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**：
@EnableWebSecurity
public 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)
@EnableWebSecurity
public 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
*/
@Configuration
public 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
（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）:
@Configuration
public 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。
@EnableWebSecurity
public 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。
