SpringMVC之HandlerMapping源码分析

01.doDispatch方法中代码如下：
HandlerExecutionChain  mappedHandler=this.getHandler(processedRequest)

 02.DispatcherServlet类中   找到getHandler()
 protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
 Iterator var2 = this.handlerMappings.iterator();
 HandlerMapping hm = (HandlerMapping)var2.next();
 handler = hm.getHandler(request);
 }

 03.我们转而去找HandlerMapping的getHandler()
 却发现HandlerMapping是一个接口，所以我们就去找它的实现类AbstractHandlerMapping
 -的getHandler() 如下：
  public final HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception{
    //将request转换成一个Handler
     Object handler = this.getHandlerInternal(request);
     return this.getHandlerExecutionChain(handler, request);
  }

  04. protected HandlerExecutionChain getHandlerExecutionChain(Object handler, HttpServletRequest request) {
      HandlerExecutionChain chain = handler instanceof HandlerExecutionChain ? (HandlerExecutionChain)handler : new HandlerExecutionChain(handler);
       String lookupPath = this.urlPathHelper.getLookupPathForRequest(request);
              Iterator var5 = this.adaptedInterceptors.iterator();

              while(var5.hasNext()) {
                  HandlerInterceptor interceptor = (HandlerInterceptor)var5.next();
                  if (interceptor instanceof MappedInterceptor) {
                      MappedInterceptor mappedInterceptor = (MappedInterceptor)interceptor;
                      if (mappedInterceptor.matches(lookupPath, this.pathMatcher)) {
                          chain.addInterceptor(mappedInterceptor.getInterceptor());
                      }
                  } else {
                      chain.addInterceptor(interceptor);
                  }
              }

              return chain;
    }

     结论：处理器执行链=1个Handler+N个Interceptor