@Configuration
 @EnableWebSecurity
 public class MyWebSecurityConfiguration extends WebSecurityConfigurerAdapter {
        @Override
        public void configure(WebSecurity web) throws Exception {
                web.ignoring()
                // Spring Security should completely ignore URLs starting with /resources/
                                .antMatchers("/resources/**");
        }
        @Override
        protected void configure(HttpSecurity http) throws Exception {
                http.authorizeRequests().antMatchers("/public/**").permitAll().anyRequest()
                                .hasRole("USER").and()
                                // Possibly more configuration ...
                                .formLogin() // enable form based log in
                                // set permitAll for all URLs associated with Form Login
                                .permitAll();
        }
        @Override
        protected void configure(AuthenticationManagerBuilder auth) throws Exception {
                auth
                // enable in memory based authentication with a user named "user" and "admin"
                .inMemoryAuthentication().withUser("user").password("password").roles("USER")
                                .and().withUser("admin").password("password").roles("USER", "ADMIN");
        }
        // Possibly more overridden methods ...
 }

package org.springframework.boot.autoconfigure.security.servlet;
// 省略 imports 行
@Configuration
// 僅在存在 WebSecurityConfigurerAdapter bean 時(shí)該注解才有可能生效
// (最終生效與否要結(jié)合其他條件綜合考慮)
@ConditionalOnBean(WebSecurityConfigurerAdapter.class)
// 僅在不存在 springSecurityFilterChain 時(shí)該注解才有可能生效
// (最終生效與否要結(jié)合其他條件綜合考慮)
@ConditionalOnMissingBean(name = BeanIds.SPRING_SECURITY_FILTER_CHAIN)
// 僅在 Servlet 環(huán)境下該注解才有可能生效
// (最終生效與否要結(jié)合其他條件綜合考慮)
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)
@EnableWebSecurity // <====== 這里啟用了 Web 安全
public class WebSecurityEnablerConfiguration {
}

package org.springframework.security.config.annotation.web.configuration;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.security.config.annotation.authentication.configuration.EnableGlobalAuthentication;
import org.springframework.security.config.annotation.web.WebSecurityConfigurer;
/**
 *
 * @see WebSecurityConfigurer
 * @see WebSecurityConfigurerAdapter
 *
 * @author Rob Winch
 * @since 3.2
 */
@Retention(value = java.lang.annotation.RetentionPolicy.RUNTIME)
@Target(value = { java.lang.annotation.ElementType.TYPE })
@Documented
// 導(dǎo)入 WebSecurityConfiguration Web安全配置,Spring Web Mvc 有關(guān)安全的配置，OAuth2 有關(guān)安全的配置
@Import({ WebSecurityConfiguration.class,
		SpringWebMvcImportSelector.class,
		OAuth2ImportSelector.class })
// 啟用全局安全認(rèn)證機(jī)制		
@EnableGlobalAuthentication
@Configuration
public @interface EnableWebSecurity {
	/**
	 * Controls debugging support for Spring Security. Default is false.
	 * @return if true, enables debug support with Spring Security
	 */
	boolean debug() default false;
}