Shiro源码分析-ShiroFilterFactoryBean 2020-04-29

配置代码

@Bean
    public ShiroFilterFactoryBean (@Qualifier("securityManager") SecurityManager securityManager) {
        log.info("进入shiroFilter");
        ShiroFilterFactoryBean shiroFilterFactoryBean = new ShiroFilterFactoryBean();
        shiroFilterFactoryBean.setSecurityManager(securityManager);
        // 拦截器
        Map<String, String> filterChainDefinitionMap = new LinkedHashMap<>();
        filterChainDefinitionMap.put("/static/**", "anon");
        filterChainDefinitionMap.put("/user/login", "anon");
        filterChainDefinitionMap.put("/user/logout", "logout");
        // 根据用户的角色赋予相应的权限
        // filterChainDefinitionMap.put("/add", "roles[admin]");
        // filterChainDefinitionMap.put("/delete", "roles[admin]");
        // filterChainDefinitionMap.put("/delete", "roles[author]");
        filterChainDefinitionMap.put("/addPermission", "roles[author]");
        filterChainDefinitionMap.put("/add", "perms[user:add]");
        filterChainDefinitionMap.put("/delete", "perms[user:delete]");
        filterChainDefinitionMap.put("/userList", "perms[user:list]");
        // 匹配所有的路径
        // 通过Map集合组成了一个拦截器链 ，自顶向下过滤，一旦匹配，则不再执行下面的过滤
        // 如果下面的定义与上面冲突，那按照了谁先定义谁说了算
        // 一定要配置在最后
        filterChainDefinitionMap.put("/**", "authc");
        // 将拦截器链设置到shiro中
      shiroFilterFactoryBean.setFilterChainDefinitionMap(filterChainDefinitionMap);
        // 如果不设置默认会自动寻找Web工程根目录下的"/login.html"页面
        shiroFilterFactoryBean.setLoginUrl("/login");
        // 登录成功后要跳转的链接
        shiroFilterFactoryBean.setSuccessUrl("/index");
        // 未授权页面
        shiroFilterFactoryBean.setUnauthorizedUrl("/403");
        return shiroFilterFactoryBean;
    }

继承链

ShiroFilterFactoryBean实现了FactoryBean和BeanPostProcessor接口

1、BeanPostProcessor接口的实现

/**
     * Inspects a bean, and if it implements the {@link Filter} interface, automatically adds that filter
     * instance to the internal {@link #setFilters(java.util.Map) filters map} that will be referenced
     * later during filter chain construction.
     */
// 检查一个bean,如果它实现了filter接口，自动将该过滤器添加到内部filters map中,稍后在过滤器链的构建过程中再引用该实例(后面第4点createFilterChainManager )
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof Filter) {
            log.debug("Found filter chain candidate filter ‘{}‘", beanName);
            Filter filter = (Filter) bean;
            // 应用全局配置
            applyGlobalPropertiesIfNecessary(filter);
            // 将在Spring中注册(而不是在ShiroFilterFactoryBean中配置的)的Filter并入.
            // 这里面就牵扯出一个有趣的问题 : FactoryBean<T>接口的getObject方法和     BeanPostProcessor接口的postProcessBeforeInitialization的执行先后顺序？
            // （为了保证不遗漏Filter, 我们可以猜测后者必须优先于前者。）
            // 上面这个括号里面的参考下面博客的说法有一点要注意的是，打断点调试确实是postProcessBeforeInitialization先进去的但是并没有进去找到任何的filter，因为我是注解提供的filterMap，所以是在执行createFilterChainManager的时候先查找default的filter再添加我们在config类中传进去的flterMap解析filter到filterChainManager中。我猜测如果是有xml配置的话，应该是postProcessBeforeInitialization最先读取xml配置中的filter的
            // 这里先记录一下吧
            getFilters().put(beanName, filter);
        } else {
            log.trace("Ignoring non-Filter bean ‘{}‘", beanName);
        }
        return bean;
    }

2、FactoryBean的接口实现

FactoryBean说白了就是一个工厂类的bean可以生产我们自己定义的bean并进行一些装饰

可以在这里看一下BeanFactory和FactoryBean的区别https://blog.csdn.net/weixin_38361347/article/details/92852611

public Object getObject() throws Exception {
        if (instance == null) {
            instance = createInstance();
        }
        return instance;
    }
 public Class getObjectType() {
        return SpringShiroFilter.class;
    }

Shiro源码分析-ShiroFilterFactoryBean

显然我们的ShiroFilterFactoryBean创建的是SpringShiroFilter的实例

3、ShiroFilterFactoryBean.createInstance 方法

/**
     * This implementation:
     * <ol>
     * <li>Ensures the required {@link #setSecurityManager(org.apache.shiro.mgt.SecurityManager) securityManager}
     * property has been set</li>
     * <li>{@link #createFilterChainManager() Creates} a {@link FilterChainManager} instance that reflects the
     * configured {@link #setFilters(java.util.Map) filters} and
     * {@link #setFilterChainDefinitionMap(java.util.Map) filter chain definitions}</li>
     * <li>Wraps the FilterChainManager with a suitable
     * {@link org.apache.shiro.web.filter.mgt.FilterChainResolver FilterChainResolver} since the Shiro Filter
     * implementations do not know of {@code FilterChainManager}s</li>
     * <li>Sets both the {@code SecurityManager} and {@code FilterChainResolver} instances on a new Shiro Filter
     * instance and returns that filter instance.</li>
     * </ol>
     *
     * @return a new Shiro Filter reflecting any configured filters and filter chain definitions.
     * @throws Exception if there is a problem creating the AbstractShiroFilter instance.
     */
    protected AbstractShiroFilter createInstance() throws Exception {
?
        log.debug("Creating Shiro Filter instance.");
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        SecurityManager securityManager = getSecurityManager();
        // 创建实例之前必须设置securityManager
        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);
        }
        //看下面分析4
        FilterChainManager manager = createFilterChainManager();
?
        //Expose the constructed FilterChainManager by first wrapping it in a
        //FilterChainResolver implementation. The AbstractShiroFilter implementations
        //do not know about FilterChainManagers - only resolvers:
        //写死为PathMatchingFilterChainResolver
        PathMatchingFilterChainResolver chainResolver = new PathMatchingFilterChainResolver();
        chainResolver.setFilterChainManager(manager);
?
        //Now create a concrete ShiroFilter instance and apply the acquired SecurityManager and built
        //FilterChainResolver.  It doesn‘t matter that the instance is an anonymous inner class
        //here - we‘re just using it because it is a concrete AbstractShiroFilter instance that accepts
        //injection of the SecurityManager and FilterChainResolver:
        //构造SpringShiroFilter实例,由Spring管理
        return new SpringShiroFilter((WebSecurityManager) securityManager, chainResolver);
    }

翻译一下上面的注释

实现创建这个实例之前：

1、必须确保SecurityManager属性已经设置了

2、创建一个FilterChainManager实例，该实例反映了我们配置的相关过滤内容filterChainDefinitionMap

3、用合适的方法包装FilterChainManager

4、因为shiro filter 实例不能感知到FilterChainManager，我们需要给它配置解析器FilterChainResolver

5、一个新的Shiro过滤器，它反映了所有已配置的过滤器和过滤器链定义。

4、ShiroFilterFactoryBean.createFilterChainManager 方法

看看PathMatchingFilterChainResolver和FilterChainManager的创建过程：

protected FilterChainManager createFilterChainManager() {
        // 这个构造函数中会将shiro默认的Filter添加到FilterChainManager中.
        // 点进去查看shiro的默认filter有哪些，见后面分析5
        DefaultFilterChainManager manager = new DefaultFilterChainManager();
        Map<String, Filter> defaultFilters = manager.getFilters();
        // 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);
        }
        //Apply the acquired and/or configured filters:
        // 然后再将用户配置的Filter并入; 所以如果用户配置了与上面同名的Filter, 则会进行覆盖操作
        // 此处的getFilters();获取的是当前实例的filters属性，这个是属性值在创建默认的DefaultFilterChainManager的时候add进去的默认filter，以及在web.xml中自定义的filter(由postProcessBeforeInitialization注入)
        Map<String, Filter> filters = getFilters();
        if (!CollectionUtils.isEmpty(filters)) {
            for (Map.Entry<String, Filter> entry : filters.entrySet()) {
                String name = entry.getKey();
                Filter filter = entry.getValue();
                applyGlobalPropertiesIfNecessary(filter);
                if (filter instanceof Nameable) {
                    ((Nameable) filter).setName(name);
                }
                //‘init‘ argument is false, since Spring-configured filters should be initialized
                // in Spring (i.e. ‘init-method=blah‘) or implement InitializingBean:
                // spring会处理初始化问题, 所以shiro就不负责初始化了
                manager.addFilter(name, filter, false);
            }
        }
        //build up the chains:
        // 这里将处理用户配置的ShiroFilterFactoryBean.filterChainDefinitions属性
        Map<String, String> chains = getFilterChainDefinitionMap();
        if (!CollectionUtils.isEmpty(chains)) {
            for (Map.Entry<String, String> entry : chains.entrySet()) {
                String url = entry.getKey();
                String chainDefinition = entry.getValue();
                // 见下面分析7
                manager.createChain(url, chainDefinition);
            }
        }
        return manager;
    }

5、shiro的DefaultFilterChainManager()

有必要来看看DefaultFilterChainManager的源码，分析一下上面调用到的方法。先来看看他的几个重要的属性：

其中filterConfig仅在初始化Filter时有效，而我们自定义的Filter都不是init的，所以该属性可以暂时忽略（）。而后面两张map就重要了：filters中缓存了所有添加的filter，filterChains则缓存了所有的filterChain。其中前者的key是filter name，value是Filter。而后者的key是chain name，value是NamedFilterList。有的童鞋可能会问NamedFilterList是怎么样的结构呢，你可以把它当成List<Filter>，这样就好理解了

private FilterConfig filterConfig;
 private Map<String, Filter> filters; //pool of filters available for creating chains
 private Map<String, NamedFilterList> filterChains; //key: chain name, value: chain
DefaultFilterChainManager manager = new DefaultFilterChainManager();
// DefaultFilterChainManager构造函数
public DefaultFilterChainManager() {
        this.addDefaultFilters(false);
    }
?
protected void addDefaultFilters(boolean init) {
        // shiro的DefaultFilter是一个枚举类，包含下面的11种启动时默认加载的filter
        DefaultFilter[] var2 = DefaultFilter.values();
        int var3 = var2.length;
        // 遍历
        for(int var4 = 0; var4 < var3; ++var4) {
          DefaultFilter defaultFilter = var2[var4];
          // 把filter添加到manager中，不需要初始化，由Spring来完成
          this.addFilter(defaultFilter.name(), defaultFilter.newInstance(), init, false);
        }
    }
?
public enum DefaultFilter {
    anon(AnonymousFilter.class),
    authc(FormAuthenticationFilter.class),
    authcBasic(BasicHttpAuthenticationFilter.class),
    logout(LogoutFilter.class),
    noSessionCreation(NoSessionCreationFilter.class),
    perms(PermissionsAuthorizationFilter.class),
    port(PortFilter.class),
    rest(HttpMethodPermissionFilter.class),
    roles(RolesAuthorizationFilter.class),
    ssl(SslFilter.class),
    user(UserFilter.class);
}

6、filterChainDefinitionMap

在分析createChain前先 shiro是如何处理上面spring-shiro.xml中用户配置的 ShiroFilterFactoryBean.filterChainDefinitions属性的

下面的是使用xml配置时shiro读取配置文件的实现

//---------- ShiroFilterFactoryBean.setFilterChainDefinitions方法
public void setFilterChainDefinitions(String definitions) {
    // 使用Ini类来解析用户配置的信息
    Ini ini = new Ini();
    ini.load(definitions);
    //did they explicitly state a ‘urls‘ section?  Not necessary, but just in case:
    Ini.Section section = ini.getSection(IniFilterChainResolverFactory.URLS);
    if (CollectionUtils.isEmpty(section)) {
        //no urls section.  Since this _is_ a urls chain definition property, just assume the
        //default section contains only the definitions:
        section = ini.getSection(Ini.DEFAULT_SECTION_NAME);
    }
    // 将解析出来的结果赋值给ShiroFilterFactoryBean的filterChainDefinitionMap字段
    setFilterChainDefinitionMap(section);
}

还有另外一种方式，在代码中使用注解的配置方式，直接用代码给filterChainDefinitionMap赋值即可，即本文最开头的配置代码中的方式

 // 将拦截器链设置到shiro中  shiroFilterFactoryBean.setFilterChainDefinitionMap(filterChainDefinitionMap);

7、DefaultFilterChainManager.createChain方法

这个方法执行完之后，用户配置的url权限校验（即ShiroFilterFactoryBean的filterChainDefinitions参数）就算是解析到位了（存放到了DefaultFilterChainManager的filterChains参数中）。

public void createChain(String chainName, String chainDefinition) {
        // 以上面配置的filterChainDefinitions参数举例:    
        // 参数chainName形如 /admin/list**
        // 参数chainDefinition形如 authc,perms[admin:manage]
        if (!StringUtils.hasText(chainName)) {
            throw new NullPointerException("chainName cannot be null or empty.");
        }
        if (!StringUtils.hasText(chainDefinition)) {
            throw new NullPointerException("chainDefinition cannot be null or empty.");
        }
        if (log.isDebugEnabled()) {
            log.debug("Creating chain [" + chainName + "] from String definition [" + chainDefinition + "]");
        }
?
        //parse the value by tokenizing it to get the resulting filter-specific config entries
        //
        //e.g. for a value of
        //
        //     "authc, roles[admin,user], perms[file:edit]"
        //
        // the resulting token array would equal
        //
        //     { "authc", "roles[admin,user]", "perms[file:edit]" }
        //以上我们就可以看出我们所配置的ShiroFilterFactoryBean的filterChainDefinitions里的 每一行 会在这里被完整解析
        String[] filterTokens = splitChainDefinition(chainDefinition);
?
        //each token is specific to each filter.
        //strip the name and extract any filter-specific config between brackets [ ]
        for (String token : filterTokens) {
            /* toNameConfigPair的解析结果参见下面这个，摘选自官方
        Input               Result 
        
        foo                 returned[0] == foo
                            returned[1] == null 
                            
        foo[bar, baz]       returned[0] == foo
                            returned[1] == bar, baz 
        */
            String[] nameConfigPair = toNameConfigPair(token);
            //now we have the filter name, path and (possibly null) path-specific config.  Let‘s apply them:
            // 见分析8
            addToChain(chainName, nameConfigPair[0], nameConfigPair[1]);
        }
    }

8、DefaultFilterChainManager.addToChain方法

public void addToChain(String chainName, String filterName, String chainSpecificFilterConfig) {
        if (!StringUtils.hasText(chainName)) {
            throw new IllegalArgumentException("chainName cannot be null or empty.");
        }
        // 如果用户没有配置该filter, 则直接抛出的异常
        Filter filter = getFilter(filterName);
        if (filter == null) {
            throw new IllegalArgumentException("There is no filter with name ‘" + filterName +
                    "‘ to apply to chain [" + chainName + "] in the pool of available Filters.  Ensure a " +
                    "filter with that name/path has first been registered with the addFilter method(s).");
        }
        // 保存用户配置的url与filter之间的映射关系,注册到filter中
        applyChainConfig(chainName, filter, chainSpecificFilterConfig);
        // chainName为配置的url路径
        // 这里会以用户配置的url路径来创建一个SimpleNamedFilterList示例;  并添加到DefaultFilterChainManager内部的Map<String, NamedFilterList>类型的类级字段filterChains中(以用户配置的url路径为key——即filterChainDefinitions参数里每一行等号左边的部分)
        NamedFilterList chain = ensureChain(chainName);
        chain.add(filter);
    }

说明

前面八小节主要分析了shiroFilterFactoryBean创建一个实例的流程，主要包含创建FilterChainManager，filter的

装载到链的过程，后面部分主要是讲filter生效的过程源码。

至此，FilterChainManager就创建完了，它无非就是缓存了两张map，没有什么逻辑上的操作。下面将FilterChainManager设置到PathMatchingFilterChainResolver中。PathMatchingFilterChainResolver实现了FilterChainResolver接口，该接口中只定义了一个方法：

FilterChain getChain(ServletRequest request, ServletResponse response, FilterChain originalChain);

通过解析请求来得到一个新的FilterChain。而PathMatchingFilterChainResolver实现了该接口，依靠了FilterChainManager中保存的chainFilters和filters这两张map来根据请求路径解析出相应的filterChain，并且和originalChain组合起来使用。下面具体看看PathMatchingFilterChainResolver中的实现：

public FilterChain getChain(ServletRequest request, ServletResponse response, FilterChain originalChain) {
        // 得到 FilterChainManager 
        FilterChainManager filterChainManager = getFilterChainManager();
        if (!filterChainManager.hasChains()) {
            return null;
        }
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        String requestURI = getPathWithinApplication(request);
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        // chainNames就是刚定义的filterChains的keySet，也就是所有的路径集合(比如：["/resources/**","/login"])
        for (String pathPattern : filterChainManager.getChainNames()) {
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            // 请求路径是否匹配某个 定义好的路径:
            if (pathMatches(pathPattern, requestURI)) {
                if (log.isTraceEnabled()) {
                    log.trace("Matched path pattern [" + pathPattern + "] for requestURI [" + requestURI + "].  " + "Utilizing corresponding filter chain...");
                }
                // 找到第一个匹配的Filter链，那么就返回一个ProxiedFilterChain
                return filterChainManager.proxy(originalChain, pathPattern);
            }
        }
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        return null;
    }

这里返回只有两种情况，要么是null，要么就是一个ProxiedFilterChain。返回null并不表示中断FilterChain，而是只用originChain。而关于ProxiedFilterChain，它实现了FilterChain，内部维护了两份FilterChain（其实一个是FilterChain，另一个是List<Filter>） FilterChain也就是web.xml中注册的Filter形成的FilterChain，我们称之为originChain。而另一个List<Filter>则是我们在Shiro中注册的Filter链了，下面看看ProxiedFilterChain中关于doFilter(...)的实现：

public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
        if (this.filters == null || this.filters.size() == this.index) {
            //we‘ve reached the end of the wrapped chain, so invoke the original one:
            if (log.isTraceEnabled()) {
                log.trace("Invoking original filter chain.");
            }
            this.orig.doFilter(request, response);
        } else {
            if (log.isTraceEnabled()) {
                log.trace("Invoking wrapped filter at index [" + this.index + "]");
            }
            this.filters.get(this.index++).doFilter(request, response, this);
        }
    }

可以看到，它会先执行Shiro中执行的filter，然后再执行web.xml中的Filter。不过要注意的是，需要等到originChain执行到ShiroFilter之后才会执行Shiro中的Filter链。至此，两个组件的创建过程差不多都介绍完了，那么当这两个组件创建完毕后，是如何工作的呢？先从ShiroFilter入手，因为它是总的拦截器，看看其中的doFilterInternal(...)方法：

protected void doFilterInternal(ServletRequest servletRequest, ServletResponse servletResponse, final FilterChain chain)
            throws ServletException, IOException {
?
        Throwable t = null;
?
        try {
            final ServletRequest request = prepareServletRequest(servletRequest, servletResponse, chain);
            final ServletResponse response = prepareServletResponse(request, servletResponse, chain);
?
            final Subject subject = createSubject(request, response);
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            //noinspection unchecked
            subject.execute(new Callable() {
                public Object call() throws Exception {
                    // 其实需要关心的就在这里
                    // touch一下session
                    updateSessionLastAccessTime(request, response);
                    // 执行Filter链
                    executeChain(request, response, chain);
                    return null;
                }
            });
        } catch (ExecutionException ex) {
            t = ex.getCause();
        } catch (Throwable throwable) {
            t = throwable;
        }
?
        if (t != null) {
            if (t instanceof ServletException) {
                throw (ServletException) t;
            }
            if (t instanceof IOException) {
                throw (IOException) t;
            }
            //otherwise it‘s not one of the two exceptions expected by the filter method signature - wrap it in one:
            String msg = "Filtered request failed.";
            throw new ServletException(msg, t);
        }
    }
跟进executeChain(...)方法：

    protected void executeChain(ServletRequest request, ServletResponse response, FilterChain origChain)
            throws IOException, ServletException {
        FilterChain chain = getExecutionChain(request, response, origChain);
        chain.doFilter(request, response);
    }

如何得到FilterChain的呢？如果你认真的看到这里，那么你应该不难想到其中肯定利用了刚才注册的ChainResolver:

protected FilterChain getExecutionChain(ServletRequest request, ServletResponse response, FilterChain origChain) {
        FilterChain chain = origChain;
?
        FilterChainResolver resolver = getFilterChainResolver();
        if (resolver == null) {
            log.debug("No FilterChainResolver configured.  Returning original FilterChain.");
            return origChain;
        }
?
        FilterChain resolved = resolver.getChain(request, response, origChain);
        if (resolved != null) {
            log.trace("Resolved a configured FilterChain for the current request.");
            chain = resolved;
        } else {
            log.trace("No FilterChain configured for the current request.  Using the default.");
        }
?
        return chain;
    }

猜对了~并且也验证了当resolver.getChain(...)返回null时，直接使用originChain了。然后执行返回的FilterChain的doFilter(...)方法。这个过程我们再脱离代码来分析一下：当我们从浏览器发出一个请求，究竟发生了什么？这里只站在Filter的层面来分析。服务器启动后，读取web.xml中的filter、filter-mapping节点后组成FilterChain，对请求进行拦截。拦截的顺序按照filter节点的定义顺序，Shiro利用ShiroFilter来充当一个总的拦截器来分发所有需要被Shiro拦截的请求，所以我们看到在Shiro中我们还可以自定义拦截器。ShiroFilter根据它在拦截器中的位置，只要执行到了那么就会暂时中断原FilterChain的执行，先执行Shiro中定义的Filter，最后再执行原FilterChian。可以打个比方，比如说本来有一条铁链，一直蚂蚁从铁链的开端往末端爬，其中某一环叫ShiroFilter，那么当蚂蚁爬到ShiroFilter这一环时，将铁链打断，并且接上另一端铁链（Shiro中自定义的Filter），这样就构成了一条新的铁链。然后蚂蚁继续爬行（后续的执行过程）。

到这里，我们已经根据请求路径找到了一条Filter链（originChain + shiroChain），之后就是对链上的Filter做doFilter，其中关于如何就是filter后配置的[]部分是如何生效的，我们可以看PathMatchingFilter中的Prehandle(...)方法：

protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
?
        if (this.appliedPaths == null || this.appliedPaths.isEmpty()) {
            if (log.isTraceEnabled()) {
                log.trace("appliedPaths property is null or empty.  This Filter will passthrough immediately.");
            }
            return true;
        }
?
        // appliedPaths中保存了该filter中能拦截的路径和该路径配置的key-value对，比如{key="/admin/**", value="[admin]"}
        for (String path : this.appliedPaths.keySet()) {
            // 首先是匹配路径
            if (pathsMatch(path, request)) {
                log.trace("Current requestURI matches pattern ‘{}‘.  Determining filter chain execution...", path);
                // 然后开始验证“[]”中的字符串
                Object config = this.appliedPaths.get(path);
                return isFilterChainContinued(request, response, path, config);
            }
        }
?
        //no path matched, allow the request to go through:
        return true;
    }

下面跟踪isFilterChainContinued(...)：

private boolean isFilterChainContinued(ServletRequest request, ServletResponse response,
                                           String path, Object pathConfig) throws Exception {
?
        if (isEnabled(request, response, path, pathConfig)) { //isEnabled check added in 1.2
            if (log.isTraceEnabled()) {
                 // log
            }
            return onPreHandle(request, response, pathConfig);
        }
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        if (log.isTraceEnabled()) {
            // log
        }
        return true;
    }

基本也就是交给onPreHandle(...)来处理，所以一般需要验证”[]“中字符串的filter都会扩展这个方法，比如AccessControlFilter：

public boolean onPreHandle(ServletRequest request, ServletResponse response, Object mappedValue) throws Exception {
        return isAccessAllowed(request, response, mappedValue) || onAccessDenied(request, response, mappedValue);
    }
 // 而RolesAuthorizationFilter中：

 public boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws IOException {
?
        Subject subject = getSubject(request, response);
        String[] rolesArray = (String[]) mappedValue;
?
        if (rolesArray == null || rolesArray.length == 0) {
            //no roles specified, so nothing to check - allow access.
            return true;
        }
?
        Set<String> roles = CollectionUtils.asSet(rolesArray);
        return subject.hasAllRoles(roles);
    }

细节

这里面就牵扯出一个有趣的问题 : FactoryBean<T>接口的getObject方法和 BeanPostProcessor接口的postProcessBeforeInitialization的执行先后顺序？

为了保证不遗漏Filter，我们可以猜测后者必须优先于前者。因为创建实例要读取初始化的默认filter

上面这个说法参考下面第一个博客的说法有一点要注意的是，打断点调试确实是postProcessBeforeInitialization先进去的但是并没有进去找到任何的filter，因为我是注解提供的filterMap，所以是在执行createFilterChainManager的时候先查找default的filter再添加我们在config类中传进去的flterMap解析filter到filterChainManager中。我猜测如果是有xml配置的话，应该是postProcessBeforeInitialization最先读取xml配置中的filter的，但是如果是xml配置应该是一开始在postProcessBeforeInitialization中是找不到的

总结

在两位大佬的基础上进行了理解，代码的一步步跟踪，分析源代码的时候结合ide的debug功能打断点一行行的跳转，加深理解，再加上自己的注释，后面那位花了两天时间走完了，我也差不多，哈哈哈哈哈。。做个笔记，防止忘记。

参考

参考文章:https://blog.csdn.net/lqzkcx3/article/details/78776555

https://blog.csdn.net/u012345283/article/details/44199791

![1588042373222](C:\Users\Henry Hu.DESKTOP-C8EDL2H\AppData\Roaming\Typora\typora-user-images\1588042373222.png)

Shiro源码分析-ShiroFilterFactoryBean

Shiro源码分析-ShiroFilterFactoryBean 2020-04-29

说明

细节

总结

参考

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