConfigurers must be unique. Order of " + order + " was already used on " + previousConfig + ", so it cannot be used on " + config + " too."); } previousOrder = order; previousConfig = config; } for (SecurityConfigurer<Filter, WebSecurity> webSecurityConfigurer : webSecurityConfigurers) { webSecurity.apply(webSecurityConfigurer); // [1.5] } this.webSecurityConfigurers = webSecurityConfigurers; } @Bean // [1.1] public static AutowiredWebSecurityConfigurersIgnoreParents autowiredWebSecurityConfigurersIgnoreParents( ConfigurableListableBeanFactory beanFactory) { return new AutowiredWebSecurityConfigurersIgnoreParents(beanFactory); }}
[1.1] 用static先声明一个autowiredWebSecurityConfigurersIgnoreParents Bean。
[1.2] 这个方法先通过@Value注解通过调用[1.1]的AutowiredWebSecurityConfigurersIgnoreParents.getWebSecurityConfigurers()获取ApplicationContext中所有的WebSecurityConfigurer。具体可以看一下AutowiredWebSecurityConfigurersIgnoreParents的源码。
/** * A class used to get all the {@link WebSecurityConfigurer} instances from the current * {@link ApplicationContext} but ignoring the parent. * * @author Rob Winch * */final class AutowiredWebSecurityConfigurersIgnoreParents { private final ConfigurableListableBeanFactory beanFactory; public AutowiredWebSecurityConfigurersIgnoreParents( ConfigurableListableBeanFactory beanFactory) { Assert.notNull(beanFactory, "beanFactory cannot be null"); this.beanFactory = beanFactory; } @SuppressWarnings({ "rawtypes", "unchecked" }) public List<SecurityConfigurer<Filter, WebSecurity>> getWebSecurityConfigurers() { List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers = new ArrayList<SecurityConfigurer<Filter, WebSecurity>>(); Map<String, WebSecurityConfigurer> beansOfType = beanFactory .getBeansOfType(WebSecurityConfigurer.class); for (Entry<String, WebSecurityConfigurer> entry : beansOfType.entrySet()) { webSecurityConfigurers.add(entry.getValue()); } return webSecurityConfigurers; }}
通常情况下这个WebSecurityConfigurer List只有一个元素，并且就是我们自己继承WebSecurityConfigurerAdapter配置的MySecurityConfig。
@EnableWebSecuritypublic class MySecurityConfig extends WebSecurityConfigurerAdapter { }
在SpringBoot自动配置的情况下，如果我们没有继承，则系统默认会使用SpringBootWebSecurityConfiguration的DefaultConfigurerAdapter。
/** * The default configuration for web security. It relies on Spring Security's * content-negotiation strategy to determine what sort of authentication to use. If the * user specifies their own {@link WebSecurityConfigurerAdapter}, this will back-off * completely and the users should specify all the bits that they want to configure as * part of the custom security configuration. * * @author Madhura Bhave * @since 2.0.0 */@ConditionalOnClass(WebSecurityConfigurerAdapter.class) // 有这个对象@ConditionalOnMissingBean(WebSecurityConfigurerAdapter.class) // 但是没有声明这个bean@ConditionalOnWebApplication(type = Type.SERVLET)public class SpringBootWebSecurityConfiguration { @Configuration // 声明一个DefaultConfigurerAdapter的配置Bean @Order(SecurityProperties.BASIC_AUTH_ORDER) static class DefaultConfigurerAdapter extends WebSecurityConfigurerAdapter { }}
[1.3] WebSecurityConfigurer如果有多个的情况下，要对他们的@Order进行检查，不能有相同的Order。
[1.4][1.5] 初始化WebSecurity，并将SecurityConfigurer（WebSecurityConfigurerAdapter）应用于此SecurityBuilder（WebSecurity），覆盖完全相同类的任何SecurityConfigurer。
构建：WebSecurity如何被初始化后，就开始构建，下面就是WebSecurityConfiguration中WebSecurity的构建方法，该方法声明为一个Bean，返回的其实就是上一节讲的Spring Security Filter Chain。
/** * Creates the Spring Security Filter Chain * @return the {@link Filter} that represents the security filter chain * @throws Exception */ @Bean(name = AbstractSecurityWebApplicationInitializer.DEFAULT_FILTER_NAME) public Filter springSecurityFilterChain() throws Exception { boolean hasConfigurers = webSecurityConfigurers != null && !webSecurityConfigurers.isEmpty(); if (!hasConfigurers) { WebSecurityConfigurerAdapter adapter = objectObjectPostProcessor .postProcess(new WebSecurityConfigurerAdapter() { }); webSecurity.apply(adapter); } return webSecurity.build(); }
WebSecurity的构建过程很复杂，大概走了下面几步流程：
[1.1] 调用AbstractSecurityBuilder.build()方法。
[1.2] 调用AbstractConfiguredSecurityBuilder.doBuild()方法（核心方法）。
@Override protected final O doBuild() throws Exception { synchronized (configurers) { buildState = BuildState.INITIALIZING; beforeInit(); // Do nothing if no child class override it. init(); // [1.2.1] buildState = BuildState.CONFIGURING; beforeConfigure(); // Do nothing if no child class override it. configure(); // [1.2.2] buildState = BuildState.BUILDING; O result = performBuild(); // [1.2.3] buildState = BuildState.BUILT; return result; } }
[1.2.1] 调用WebSecurityConfigurerAdapter的init(final WebSecurity web)方法。这里构建了HttpSecurity对象，把HttpSecurity添加到WebSecurity的securityFilterChainBuilders中（用于构建过滤器链）以及有一个共享对象FilterSecurityInterceptor。HttpSecurity的构建下面会重点介绍，这里先略过。
public void init(final WebSecurity web) throws Exception { final HttpSecurity http = getHttp(); // 构建HttpSecurity对象 web.addSecurityFilterChainBuilder(http).postBuildAction(new Runnable() { // 把该对象添加到WebSecurity对象中用于接下来[1.2.3]构建过滤器链，可以看下面WebSecurity的 // addSecurityFilterChainBuilder()方法 public void run() { FilterSecurityInterceptor securityInterceptor = http .getSharedObject(FilterSecurityInterceptor.class); web.securityInterceptor(securityInterceptor); } }); }
public final class WebSecurity extends AbstractConfiguredSecurityBuilder<Filter, WebSecurity> implements SecurityBuilder<Filter>, ApplicationContextAware { private final List<SecurityBuilder<? extends SecurityFilterChain>> securityFilterChainBuilders = new ArrayList<SecurityBuilder<? extends SecurityFilterChain>>(); /** * <p> * Adds builders to create {@link SecurityFilterChain} instances. * </p> * * <p> * Typically this method is invoked automatically within the framework from * {@link WebSecurityConfigurerAdapter#init(WebSecurity)} * </p> * * @param securityFilterChainBuilder the builder to use to create the * {@link SecurityFilterChain} instances * @return the {@link WebSecurity} for further customizations */ public WebSecurity addSecurityFilterChainBuilder( SecurityBuilder<? extends SecurityFilterChain> securityFilterChainBuilder) { this.securityFilterChainBuilders.add(securityFilterChainBuilder); return this; }}
[1.2.2] 调用WebSecurityConfigurerAdapter的configure(WebSecurity web)，但是什么都没做。我们可以通过继承WebSecurityConfigurerAdapter来覆盖该方法来自定义配置WebSecurity。
[1.2.3] 调用WebSecurity的performBuild()方法，用[1.2.1]的securityFilterChainBuilders构建过滤器链，并交给FilterChainProxy代理，并返回。值得一说的是，FilterChainProxy最终委托给DelegatingFilterProxy来执行，后者也是web.xml的Security配置项（来源于FilterChainProxy的类注释）。
@Override protected Filter performBuild() throws Exception { Assert.state( !securityFilterChainBuilders.isEmpty(), () -> "At least one SecurityBuilder<? extends SecurityFilterChain> needs to be specified. " + "Typically this done by adding a @Configuration that extends WebSecurityConfigurerAdapter. " + "More advanced users can invoke " + WebSecurity.class.getSimpleName() + ".addSecurityFilterChainBuilder directly"); int chainSize = ignoredRequests.size() + securityFilterChainBuilders.size(); List<SecurityFilterChain> securityFilterChains = new ArrayList<>( chainSize); for (RequestMatcher ignoredRequest : ignoredRequests) { securityFilterChains.add(new DefaultSecurityFilterChain(ignoredRequest)); } for (SecurityBuilder<? extends SecurityFilterChain> securityFilterChainBuilder : securityFilterChainBuilders) { securityFilterChains.add(securityFilterChainBuilder.build()); } FilterChainProxy filterChainProxy = new FilterChainProxy(securityFilterChains); if (httpFirewall != null) { filterChainProxy.setFirewall(httpFirewall); } filterChainProxy.afterPropertiesSet(); Filter result = filterChainProxy; if (debugEnabled) { logger.warn("\n\n" + "********************************************************************\n" + "********** Security debugging is enabled. *************\n" + "********** This may include sensitive information. *************\n" + "********** Do not use in a production system! *************\n" + "********************************************************************\n\n"); result = new DebugFilter(filterChainProxy); } postBuildAction.run(); return result; }
（B）构建HttpSecurity
在WebSecurity的构建过程中，在调用WebSecurityConfigurerAdapter的init(final WebSecurity web)方法时（见上面的[1.2.1] ），调用WebSecurityConfigurerAdapter的getHttp()构建了HttpSecurity对象。
protected final HttpSecurity getHttp() throws Exception { if (http != null) { return http; } // The default strategy for publishing authentication events DefaultAuthenticationEventPublisher eventPublisher = objectPostProcessor .postProcess(new DefaultAuthenticationEventPublisher()); localConfigureAuthenticationBldr.authenticationEventPublisher(eventPublisher); AuthenticationManager authenticationManager = authenticationManager(); // [2.1] authenticationBuilder.parentAuthenticationManager(authenticationManager); authenticationBuilder.authenticationEventPublisher(eventPublisher); // 插入一些共享对象（如UserDetailService,ApplicationContext）用于下面HttpSecurity的构建 Map<Class<? extends Object>, Object> sharedObjects = createSharedObjects(); http = new HttpSecurity(objectPostProcessor, authenticationBuilder, sharedObjects); if (!disableDefaults) { // @formatter:off http .csrf().and() // [2.2] .addFilter(new WebAsyncManagerIntegrationFilter()) // [2.3] .exceptionHandling().and() // [2.4] .headers().and() // [2.5] .sessionManagement().and() // [2.6] .securityContext().and() // [2.7] .requestCache().and() // [2.8] .anonymous().and() // [2.9] .servletApi().and() // [2.10] .apply(new DefaultLoginPageConfigurer<>()).and() // [2.11] .logout(); // [2.12] // @formatter:on ClassLoader classLoader = this.context.getClassLoader(); List<AbstractHttpConfigurer> defaultHttpConfigurers = SpringFactoriesLoader.loadFactories(AbstractHttpConfigurer.class, classLoader); for (AbstractHttpConfigurer configurer : defaultHttpConfigurers) { http.apply(configurer); } } configure(http); return http; }
protected void configure(HttpSecurity http) throws Exception { logger.debug("Using default configure(HttpSecurity). If subclassed this will potentially override subclass configure(HttpSecurity)."); http .authorizeRequests() // [2.13] .anyRequest().authenticated() .and() .formLogin().and() // [2.14] .httpBasic(); // [2.15] }
[2.1] 这里实际上使用了配置类AuthenticationConfiguration Bean得到了一个AuthenticationManager，这个过程中，系统会自动配置这些认证对象：
ProviderManager -> AuthenticationManager
DaoAuthenticationProvider -> AuthenticationProvider
InMemoryUserDetailsManager -> UserDetailsService
User -> MutableUser -> MutableUserDetails -> UserDetails
其中，MutableUser代理了User对象及一个临时的password。系统会自动生成1个MutableUser，name为user（无ROLE）。
具体细节可以看（C）部分。
[2.2] 添加配置器CsrfConfigurer（包含过滤器CsrfFilter *）对CSRF的支持。
[2.3] 添加过滤器WebAsyncManagerIntegrationFilter。
[2.4] 添加配置器ExceptionHandlingConfigurer（包含过滤器ExceptionTranslationFilter *）对异常处理的支持。
[2.5] 添加配置器HeadersConfigurer（包含过滤器HeaderWriterFilter *）支持Adds the Security HTTP headers to the response。
[2.6] 添加配置器SessionManagementConfigurer（包含过滤器SessionManagementFilter *）支持session管理。
[2.7] 添加配置器SecurityContextConfigurer（包含过滤器SecurityContextPersistenceFilter *）支持对SecurityContextHolder的配置。
[2.8] 添加配置器RequestCacheConfigurer（包含过滤器RequestCacheAwareFilter *）支持request cache。
[2.9] 添加配置器AnonymousConfigurer（包含过滤器AnonymousAuthenticationFilter *）支持Anonymous authentication。
[2.10] 添加配置器ServletApiConfigurer（包含过滤器SecurityContextHolderAwareRequestFilter *）支持更多Servlet API。
[2.11] 添加配置器DefaultLoginPageConfigurer（包含过滤器DefaultLoginPageGeneratingFilter，DefaultLogoutPageGeneratingFilter *）支持默认的login和logout。
[2.12] 添加配置器LogoutConfigurer（包含过滤器LogoutFilter *）支持logout。
[2.13] 添加配置器ExpressionUrlAuthorizationConfigurer -> AbstractInterceptUrlConfigurer（包含过滤器FilterSecurityInterceptor *）支持URL based authorization。
[2.14] 添加配置器FormLoginConfigurer -> AbstractAuthenticationFilterConfigurer（包含过滤器UsernamePasswordAuthenticationFilter *）支持通过login认证。
[2.15] 添加配置器HttpBasicConfigurer（包含过滤器BasicAuthenticationFilter *）支持HTTP basic based authentication。
[*] 该过滤器在[1.2.3]中securityFilterChainBuilder.build()时通过调用该配置器的configure()方法把过滤器加到HttpSecurity中。
以上的15个过滤器就和章节2Spring Security(2)：过滤器链（filter chain）的介绍中的15个过滤器一一对应。
（C）构建AuthenticationManager及自动配置时自动创建认证对象
由[2.1]可知，Spring Security会自动创建一些认证对象。那么它们是怎么创建出来的呢？
在[2.1]中，调用了WebSecurityConfigurerAdapter.authenticationManager()方法。从下面的代码可以看到，由于我们并未配置自定义的AuthenticationManagerBuilder（变量名是localConfigureAuthenticationBldr），所以我们用注入的AuthenticationConfiguration，调用AuthenticationConfiguration的getAuthenticationManager()方法，得到了AuthenticationManager对象。
WebSecurityConfigurerAdapter.authenticationManager()：
private AuthenticationConfiguration authenticationConfiguration; /** * Gets the {@link AuthenticationManager} to use. The default strategy is if * {@link #configure(AuthenticationManagerBuilder)} method is overridden to use the * {@link AuthenticationManagerBuilder} that was passed in. Otherwise, autowire the * {@link AuthenticationManager} by type. * * @return the {@link AuthenticationManager} to use * @throws Exception */ protected AuthenticationManager authenticationManager() throws Exception { if (!authenticationManagerInitialized) { configure(localConfigureAuthenticationBldr); if (disableLocalConfigureAuthenticationBldr) { authenticationManager = authenticationConfiguration .getAuthenticationManager(); // execute here } else { authenticationManager = localConfigureAuthenticationBldr.build(); } authenticationManagerInitialized = true; } return authenticationManager; } @Autowired public void setAuthenticationConfiguration( AuthenticationConfiguration authenticationConfiguration) { this.authenticationConfiguration = authenticationConfiguration; }
AuthenticationConfiguration.getAuthenticationManager()：
public AuthenticationManager getAuthenticationManager() throws Exception { if (this.authenticationManagerInitialized) { return this.authenticationManager; } // [3.1] AuthenticationManagerBuilder authBuilder = authenticationManagerBuilder( this.objectPostProcessor, this.applicationContext); if (this.buildingAuthenticationManager.getAndSet(true)) { return new AuthenticationManagerDelegator(authBuilder); } // [3.2] for (GlobalAuthenticationConfigurerAdapter config : globalAuthConfigurers) { authBuilder.apply(config); } // [3.3] authenticationManager = authBuilder.build(); if (authenticationManager == null) { authenticationManager = getAuthenticationManagerBean(); } this.authenticationManagerInitialized = true; return authenticationManager; }
[3.1] 调用AuthenticationConfiguration.authenticationManagerBuilder()方法，使用了一个默认的AuthenticationManagerBuilder实现类DefaultPasswordEncoderAuthenticationManagerBuilder（同时这也是一个Bean）。
@Bean public AuthenticationManagerBuilder authenticationManagerBuilder( ObjectPostProcessor<Object> objectPostProcessor, ApplicationContext context) { LazyPasswordEncoder defaultPasswordEncoder = new LazyPasswordEncoder(context); AuthenticationEventPublisher authenticationEventPublisher = getBeanOrNull(context, AuthenticationEventPublisher.class); DefaultPasswordEncoderAuthenticationManagerBuilder result = new DefaultPasswordEncoderAuthenticationManagerBuilder(objectPostProcessor, defaultPasswordEncoder); if (authenticationEventPublisher != null) { result.authenticationEventPublisher(authenticationEventPublisher); } return result; }
[3.2] 这个globalAuthConfigurers其实就是AuthenticationConfiguration中声明的3个static bean。由于是static的，所以最早加载。
@Bean public static GlobalAuthenticationConfigurerAdapter enableGlobalAuthenticationAutowiredConfigurer( ApplicationContext context) {return new EnableGlobalAuthenticationAutowiredConfigurer(context); } @Bean public static InitializeUserDetailsBeanManagerConfigurer initializeUserDetailsBeanManagerConfigurer(ApplicationContext context) {return new InitializeUserDetailsBeanManagerConfigurer(context); } @Bean public static InitializeAuthenticationProviderBeanManagerConfigurer initializeAuthenticationProviderBeanManagerConfigurer(ApplicationContext context) {return new InitializeAuthenticationProviderBeanManagerConfigurer(context); }
[3.3] build()方法会调用AbstractConfiguredSecurityBuilder.doBuild()方法，最终会先后调用[3.2]的3个configurer的init()方法和configure()方法，及调用[3.1]DefaultPasswordEncoderAuthenticationManagerBuilder的父类AuthenticationManagerBuilder的performBuild()方法。
@Override protected final O doBuild() throws Exception { synchronized (configurers) { buildState = BuildState.INITIALIZING; beforeInit(); // 循环调用[3.2]的3个configurer的init()方法（有些可能没有） init(); buildState = BuildState.CONFIGURING; beforeConfigure(); // 循环调用[3.2]的3个configurer的configure()方法（有些可能没有） configure(); buildState = BuildState.BUILDING; // 调用[3.1]DefaultPasswordEncoderAuthenticationManagerBuilder的父类AuthenticationManagerBuilder的performBuild()方法 O result = performBuild(); buildState = BuildState.BUILT; return result; } }
通过调用这些方法自动生成了：
ProviderManager -> AuthenticationManager
DaoAuthenticationProvider -> AuthenticationProvider
InMemoryUserDetailsManager -> UserDetailsService
User -> MutableUser -> MutableUserDetails -> UserDetails
（C.1）User & InMemoryUserDetailsManager & DaoAuthenticationProvider：在InitializeUserDetailsBeanManagerConfigurer.config()中，及自动配置类UserDetailsServiceAutoConfiguration中创建
InitializeUserDetailsBeanManagerConfigurer：
@Override public void configure(AuthenticationManagerBuilder auth) throws Exception { if (auth.isConfigured()) { return; } // 如果使用了Spring Boot, 执行这一步时会使用自动配置， // 从UserDetailsServiceAutoConfiguration中Lazy load一个InMemoryUserDetailsManager UserDetailsService userDetailsService = getBeanOrNull( UserDetailsService.class); if (userDetailsService == null) { return; } PasswordEncoder passwordEncoder = getBeanOrNull(PasswordEncoder.class); UserDetailsPasswordService passwordManager = getBeanOrNull(UserDetailsPasswordService.class); // 创建DaoAuthenticationProvider，并把UserDetailsService放入其中 DaoAuthenticationProvider provider = new DaoAuthenticationProvider(); provider.setUserDetailsService(userDetailsService); if (passwordEncoder != null) { provider.setPasswordEncoder(passwordEncoder); } if (passwordManager != null) { provider.setUserDetailsPasswordService(passwordManager); } provider.afterPropertiesSet(); auth.authenticationProvider(provider); }
UserDetailsServiceAutoConfiguration：需要注意的是，Spring Bean容器中，如果同时没有AuthenticationManager，AuthenticationProvider，UserDetailsService时，该自动配置才会生效。（To also switch off the UserDetailsService configuration, you can add a bean of type UserDetailsService, AuthenticationProvider, or AuthenticationManager.）
@Configuration@ConditionalOnClass(AuthenticationManager.class)@ConditionalOnBean(ObjectPostProcessor.class)@ConditionalOnMissingBean({ AuthenticationManager.class, AuthenticationProvider.class, UserDetailsService.class })public class UserDetailsServiceAutoConfiguration { private static final String NOOP_PASSWORD_PREFIX = "{noop}"; private static final Pattern PASSWORD_ALGORITHM_PATTERN = Pattern .compile("^\\{.+}.*$"); private static final Log logger = LogFactory .getLog(UserDetailsServiceAutoConfiguration.class); @Bean @ConditionalOnMissingBean(type = "org.springframework.security.oauth2.client.registration.ClientRegistrationRepository") @Lazy public InMemoryUserDetailsManager inMemoryUserDetailsManager( SecurityProperties properties, ObjectProvider<PasswordEncoder> passwordEncoder) { SecurityProperties.User user = properties.getUser(); List<String> roles = user.getRoles(); return new InMemoryUserDetailsManager(User.withUsername(user.getName()) .password(getOrDeducePassword(user, passwordEncoder.getIfAvailable())) .roles(StringUtils.toStringArray(roles)).build()); } private String getOrDeducePassword(SecurityProperties.User user, PasswordEncoder encoder) { String password = user.getPassword(); if (user.isPasswordGenerated()) { logger.info(String.format("%n%nUsing generated security password: %s%n", user.getPassword())); } if (encoder != null || PASSWORD_ALGORITHM_PATTERN.matcher(password).matches()) { return password; } return NOOP_PASSWORD_PREFIX + password; }}
（C.2）ProviderManager ：在AuthenticationManagerBuilder.performBuild()中创建
@Override protected ProviderManager performBuild() throws Exception { if (!isConfigured()) { logger.debug("No authenticationProviders and no parentAuthenticationManager defined. Returning null."); return null; } ProviderManager providerManager = new ProviderManager(authenticationProviders, parentAuthenticationManager); if (eraseCredentials != null) { providerManager.setEraseCredentialsAfterAuthentication(eraseCredentials); } if (eventPublisher != null) { providerManager.setAuthenticationEventPublisher(eventPublisher); } providerManager = postProcess(providerManager); return providerManager; }
总结：
最后上两张类图，分别是SecurityBuilder和SecurityConfiger。流程实际上就是先调用Builder的add()方法或apply()方法添加和维护一个SecurityConfiger List。最后通过调用Builder的build()方法（实际上是AbstractConfiguredSecurityBuilder的doBuild()方法），调用SecurityConfiger的init()方法和configure()方法构建WebSecurity及过滤器链。