讲解完http标签的解析过程，authentication-manager标签解析部分就很容易理解了
authentication-manager标签在spring的配置文件中的定义一般如下
1 <authentication-manager alias="authenticationManager"> 2 <authentication-provider user-service-ref="userDetailsManager"/> 3 </authentication-manager>
authentication-manager标签的解析类是：
org.springframework.security.config.authentication.AuthenticationManagerBeanDefinitionParser
具体解析方法parse的代码为
1 public BeanDefinition parse(Element element, ParserContext pc) {
2 Assert.state(!pc.getRegistry().containsBeanDefinition(BeanIds.AUTHENTICATION_MANAGER),
3 "AuthenticationManager has already been registered!");
4 pc.pushContainingComponent(new CompositeComponentDefinition(element.getTagName(), pc.extractSource(element)));
5 //构造ProviderManager的BeanDefinition
6 BeanDefinitionBuilder providerManagerBldr = BeanDefinitionBuilder.rootBeanDefinition(ProviderManager.class);
7 //获取alias属性
8 String alias = element.getAttribute(ATT_ALIAS);
9 //检查session-controller-ref属性，提示通过标签<concurrent-session-control>取代
10 checkForDeprecatedSessionControllerRef(element, pc);
11 List<BeanMetadataElement> providers = new ManagedList<BeanMetadataElement>();
12 NamespaceHandlerResolver resolver = pc.getReaderContext().getNamespaceHandlerResolver();
13 //获取authentication-manager的子节点
14 NodeList children = element.getChildNodes();
15 //循环节点，一般子节点主要是authentication-provider或者
16 //ldap-authentication-provider
17 for (int i = 0; i < children.getLength(); i++) {
18 Node node = children.item(i);
19 if (node instanceof Element) {
20 Element providerElt = (Element)node;
21 //判断子标签是否有ref属性，如果有，则直接将ref属性
22 //引用的bean id添加到providers集合中
23 if (StringUtils.hasText(providerElt.getAttribute(ATT_REF))) {
24 providers.add(new RuntimeBeanReference(providerElt.getAttribute(ATT_REF)));
25 } else {
26 //如果没有ref属性，则通过子标签的解析类完成标签解析
27 //如子标签：authentication-provider,解析过程在后面
28 BeanDefinition provider = resolver.resolve(providerElt.getNamespaceURI()).parse(providerElt, pc);
29 Assert.notNull(provider, "Parser for " + providerElt.getNodeName() + " returned a null bean definition");
30 String id = pc.getReaderContext().generateBeanName(provider);
31 //注册provider的BeanDefinition
32 pc.registerBeanComponent(new BeanComponentDefinition(provider, id));
33 //添加注册过的bean到provider集合中
34 providers.add(new RuntimeBeanReference(id));
35 }
36 }
37 }
38
39 if (providers.isEmpty()) {
40 providers.add(new RootBeanDefinition(NullAuthenticationProvider.class));
41 }
42
43 providerManagerBldr.addPropertyValue("providers", providers);
44 //添加默认的事件发布类
45 BeanDefinition publisher = new RootBeanDefinition(DefaultAuthenticationEventPublisher.class);
46 String id = pc.getReaderContext().generateBeanName(publisher);
47 pc.registerBeanComponent(new BeanComponentDefinition(publisher, id));
48 //将事件发布类的bean注入到ProviderManager的
49 //authenticationEventPublisher属性中
50 providerManagerBldr.addPropertyReference("authenticationEventPublisher", id);
51 //注册ProviderManager的bean
52 pc.registerBeanComponent(
53 new BeanComponentDefinition(providerManagerBldr.getBeanDefinition(), BeanIds.AUTHENTICATION_MANAGER));
54
55 if (StringUtils.hasText(alias)) {
56 pc.getRegistry().registerAlias(BeanIds.AUTHENTICATION_MANAGER, alias);
57 pc.getReaderContext().fireAliasRegistered(BeanIds.AUTHENTICATION_MANAGER, alias, pc.extractSource(element));
58 }
59
60 pc.popAndRegisterContainingComponent();
61
62 return null;
63 }
通过上面的代码片段，能够知道authentication-manager标签解析的步骤是
1.构造ProviderManager的BeanDefinition
2.循环authentication-manager的子标签，构造provider的BeanDefinition，并添加到providers集合中
3.将第2步的providers设置为ProviderManager的providers属性
4.构造异常事件发布类DefaultAuthenticationEventPublisher的BeanDefinition，并设置为ProviderManager的属性authenticationEventPublisher
5.通过registerBeanComponent方法完成bean的注册任务
authentication-provider标签的解析类为
org.springframework.security.config.authentication.AuthenticationProviderBeanDefinitionParser
1 public BeanDefinition parse(Element element, ParserContext parserContext) {
2 //首先构造DaoAuthenticationProvider的BeanDefinition
3 RootBeanDefinition authProvider = new RootBeanDefinition(DaoAuthenticationProvider.class);
4 authProvider.setSource(parserContext.extractSource(element));
5 //获取password-encoder子标签
6 Element passwordEncoderElt = DomUtils.getChildElementByTagName(element, Elements.PASSWORD_ENCODER);
7
8 if (passwordEncoderElt != null) {
9 //如果有password-encoder子标签，把解析任务交给
10 //PasswordEncoderParser完成
11 PasswordEncoderParser pep = new PasswordEncoderParser(passwordEncoderElt, parserContext);
12 authProvider.getPropertyValues().addPropertyValue("passwordEncoder", pep.getPasswordEncoder());
13 //如果有salt-source标签，将值注入到saltSource属性中
14 if (pep.getSaltSource() != null) {
15 authProvider.getPropertyValues().addPropertyValue("saltSource", pep.getSaltSource());
16 }
17 }
18 //下面获取子标签user-service、jdbc-user-service、ldap-user-service
19 Element userServiceElt = DomUtils.getChildElementByTagName(element, Elements.USER_SERVICE);
20 Element jdbcUserServiceElt = DomUtils.getChildElementByTagName(element, Elements.JDBC_USER_SERVICE);
21 Element ldapUserServiceElt = DomUtils.getChildElementByTagName(element, Elements.LDAP_USER_SERVICE);
22
23 String ref = element.getAttribute(ATT_USER_DETAILS_REF);
24
25 if (StringUtils.hasText(ref)) {
26 if (userServiceElt != null || jdbcUserServiceElt != null || ldapUserServiceElt != null) {
27 parserContext.getReaderContext().error("The " + ATT_USER_DETAILS_REF + " attribute cannot be used in combination with child" +
28 "elements ‘" + Elements.USER_SERVICE + "‘, ‘" + Elements.JDBC_USER_SERVICE + "‘ or ‘" +
29 Elements.LDAP_USER_SERVICE + "‘", element);
30 }
31 } else {
32 // Use the child elements to create the UserDetailsService
33 AbstractUserDetailsServiceBeanDefinitionParser parser = null;
34 Element elt = null;
35 //下面的if语句，主要是根据子标签的不同，选择子标签对应的解析器处理
36 if (userServiceElt != null) {
37 elt = userServiceElt;
38 parser = new UserServiceBeanDefinitionParser();
39 } else if (jdbcUserServiceElt != null) {
40 elt = jdbcUserServiceElt;
41 parser = new JdbcUserServiceBeanDefinitionParser();
42 } else if (ldapUserServiceElt != null) {
43 elt = ldapUserServiceElt;
44 parser = new LdapUserServiceBeanDefinitionParser();
45 } else {
46 parserContext.getReaderContext().error("A user-service is required", element);
47 }
48
49 parser.parse(elt, parserContext);
50 ref = parser.getId();
51 String cacheRef = elt.getAttribute(AbstractUserDetailsServiceBeanDefinitionParser.CACHE_REF);
52
53 if (StringUtils.hasText(cacheRef)) {
54 authProvider.getPropertyValues().addPropertyValue("userCache", new RuntimeBeanReference(cacheRef));
55 }
56 }
57 //将解析后的bean id注入到userDetailsService属性中
58 authProvider.getPropertyValues().addPropertyValue("userDetailsService", new RuntimeBeanReference(ref));
59 return authProvider;
60 }
如果学习过acegi的配置，应该知道，acegi有这么一段配置
1 <bean id="authenticationManager" class="org.acegisecurity.providers.ProviderManager"> 2 <property name="providers"> 3 <list> 4 <ref local="daoAuthenticationProvider"/> 5 <ref local="anonymousAuthenticationProvider"/> 6 </list> 7 </property> 8 </bean>
实际上authentication-manager标签所要达到的目标就是构造上面的bean。其中anonymousAuthenticationProvider是在http解析过程添加的。
其实可以完全像acegi那样自定义每个bean。
1 <authentication-manager alias="authenticationManager"> 2 <authentication-provider user-service-ref="userDetailsManager"/> 3 </authentication-manager>
上面的标签如果用bean来定义，则可以完全由下面的xml来替代。
1 <bean id="org.springframework.security.authenticationManager" class="org.springframework.security.authentication.ProviderManager"> 2 <property name="authenticationEventPublisher" ref="defaultAuthenticationEventPublisher"></property> 3 <property name="providers"> 4 <list> 5 <ref local="daoAuthenticationProvider"/> 6 <ref local="anonymousAuthenticationProvider"/> 7 </list> 8 </property> 9 </bean> 10 11 <bean id="defaultAuthenticationEventPublisher" class="org.springframework.security.authentication.DefaultAuthenticationEventPublisher"></bean> 12 13 <bean id="anonymousAuthenticationProvider" class="org.springframework.security.authentication.AnonymousAuthenticationProvider"> 14 <property name="key"><value>work</value></property> 15 </bean> 16 17 <bean id="daoAuthenticationProvider" class="org.springframework.security.authentication.dao.DaoAuthenticationProvider"> 18 <property name="userDetailsService" ref="userDetailsManager"></property> 19 </bean>
需要注意的是anonymousAuthenticationProvider的bean中，需要增加key属性。如果采用authentication-manager标签的方式，key虽然没有定义，在增加AnonymousAuthenticationFilter过滤器中，是通过java.security.SecureRandom.nextLong()来生成的。
显而易见，如果采用bean的方式来定义，非常复杂，而且需要了解底层的组装过程才行，不过能够提高更大的扩展性。采用authentication-manager标签的方式，很简洁，只需要提供UserDetailsService即可。
时间： 2024-10-14 03:23:04