ShiroFilter

Shiro提供了与Web集成的支持，其通过一个ShiroFilter入口来拦截需要安全控制的URL，然后进行相应的控制，ShiroFilter类似于如Strut2/SpringMVC这种web框架的前端
其是安全控制的入口点，其负责读取配置（如ini配置文件），然后判断URL是否需要登录/权限等工作。

web.xml配置名字为shiroFilter的过滤器，这个bean去 shiro.in 或者shiro.xml配置文件中找

首先是在web.xml中配置DelegatingFilterProxy

    <!-- Shiro Security filter -->
    <filter>
        <filter-name>shiroFilter</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
        <async-supported>true</async-supported>
    </filter>
    <filter-mapping>
        <filter-name>shiroFilter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>REQUEST</dispatcher>
        <dispatcher>FORWARD</dispatcher>
    </filter-mapping>

配置好DelegatingFilterProxy后，下面只要再把ShiroFilter配置到Spring容器（此处为Spring的配置文件）即可：
(使用ShiroFilterFactoryBean创建shiroFilter)

 <bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean">
        <property name="securityManager" ref="securityManager" />
        <property name="loginUrl" value="/login" />
        <property name="successUrl" value="/" />
        <property name="filterChainDefinitions">
            <value>
                /favicon.ico = anon
                /assets/** = anon
                /jd/** = anon
                /uf/** = anon
                /upload/** = anon
                /upload-file = anon
                /api/code = anon
                /services/** = anon
                /api/login = anon
                /pushCall = anon
                /oc/** = anon
                /fl/** = anon
                /login = authc
                /logout = logout
                /api/v2/oc/user/login=anon
                /api/v2/oc/user/register=anon
                /api/v2/oc/user/checkPhoneCode=anon
                /api/v2/oc/user/reset/code=anon
                /api/v2/oc/user/reset/password=anon
                /api/v1/eam/**=mobile
                /api/v2/**=mobile
                /api/** = anon
                /** = user
            </value>
        </property>
         <!--  做拦截过滤  -->
        <property name="filters">
            <map>
                <entry key="mobile">
                    <bean class="com.xx.xx.shiro.filter.MobileAuthenticatingFilter"></bean>
                </entry>
            </map>
        </property>

    </bean>

使用了ShiroFilterFactoryBean来创建shiroFilter，这里用到了Spring中一种特殊的Bean——FactoryBean。当需要得到名为”shiroFilter“的bean时，会调用其getObject()来获取实例。下面我们通过分析ShiroFilterFactoryBean创建实例的过程来探究Shiro是如何实现安全拦截的：

ShiroFilterFactoryBean创建shiroFilter

public Object getObject() throws Exception { 
    if (instance == null) { 
        instance = createInstance(); 
    }
 return instance; 
 }

其中调用了createInstance()来创建实例：

    protected AbstractShiroFilter createInstance() throws Exception { 
        // 这里是通过FactoryBean注入的SecurityManager（必须）
        SecurityManager securityManager = getSecurityManager(); 
        if (securityManager == null) {
            String msg = "SecurityManager property must be set."; 
            throw new BeanInitializationException(msg); 
        } 
        if (!(securityManager instanceof WebSecurityManager)) { 
            String msg = "The security manager does not implement the WebSecurityManager interface."; throw new BeanInitializationException(msg);
        } 
        FilterChainManager manager = createFilterChainManager(); 
        PathMatchingFilterChainResolver chainResolver = new PathMatchingFilterChainResolver();
        chainResolver.setFilterChainManager(manager);
        return new SpringShiroFilter((WebSecurityManager) securityManager, chainResolver);
    }

可以看到创建SpringShiroFilter时用到了两个组件：SecurityManager和ChainResolver。

先有一个大体的了解，那么对于源码分析会有不少帮助。下面会对以上两个重要的组件进行分析，包括PathMatchingFilterChainResolver和FilterChainManager。首先贴一段ShiroFilter的在配置文件中的定义：

========> ="filterChainDefinitions">
 <value> /resources/** = anon 
/download/** = anon 
/special/unauthorized = anon
 /register = anon
/logout = logout 
/admin/** = roles[admin] 
/** = user >

PathMatchingFilterChainResolver和FilterChainManager的创建过程：

protected FilterChainManager createFilterChainManager() { 
 //默认使用的FilterChainManager是DefaultFilterChainManager
 DefaultFilterChainManager manager = new DefaultFilterChainManager(); 
// 将ShiroFilterFactoryBean配置的一些公共属性(上面配置的loginUrl,successUrl,unauthorizeUrl)应用到默认注册的filter上去 
for (Filter filter : defaultFilters.values()) { applyGlobalPropertiesIfNecessary(filter); 
} 
Filter filters = getFilters(); 
if (!CollectionUtils.isEmpty(filters)) {
 for (, Filter> entry : filters.entrySet()) { 
 Filter filter = entry.getValue(); applyGlobalPropertiesIfNecessary(filter);
  if (filter instanceof Nameable) {
} 
//将Filter添加到manager中去，可以看到对于Filter的管理是依赖于FilterChainManager的                         manager.addFilter(name, filter, false); 
} 
} 
 String> chains = getFilterChainDefinitionMap();
 for (String> entry : chains.entrySet()) { 
 String chainDefinition = entry.getValue();
manager.createChain(url, chainDefinition); } } 
return manager; }

待完成—-