SpringSecurity的WebSecurity和HttpSecurity_websecurityconfig securityfilterchain

前言：WebSecurity和HttpSecurity本质上都是SecurityBuilder.需要通过SecurityConfigurer来配置。

//摘自AbstractConfiguredSecurityBuilder  
protected final O doBuild() throws Exception {
			init();
			configure();
			O result = performBuild();
			return result;
		}
	}
  
  private void init() throws Exception {
		for (SecurityConfigurer<O, B> configurer : configurers) {
			configurer.init((B) this);
		}
	}
 
  private void configure() throws Exception {
		for (SecurityConfigurer<O, B> configurer : configurers) {
			configurer.configure((B) this);
		}
  }

故事开始！一切都要从WebSecurityConfiguration讲起。

1.该方法把所有的WebSecurityConfigurer，都加到WebSecurity中。

@Autowired(required = false)
public void setFilterChainProxySecurityConfigurer(
    ObjectPostProcessor<Object> objectPostProcessor,
    List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers)
			throws Exception {
        ......
		for (SecurityConfigurer<Filter, WebSecurity> webSecurityConfigurer : webSecurityConfigurers) {
			webSecurity.apply(webSecurityConfigurer);
		}
		this.webSecurityConfigurers = webSecurityConfigurers;
}

2.WebSecurity完成使命（生成过滤器），此时会调用WebSecurityConfigure的init()和configure()方法。

public Filter springSecurityFilterChain() throws Exception {
		...
		return webSecurity.build();
	}

好了，现在把目光转移到WebSecurityConfigurerAdapter的init()。

public void init(final WebSecurity web) throws Exception {
		final HttpSecurity http = getHttp();
		web.addSecurityFilterChainBuilder(http);
}

这个方法很重要。1.生成了HttpSecurity。2.把HttpSecurity和WebSecurity联系到了一起。

我们先来看看HttpSecurity是如何生成的。

protected final HttpSecurity getHttp() throws Exception {
		if (http != null) {
			return http;
		}
        ...
		http = new HttpSecurity(objectPostProcessor, authenticationBuilder,
				sharedObjects);
        ...
		configure(http);
		return http;
	}

调用了WebSecurityConfigurerAdapter.configure(HttpSecurity)方法。注意：WebSecurityConfigurerAdapter还有一个configure(WebSecurity)方法，不要混淆。

再来看看WebSecurity是如何使用HttpSecurity的。

摘自WebSecurity
protected Filter performBuild() throws Exception {
        ...
		for (SecurityBuilder<? extends SecurityFilterChain> securityFilterChainBuilder : securityFilterChainBuilders) {
			securityFilterChains.add(securityFilterChainBuilder.build());
		}
		FilterChainProxy filterChainProxy = new FilterChainProxy(securityFilterChains);
		Filter result = filterChainProxy;
		return result;
	}

可以看到调用了HttpSecurity的build(),此方法又会调用HttpSecurity内的SecurityConfigurer来完成对它的配置。