Tomcat8.x web.xml过滤器的配置的解析->过滤器的实例化->过滤器的调用

Tomcat8.x web.xml过滤器的配置的解析->过滤器的实例化->过滤器的调用

// web.xml过滤器的配置的解析、过滤器的实例化、过滤器的调用
		 // web.xml过滤器的配置的解析、过滤器的实例化-------------1
		 class org.apache.catalina.core.StandardContext{
			 protected synchronized void startInternal() throws LifecycleException {
				 	// 解析上下文的web.xml文件
				 	fireLifecycleEvent(Lifecycle.CONFIGURE_START_EVENT, null); // 触发事件 "configure_start"-------
				 	
				 	if (ok) {
		            	 // 启动过滤器，会把org.apache.tomcat.util.descriptor.web.FilterDef 转成对象 org.apache.catalina.core.ApplicationFilterConfig
		                if (!filterStart()) {
		                    log.error(sm.getString("standardContext.filterFail"));
		                    ok = false;
		                }
		            }
			 }
			 
			 // 把org.apache.tomcat.util.descriptor.web.FilterDef 转成对象 org.apache.catalina.core.ApplicationFilterConfig
			 public boolean filterStart() {
			        // Instantiate and record a FilterConfig for each defined filter
			        boolean ok = true;
			        synchronized (filterConfigs) {
			            filterConfigs.clear();
			            for (Entry<String,FilterDef> entry : filterDefs.entrySet()) {
			                String name = entry.getKey();
			                    ApplicationFilterConfig filterConfig =
			                            new ApplicationFilterConfig(this, entry.getValue());
			                    filterConfigs.put(name, filterConfig);
			            }
			        }
			        return ok;
		    }
		 }
		 
		 // 解析上下文的web.xml文件
		 class org.apache.catalina.startup.ContextConfig{
			 public void lifecycleEvent(LifecycleEvent event) {
				 context = (Context) event.getLifecycle(); // 取得触发者 org.apache.catalina.core.StandardContext
				 if (event.getType().equals(Lifecycle.CONFIGURE_START_EVENT)) { // "configure_start"
			            configureStart();
			     }
			 }
			 
			 // 配置启动事件 "configure_start"-------
			 protected synchronized void configureStart() {
				 	// 读取并解析“d:/a/c/d/tomcat/conf/web.xml”，读取并解析"d:/a/b/tomcat/conf/Catalina/localhost/web.xml.default"
			        // 取得输入流 "d:/a/b/c/tomcat/webapps/dir1/WEB-INF/web.xml"
			        // 合并配置文件内容
			        // 合并全局配置
			        // 使用 org.apache.jasper.servlet.JspServlet 包装  <jsp-file>/a/b/c/file.jsp</jsp-file>的文件
			        // 把解析处理的内容设置到 context 中 ，如：context.addFilterMap(filterMap);
			        webConfig();//!!!!  核心
			 }
			 
			 protected void webConfig() {
				 WebXml webXml = createWebXml();

		         // Parse context level web.xml
		         // 取得输入流 "d:/a/b/c/tomcat/webapps/dir1/WEB-INF/web.xml"
		         InputSource contextWebXml = getContextWebXmlSource();
		         if (!webXmlParser.parseWebXml(contextWebXml, webXml, false)) { // 解析文件 ，数据存入webXml
		            ok = false;
		         }
				 // context === org.apache.catalina.core.StandardContext
				 configureContext(webXml); // 把解析处理的内容设置到 context 中 ，如：context.addFilterMap(filterMap);
			 }
			 
			 //过滤器的配置信息
			 private void configureContext(WebXml webxml) {
				 	// context === org.apache.catalina.core.StandardContext
			        for (FilterDef filter : webxml.getFilters().values()) { // 过滤器
			            if (filter.getAsyncSupported() == null) {
			                filter.setAsyncSupported("false");
			            }
			            context.addFilterDef(filter);
			        }
			        for (FilterMap filterMap : webxml.getFilterMappings()) { // 过滤器映射
			            context.addFilterMap(filterMap);
			        }
			 }
		 }
		 
		 // 过滤器的调用-------------------2
		 class org.apache.catalina.core.StandardWrapperValve{
			 public final void invoke(Request request, Response response)
				        throws IOException, ServletException {
				 	// ....
				 	// !!! 创建过滤器链条
			        ApplicationFilterChain filterChain =
			                ApplicationFilterFactory.createFilterChain(request, wrapper, servlet);
			        // ....
			        // 执行过滤器链!!!!
                    filterChain.doFilter(request.getRequest(), response.getResponse());
			 }
		 }
		 
		 // 过滤器链条
		 class org.apache.catalina.core.ApplicationFilterChain{
			 public static ApplicationFilterChain createFilterChain(ServletRequest request,
			            Wrapper wrapper, Servlet servlet) {
				 	ApplicationFilterChain filterChain = null;
				 	filterChain = (ApplicationFilterChain) req.getFilterChain();
	                if (filterChain == null) {
	                    filterChain = new ApplicationFilterChain(); // 创建过滤器链
	                    req.setFilterChain(filterChain);
	                }
	                filterChain.setServlet(servlet);
	                filterChain.setServletSupportsAsync(wrapper.isAsyncSupported());

	                // Acquire the filter mappings for this Context
	                StandardContext context = (StandardContext) wrapper.getParent();
	                FilterMap filterMaps[] = context.findFilterMaps(); //上下文的过滤器列表
	                for (int i = 0; i < filterMaps.length; i++) { // 添加过滤器，根据路径映射
	                    if (!matchDispatcher(filterMaps[i] ,dispatcher)) {
	                        continue;
	                    }
	                    if (!matchFiltersURL(filterMaps[i], requestPath))
	                        continue;
	                    // 在org.apache.catalina.core.StandardContext.filterStart() 已经把
	                    // context === org.apache.catalina.core.StandardContext
	                    // filterConfig === org.apache.catalina.core.ApplicationFilterConfig
	                    ApplicationFilterConfig filterConfig = (ApplicationFilterConfig)
	                        context.findFilterConfig(filterMaps[i].getFilterName());
	                    if (filterConfig == null) {
	                        // FIXME - log configuration problem
	                        continue;
	                    }
	                    filterChain.addFilter(filterConfig);
	                }

	                // Add filters that match on servlet name second
	                for (int i = 0; i < filterMaps.length; i++) { // 添加过滤器，根据Servlet名称
	                    if (!matchDispatcher(filterMaps[i] ,dispatcher)) {
	                        continue;
	                    }
	                    if (!matchFiltersServlet(filterMaps[i], servletName))
	                        continue;
	                    ApplicationFilterConfig filterConfig = (ApplicationFilterConfig)
	                        context.findFilterConfig(filterMaps[i].getFilterName());
	                    if (filterConfig == null) {
	                        // FIXME - log configuration problem
	                        continue;
	                    }
	                    filterChain.addFilter(filterConfig);
	                }

	                // Return the completed filter chain
	                return filterChain;
			 }
			 
			 // 执行过滤器链条
			 public void doFilter(ServletRequest request, ServletResponse response)
				        throws IOException, ServletException {
				 internalDoFilter(request,response);//!!!!
			 }
			 
			 // 执行过滤器链条
			 private void internalDoFilter(ServletRequest request,
                     ServletResponse response)
                    		 	throws IOException, ServletException {
				 if (pos < n) {
					 	// org.apache.catalina.core.StandardContext.filterStart() 创建的ApplicationFilterConfig
			            ApplicationFilterConfig filterConfig = filters[pos++];
		                Filter filter = filterConfig.getFilter();	 
		                filter.doFilter(request, response, this);//!!!!执行过滤器
				 }
				 servlet.service(request, response); // 执行Servlet
			 }
		 }