接着上节的讲，在添加了@EnableWebSecurity注解后，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。
我们来看一下WebSecurityConfigurerAdapter中哪些方法可以重写，需要重写。
（1）WebSecurity
默认是一个空方法，一般也不会再重写。
public void configure(WebSecurity web) throws Exception { }
（2）HttpSecurity
默认的父类代码默认任何request都需要认证，使用默认的login page基于表单认证，使用HTTP基本认证。
protected void configure(HttpSecurity http) throws Exception {
http
.authorizeRequests()
.anyRequest().authenticated()
.and()
.formLogin().and()
.httpBasic();
}
下面是一些自定义写法。
@Override
protected void configure(HttpSecurity http) throws Exception {
//@formatter:off
http.authorizeRequests()
// all users have access to these urls
.antMatchers("/resources/**", "/signup", "/about").permitAll()
// Any URL that starts with "/admin/" will be restricted to users who have the role "ROLE_ADMIN"
.antMatchers("/admin/**").hasRole("ADMIN")
// Any URL that starts with "/db/" requires the user to have both "ROLE_ADMIN" and "ROLE_DBA"
.antMatchers("/db/**").access("hasRole('ADMIN') and hasRole('DBA')")
// Any URL that starts with "/group_a/" requires the user to have both "ROLE_ADMIN" or "ROLE_GROUP_A"
.antMatchers("/admin/**").hasAnyRole("ADMIN", "GROUP_A")
// Any URL that has not already been matched on only requires that the user be authenticated
.anyRequest().authenticated()
.and().formLogin()
// all users have access to custom login page
.loginPage("/login").permitAll()
.and().logout()
// customize logout url
.logoutUrl("/my/logout")
// customize logout success url
.logoutSuccessUrl("/my/index")
// specify a custom LogoutSuccessHandler. If this is specified, logoutSuccessUrl() is ignored
.logoutSuccessHandler(logoutSuccessHandler)
// invalidate the HttpSession at the time of logout. This is true by default
.invalidateHttpSession(true)
// Adds a LogoutHandler. SecurityContextLogoutHandler is added as the last LogoutHandler by default
.addLogoutHandler(logoutHandler)
// Allows specifying the names of cookies to be removed on logout success
.deleteCookies()
.and().rememberMe()
// Add remember me function and valid date.
.key("uniqueAndSecret")
.tokenValiditySeconds(60 * 60 * 24 * 7);
//@formatter:on
}
（3）AuthenticationManagerBuilder
默认是这样写的：
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
this.disableLocalConfigureAuthenticationBldr = true;
}
由上一节分析可知，它其实默认使用DefaultPasswordEncoderAuthenticationManagerBuilder这个Builder及自动配置的UserDetails和UserDetailsService。
protected AuthenticationManager authenticationManager() throws Exception {
if (!authenticationManagerInitialized) {
// [1]如果覆盖configure()方法，则disableLocalConfigureAuthenticationBldr为false
// [2]如果是默认的configure()方法，disableLocalConfigureAuthenticationBldr还是true
configure(localConfigureAuthenticationBldr);
if (disableLocalConfigureAuthenticationBldr) {
authenticationManager = authenticationConfiguration
.getAuthenticationManager(); // [2]
}
else {
authenticationManager = localConfigureAuthenticationBldr.build(); // [1]
}
authenticationManagerInitialized = true;
}
return authenticationManager;
}
如果被覆盖，虽然还是使用的DefaultPasswordEncoderAuthenticationManagerBuilder，但是我们可以使用UserDetailsManagerConfigurer（的两个子类InMemoryUserDetailsManagerConfigurer，JdbcUserDetailsManagerConfigurer）来构建UserDetailsService及UserDetails。以InMemoryUserDetailsManagerConfigurer为例，下面是自定义的写法。
@Bean
PasswordEncoder passwordEncoder() {
return PasswordEncoderFactories.createDelegatingPasswordEncoder();
}
@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
//@formatter:off
// returns InMemoryUserDetailsManagerConfigurer
PasswordEncoder encoder = new BCryptPasswordEncoder();
auth.inMemoryAuthentication()
// create a UserDetailsBuilder and add to userBuilders
.withUser("user").password("{bcrypt}" + encoder.encode("pass")).roles("USER")
// returns InMemoryUserDetailsManagerConfigurer
.and()
// create a UserDetailsBuilder again and add to userBuilders
.withUser("admin").password("{bcrypt}" + encoder.encode("pass")).roles("USER", "ADMIN");
//@formatter:on
}
[注] 框架要求密码必须加密，所以这里加了有关password encode的支持。
那么这段代码如何生成UserDetailsService及UserDetails的呢？流程如下：
[1] 调用AuthenticationManagerBuilder的inMemoryAuthentication()方法创建InMemoryUserDetailsManagerConfigurer，调用InMemoryUserDetailsManagerConfigurer的构造器时则会创建InMemoryUserDetailsManager（即UserDetailsService的实现类），最终经过层层父类（InMemoryUserDetailsManagerConfigurer -> UserDetailsManagerConfigurer -> UserDetailsServiceConfigurer -> AbstractDaoAuthenticationConfigurer）设定到AbstractDaoAuthenticationConfigurer中。
public InMemoryUserDetailsManagerConfigurer<AuthenticationManagerBuilder> inMemoryAuthentication()
throws Exception {
return apply(new InMemoryUserDetailsManagerConfigurer<>());
}
public InMemoryUserDetailsManagerConfigurer() {
super(new InMemoryUserDetailsManager(new ArrayList<>()));
}
protected AbstractDaoAuthenticationConfigurer(U userDetailsService) {
this.userDetailsService = userDetailsService;
provider.setUserDetailsService(userDetailsService);
if (userDetailsService instanceof UserDetailsPasswordService) {
this.provider.setUserDetailsPasswordService((UserDetailsPasswordService) userDetailsService);
}
}
[2] 调用AuthenticationManagerBuilder的apply()方法设定defaultUserDetailsService为[1]的InMemoryUserDetailsManager并且把[1]的InMemoryUserDetailsManagerConfigurer加到父类AbstractConfiguredSecurityBuilder的configurers list中
private <C extends UserDetailsAwareConfigurer<AuthenticationManagerBuilder, ? extends UserDetailsService>> C apply(
C configurer) throws Exception {
this.defaultUserDetailsService = configurer.getUserDetailsService();
return (C) super.apply(configurer);
}
[3] 调用InMemoryUserDetailsManagerConfigurer的父类UserDetailsManagerConfigurer的withUser()方法生成多个UserDetailsBuilder放在userBuilders list中
public final UserDetailsBuilder withUser(String username) {
UserDetailsBuilder userBuilder = new UserDetailsBuilder((C) this);
userBuilder.username(username);
this.userBuilders.add(userBuilder);
return userBuilder;
}
[4] 当调用DefaultPasswordEncoderAuthenticationManagerBuilder的build()方法时，则会调用
[4.1] 调用UserDetailsServiceConfigurer的configure()方法
@Override
public void configure(B builder) throws Exception {
initUserDetailsService();
super.configure(builder);
}
[4.2] 调用UserDetailsManagerConfigurer的initUserDetailsService()方法通过[3]的userBuilders创建User对象（UserDetails的实现类），并且从[1]中的AbstractDaoAuthenticationConfigurer获取UserDetailsService，并把UserDetails放到UserDetailsService中。
@Override
protected void initUserDetailsService() throws Exception {
for (UserDetailsBuilder userBuilder : userBuilders) {
getUserDetailsService().createUser(userBuilder.build());
}
for (UserDetails userDetails : this.users) {
getUserDetailsService().createUser(userDetails);
}
}
下面是一些自定义写法：
@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
//@formatter:off
// returns InMemoryUserDetailsManagerConfigurer
auth.inMemoryAuthentication()
// create a UserBuilder and add to userBuilders
.withUser("user").password("password").roles("USER")
// returns InMemoryUserDetailsManagerConfigurer
.and()
// create a UserBuilder again and add to userBuilders
.withUser("admin").password("password").roles("USER", "ADMIN");
//@formatter:on
}
（4）authenticationManagerBean()
我们覆盖了configure(AuthenticationManagerBuilder auth)后，我们使用了AuthenticationManagerBuilder 的实现类DefaultPasswordEncoderAuthenticationManagerBuilder，通过InMemoryUserDetailsManagerConfigurer创建自己的UserDetailsService的实现类InMemoryUserDetailsManager及User，系统还会默认给我们创建AuthenticationProvider的实现类DaoAuthenticationProvider。但是我们发现，这些对象并不是Spring Bean。所以我们可以通过覆盖该方法并且声明为一个Bean，这样就可以在项目中注入并使用这个Bean了。
@Bean(name = "myAuthenticationManager")
@Override
public AuthenticationManager authenticationManagerBean() throws Exception {
return super.authenticationManagerBean();
}
通过父类的源码可以看到，实际上在调用时，创建了一个AuthenticationManager代理。
public AuthenticationManager authenticationManagerBean() throws Exception {
return new AuthenticationManagerDelegator(authenticationBuilder, context);
}
（5）userDetailsServiceBean()
和（4）类似，Override this method to expose a UserDetailsService created from configure(AuthenticationManagerBuilder) as a bean. In general only thefollowing override should be done of this method：
@Bean(name = "myUserDetailsService")
@Override
public UserDetailsService userDetailsServiceBean() throws Exception {
return super.userDetailsServiceBean();
}
（6） UserDetailsService