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前面一篇博客介绍了HandlerMapping这个组件，它负责的是定位请求处理器Handler。这是SpringMvc处理流程的第二步。那么，当定位到Handler之后，DispatcherServlet会将得到的Handler告知HandlerAdapter，HandlerAdapter再根据请求去定位请求的具体处理方法是哪一个。public abstract interface HandlerAdapter
{
public abstract boolean supports(Object paramObject);
public abstract ModelAndView handle(HttpServletRequest paramHttpServletRequest, HttpServletResponse paramHttpServletResponse, Object paramObject)
throws Exception;
public abstract long getLastModified(HttpServletRequest paramHttpServletRequest, Object paramObject);
}public boolean supports(Object handler) {
return getMethodResolver(handler).hasHandlerMethods();
}
private ServletHandlerMethodResolver getMethodResolver(Object handler) {
Class handlerClass = ClassUtils.getUserClass(handler);
ServletHandlerMethodResolver resolver = this.methodResolverCache.get(handlerClass);
if (resolver == null) {
resolver = new ServletHandlerMethodResolver(handlerClass);
this.methodResolverCache.put(handlerClass, resolver);
}
return resolver;
} public ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
if (AnnotationUtils.findAnnotation(handler.getClass(), SessionAttributes.class) != null) {
// Always prevent caching in case of session attribute management.
checkAndPrepare(request, response, this.cacheSecondsForSessionAttributeHandlers, true);
// Prepare cached set of session attributes names.
}
else {
// Uses configured default cacheSeconds setting.
checkAndPrepare(request, response, true);
}
// Execute invokeHandlerMethod in synchronized block if required.
if (this.synchronizeOnSession) {
HttpSession session = request.getSession(false);
if (session != null) {
Object mutex = WebUtils.getSessionMutex(session);
synchronized (mutex) {
return invokeHandlerMethod(request, response, handler);
}
}
}
return invokeHandlerMethod(request, response, handler);
} protected ModelAndView invokeHandlerMethod(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
ServletHandlerMethodResolver methodResolver = getMethodResolver(handler);
Method handlerMethod = methodResolver.resolveHandlerMethod(request);
ServletHandlerMethodInvoker methodInvoker = new ServletHandlerMethodInvoker(methodResolver);
ServletWebRequest webRequest = new ServletWebRequest(request, response);
ExtendedModelMap implicitModel = new BindingAwareModelMap();
Object result = methodInvoker.invokeHandlerMethod(handlerMethod, handler, webRequest, implicitModel);
ModelAndView mav =
methodInvoker.getModelAndView(handlerMethod, handler.getClass(), result, implicitModel, webRequest);
methodInvoker.updateModelAttributes(handler, (mav != null ? mav.getModel() : null), implicitModel, webRequest);
return mav;
} Spring学习总结(2.3)-Spring MVC:handlerAdapter
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原文地址：http://blog.csdn.net/zhuojiajin/article/details/46597687
