【转载】SpringMVC学习笔记

转载于：SpringMVC笔记

SpringMVC

1.SpringMVC概述

MVC：

• Model（模型）： 数据模型，提供要展示的数据，：Value Object（数据Dao） 和 服务层（行为Service），提供数据和业务。

• View（视图）： 负责进行模型的展示，即用户界面

• Controller（控制器）： 调度员，接收用户请求，委托给模型进行处理（状态改变），处理完毕后把返回的模型数据返回给视图，由视图负责展示。

SpringMVC的特点：

• Spring为展现层提供的基于MVC设计理念的Web框架

• SpirngMVC通过一套MVC注解，让POJO成为处理请求的控制器，而无须实现任何接口

• 支持REST风格的URL请求

• 采用了松散耦合可拔插组件结构，扩展性和灵活性

2. HelloWorld

1. 导入依赖

spring-webmvc的maven依赖

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>4.0.0.RELEASE</version>
    </dependency>
    
	<!--        核心包-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.0.0.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>4.0.0.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>4.0.0.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-expression</artifactId>
        <version>4.0.0.RELEASE</version>
    </dependency>

   <!--       日志包-->
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.3</version>
    </dependency>
    
	<!--        注解支持包-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>4.0.0.RELEASE</version>
    </dependency>
&lt;/dependencies&gt;</pre> 
DispatcherServlet
&lt;!--注册DispatcherServlet,请求分发器（前端控制器）--&gt;
&lt;servlet&gt;
    &lt;servlet-name&gt;springDispatcherServlet&lt;/servlet-name&gt;
    &lt;servlet-class&gt;org.springframework.web.servlet.DispatcherServlet&lt;/servlet-class&gt;
    &lt;!--绑定Spring配置文件--&gt;
    &lt;init-param&gt;
        &lt;param-name&gt;contextConfigLocation&lt;/param-name&gt;
        &lt;param-value&gt;classpath:springmvc-config.xml&lt;/param-value&gt;
    &lt;/init-param&gt;
    &lt;!--启动级别为1，即服务器启动后就启动--&gt;
    &lt;!--值越小优先级越高，越先创建对象--&gt;
    &lt;load-on-startup&gt;1&lt;/load-on-startup&gt;
&lt;/servlet&gt;

&lt;!-- /  拦截所有的请求；（不包括.jsp，jsp由Tomcat来处理），
	覆盖了父类的DispatcherServlet的pattern，静态资源被拦截。--&gt;
&lt;!-- *.jsp 拦截jsp请求，覆盖了父类的JspServlet--&gt;
&lt;!-- /* 拦截所有的请求；（包括.jsp，一旦拦截jsp页面就不能显示了）--&gt;
&lt;servlet-mapping&gt;
    &lt;servlet-name&gt;springDispatcherServlet&lt;/servlet-name&gt;
    &lt;url-pattern&gt;/&lt;/url-pattern&gt;
&lt;/servlet-mapping&gt;
InternalResourceViewResolver
&lt;!--开启包扫描,让指定包下的注解生效,由IOC容器统一管理--&gt;
&lt;context:component-scan base-package="com.xiao.controller"/&gt;

&lt;!--配置视图解析器，拼接视图名字，找到对应的视图--&gt;
&lt;bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"&gt;
    &lt;!--前缀--&gt;
    &lt;property name="prefix" value="/WEB-INF/page/"/&gt;
    &lt;!--后缀--&gt;
    &lt;property name="suffix" value=".jsp"/&gt;
&lt;/bean&gt;
@RequestMapping("/hello01")
public String toSuccess(){
    System.out.println("请求成功页面");
    return "success";
}
@RequestMapping("/hello02")
public String toError() {
    System.out.println("请求错误页面");
    return "error";
}
@RequestMapping("/hello01")
/
/haha/hello01
dispatcherServlet-servlet.xml
url-pattern=/
@RequestParam
required=false
defaultValue
@RequestHeader
@CookieValue
${requestScope.reqParam}
@SessionAttributes
@SessionAttributes(value = "msg")
@SessionAttributes(types = {String.class})
@ModelAttribute
    if (this.detectAllHandlerMappings) {
        // Find all HandlerMappings in the ApplicationContext, including ancestor contexts.
        Map&lt;String, HandlerMapping&gt; matchingBeans =
                BeanFactoryUtils.beansOfTypeIncludingAncestors(context, HandlerMapping.class, true, false);
        if (!matchingBeans.isEmpty()) {
            this.handlerMappings = new ArrayList&lt;HandlerMapping&gt;(matchingBeans.values());
            // We keep HandlerMappings in sorted order.
            OrderComparator.sort(this.handlerMappings);
        }
    }
    else {
        try {
            HandlerMapping hm = context.getBean(HANDLER_MAPPING_BEAN_NAME, HandlerMapping.class);
            this.handlerMappings = Collections.singletonList(hm);
        }
        catch (NoSuchBeanDefinitionException ex) {
            // Ignore, we'll add a default HandlerMapping later.
        }
    }

    // Ensure we have at least one HandlerMapping, by registering
    // a default HandlerMapping if no other mappings are found.
    if (this.handlerMappings == null) {
        this.handlerMappings = getDefaultStrategies(context, HandlerMapping.class);
        if (logger.isDebugEnabled()) {
            logger.debug("No HandlerMappings found in servlet '" + getServletName() + "': using default");
        }
    }
}</pre> 
            //1、检查是否文件上传请求
            
            processedRequest = checkMultipart(request);
            multipartRequestParsed = processedRequest != request;
            
            // Determine handler for the current request.
            //2、根据当前的请求地址找到那个类能来处理；
            
            mappedHandler = getHandler(processedRequest);

            //3、如果没有找到哪个处理器（控制器）能处理这个请求就404，或者抛异常
            
            if (mappedHandler == null || mappedHandler.getHandler() == null) {
                noHandlerFound(processedRequest, response);
                return;
            }

            // Determine handler adapter for the current request.
            //4、拿到能执行这个类的所有方法的适配器；（反射工AnnotationMethodHandlerAdapter）
            
            HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());
            
            // Process last-modified header, if supported by the handler.
            
            String method = request.getMethod();
            boolean isGet = "GET".equals(method);
            if (isGet || "HEAD".equals(method)) {
                long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
                if (logger.isDebugEnabled()) {
                    String requestUri = urlPathHelper.getRequestUri(request);
                    logger.debug("Last-Modified value for [" + requestUri + "] is: " + lastModified);
                }
                if (new ServletWebRequest(request, response).checkNotModified(lastModified) &amp;&amp; isGet) {
                    return;
                }
            }
            if (!mappedHandler.applyPreHandle(processedRequest, response)) {
                return;
            }
            try {
                
                // Actually invoke the handler.处理（控制）器的方法被调用
                //控制器（Controller），处理器（Handler）
                //5、适配器来执行目标方法；
                //将目标方法执行完成后的返回值作为视图名，设置保存到ModelAndView中
                //目标方法无论怎么写，最终适配器执行完成以后都会将执行后的信息封装成ModelAndView
                
                mv = ha.handle(processedRequest,response,mappedHandler.getHandler());
            } finally {
                if (asyncManager.isConcurrentHandlingStarted()) {
                    return;
                }
            }
            applyDefaultViewName(request, mv);//如果没有视图名设置一个默认的视图名；
            mappedHandler.applyPostHandle(processedRequest, response, mv);
        } catch (Exception ex) {
            dispatchException = ex;
        }
        
        //转发到目标页面；
        //6、根据方法最终执行完成后封装的ModelAndView；
        //转发到对应页面，而且ModelAndView中的数据可以从请求域中获取
        processDispatchResult(processedRequest, response, mappedHandler, 
                              mv, dispatchException);
    } catch (Exception ex) {
        triggerAfterCompletion(processedRequest, response, mappedHandler, ex);
    } catch (Error err) {
        triggerAfterCompletionWithError(processedRequest, response, mappedHandler, err);
    } finally {
        if (asyncManager.isConcurrentHandlingStarted()) {
            
            // Instead of postHandle and afterCompletion
            mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response);
            return;
        }
        // Clean up any resources used by a multipart request.
        if (multipartRequestParsed) {
            cleanupMultipart(processedRequest);
        }
    }
}</pre> 
    ExtendedModelMap implicitModel = new BindingAwareModelMap();//**重点

     //真正执行目标方法；目标方法利用反射执行期间确定参数值，提前执行modelattribute等所有的操作都在这个方法中；
    Object result = methodInvoker.invokeHandlerMethod(handlerMethod, handler, webRequest, implicitModel);
	//=======================看后边补充的代码块===========================
    ModelAndView mav =
            methodInvoker.getModelAndView(handlerMethod, handler.getClass(), result, implicitModel, webRequest);

    methodInvoker.updateModelAttributes(handler, (mav != null ? mav.getModel() : null), implicitModel, webRequest);

    return mav;
}</pre> 
      //找到所有@ModelAttribute注解标注的方法；
        for (Method attributeMethod : this.methodResolver.getModelAttributeMethods()) {
            Method attributeMethodToInvoke = BridgeMethodResolver.findBridgedMethod(attributeMethod);
            //先确定modelattribute方法执行时要使用的每一个参数的值；
           Object[] args = resolveHandlerArguments(attributeMethodToInvoke, handler, webRequest, implicitModel);
   //==========================看后边补充的代码块=====================================
            if (debug) {
                logger.debug("Invoking model attribute method: " + attributeMethodToInvoke);
            }
            String attrName = AnnotationUtils.findAnnotation(attributeMethod, ModelAttribute.class).value();
            
            if (!"".equals(attrName) &amp;&amp; implicitModel.containsAttribute(attrName)) {
                continue;
            }
            
            ReflectionUtils.makeAccessible(attributeMethodToInvoke);
           
           //提前运行ModelAttribute，
            Object attrValue = attributeMethodToInvoke.invoke(handler, args);
            if ("".equals(attrName)) {
                Class&lt;?&gt; resolvedType = GenericTypeResolver.resolveReturnType(attributeMethodToInvoke, handler.getClass());
                attrName = Conventions.getVariableNameForReturnType(attributeMethodToInvoke, resolvedType, attrValue);
            }
            
            /*
            
            方法上标注的ModelAttribute注解如果有value值   
			@ModelAttribute("abc")
			hahaMyModelAttribute()
			
            标了:	attrName="abc"
            没标:	attrName="";attrName就会变为返回值类型首字母小写，
                 比如void ,或者book;
                 
                 【  
                    @ModelAttribute标在方法上的另外一个作用；
                    可以把方法运行后的返回值按照方法上@ModelAttribute("abc")
                    指定的key放到隐含模型中；
                    如果没有指定这个key；就用返回值类型的首字母小写
                  】
                    
                    {
                        haha=Book [id=100, bookName=西游记, author=吴承恩, stock=98, 									sales=10, price=98.98], 
                        void=null
                  	}
            */
            //把提前运行的ModelAttribute方法的返回值也放在隐含模型中
            if (!implicitModel.containsAttribute(attrName)) {
                implicitModel.addAttribute(attrName, attrValue);
            }
        }

           //再次解析目标方法参数是哪些值
        Object[] args = resolveHandlerArguments(handlerMethodToInvoke, handler, webRequest, implicitModel);
        if (debug) {
            logger.debug("Invoking request handler method: " + handlerMethodToInvoke);
        }
        ReflectionUtils.makeAccessible(handlerMethodToInvoke);

        
        //执行目标方法
        return handlerMethodToInvoke.invoke(handler, args);
    }
    catch (IllegalStateException ex) {
        // Internal assertion failed (e.g. invalid signature):
        // throw exception with full handler method context...
        throw new HandlerMethodInvocationException(handlerMethodToInvoke, ex);
    }
    catch (InvocationTargetException ex) {
        // User-defined @ModelAttribute/@InitBinder/@RequestMapping method threw an exception...
        ReflectionUtils.rethrowException(ex.getTargetException());
        return null;
    }
}</pre> 
    for (int i = 0; i &lt; args.length; i++) {
        MethodParameter methodParam = new MethodParameter(handlerMethod, i);
        methodParam.initParameterNameDiscovery(this.parameterNameDiscoverer);
        GenericTypeResolver.resolveParameterType(methodParam, handler.getClass());
        String paramName = null;
        String headerName = null;
        boolean requestBodyFound = false;
        String cookieName = null;
        String pathVarName = null;
        String attrName = null;
        boolean required = false;
        String defaultValue = null;
        boolean validate = false;
        Object[] validationHints = null;
        int annotationsFound = 0;
        Annotation[] paramAnns = methodParam.getParameterAnnotations();
        
        //找到目标方法这个参数的所有注解，如果有注解就解析并保存注解的信息；
        for (Annotation paramAnn : paramAnns) {
            if (RequestParam.class.isInstance(paramAnn)) {
                RequestParam requestParam = (RequestParam) paramAnn;
                paramName = requestParam.value();
                required = requestParam.required();
                defaultValue = parseDefaultValueAttribute(requestParam.defaultValue());
                annotationsFound++;
            }
            else if (RequestHeader.class.isInstance(paramAnn)) {
                RequestHeader requestHeader = (RequestHeader) paramAnn;
                headerName = requestHeader.value();
                required = requestHeader.required();
                defaultValue = parseDefaultValueAttribute(requestHeader.defaultValue());
                annotationsFound++;
            }
            else if (RequestBody.class.isInstance(paramAnn)) {
                requestBodyFound = true;
                annotationsFound++;
            }
            else if (CookieValue.class.isInstance(paramAnn)) {
                CookieValue cookieValue = (CookieValue) paramAnn;
                cookieName = cookieValue.value();
                required = cookieValue.required();
                defaultValue = parseDefaultValueAttribute(cookieValue.defaultValue());
                annotationsFound++;
            }
            else if (PathVariable.class.isInstance(paramAnn)) {
                PathVariable pathVar = (PathVariable) paramAnn;
                pathVarName = pathVar.value();
                annotationsFound++;
            }
            else if (ModelAttribute.class.isInstance(paramAnn)) {
                ModelAttribute attr = (ModelAttribute) paramAnn;
                attrName = attr.value();
                annotationsFound++;
            }
            else if (Value.class.isInstance(paramAnn)) {
                defaultValue = ((Value) paramAnn).value();
            }
            else if (paramAnn.annotationType().getSimpleName().startsWith("Valid")) {
                validate = true;
                Object value = AnnotationUtils.getValue(paramAnn);
                validationHints = (value instanceof Object[] ? (Object[]) value : new Object[] {value});
            }
        }
        if (annotationsFound &gt; 1) {
            throw new IllegalStateException("Handler parameter annotations are exclusive choices - " +
                    "do not specify more than one such annotation on the same parameter: " + handlerMethod);
        }

         //没有找到注解的情况；
        if (annotationsFound == 0) {
            
            //解析普通参数
            Object argValue = resolveCommonArgument(methodParam, webRequest);
            //=====================看后边补充的代码块=========================
             //会进入resolveStandardArgument（解析标准参数）
            
            
            if (argValue != WebArgumentResolver.UNRESOLVED) {
                args[i] = argValue;
            }
            else if (defaultValue != null) {
                args[i] = resolveDefaultValue(defaultValue);
            }
            else {
                
           //判断是否是Model或者是Map旗下的，如果是将之前创建的隐含模型直接赋值给这个参数
                Class&lt;?&gt; paramType = methodParam.getParameterType();
                if (Model.class.isAssignableFrom(paramType) || Map.class.isAssignableFrom(paramType)) {
                    if (!paramType.isAssignableFrom(implicitModel.getClass())) {
                        throw new IllegalStateException("Argument [" + paramType.getSimpleName() + "] is of type " +
                                "Model or Map but is not assignable from the actual model. You may need to switch " +
                                "newer MVC infrastructure classes to use this argument.");
                    }
                    args[i] = implicitModel;
                }
                else if (SessionStatus.class.isAssignableFrom(paramType)) {
                    args[i] = this.sessionStatus;
                }
                else if (HttpEntity.class.isAssignableFrom(paramType)) {
                    args[i] = resolveHttpEntityRequest(methodParam, webRequest);
                }
                else if (Errors.class.isAssignableFrom(paramType)) {
                    throw new IllegalStateException("Errors/BindingResult argument declared " +
                            "without preceding model attribute. Check your handler method signature!");
                }
                else if (BeanUtils.isSimpleProperty(paramType)) {
                    paramName = "";
                }
                else {
                    attrName = "";
                }
            }
        }


           //确定值的环节
        if (paramName != null) {
            args[i] = resolveRequestParam(paramName, required, defaultValue, methodParam, webRequest, handler);
        }
        else if (headerName != null) {
            args[i] = resolveRequestHeader(headerName, required, defaultValue, methodParam, webRequest, handler);
        }
        else if (requestBodyFound) {
            args[i] = resolveRequestBody(methodParam, webRequest, handler);
        }
        else if (cookieName != null) {
            args[i] = resolveCookieValue(cookieName, required, defaultValue, methodParam, webRequest, handler);
        }
        else if (pathVarName != null) {
            args[i] = resolvePathVariable(pathVarName, methodParam, webRequest, handler);
        }

        
        //确定自定义类型参数的值；还要将请求中的每一个参数赋值给这个对象
        else if (attrName != null) {
            WebDataBinder binder = resolveModelAttribute(attrName, methodParam, implicitModel, webRequest, handler);
            //=====================看后边代码补充============================
            boolean assignBindingResult = (args.length &gt; i + 1 &amp;&amp; Errors.class.isAssignableFrom(paramTypes[i + 1]));
            if (binder.getTarget() != null) {
                doBind(binder, webRequest, validate, validationHints, !assignBindingResult);
            }
            args[i] = binder.getTarget();
            if (assignBindingResult) {
                args[i + 1] = binder.getBindingResult();
                i++;
            }
            implicitModel.putAll(binder.getBindingResult().getModel());
        }
    }
    return args;
}</pre> 
        if (ServletRequest.class.isAssignableFrom(parameterType) ||
                MultipartRequest.class.isAssignableFrom(parameterType)) {
            Object nativeRequest = webRequest.getNativeRequest(parameterType);
            if (nativeRequest == null) {
                throw new IllegalStateException(
                        "Current request is not of type [" + parameterType.getName() + "]: " + request);
            }
            return nativeRequest;
        }
        else if (ServletResponse.class.isAssignableFrom(parameterType)) {
            this.responseArgumentUsed = true;
            Object nativeResponse = webRequest.getNativeResponse(parameterType);
            if (nativeResponse == null) {
                throw new IllegalStateException(
                        "Current response is not of type [" + parameterType.getName() + "]: " + response);
            }
            return nativeResponse;
        }
        else if (HttpSession.class.isAssignableFrom(parameterType)) {
            return request.getSession();
        }
        else if (Principal.class.isAssignableFrom(parameterType)) {
            return request.getUserPrincipal();
        }
        else if (Locale.class.equals(parameterType)) {
            return RequestContextUtils.getLocale(request);
        }
        else if (InputStream.class.isAssignableFrom(parameterType)) {
            return request.getInputStream();
        }
        else if (Reader.class.isAssignableFrom(parameterType)) {
            return request.getReader();
        }
        else if (OutputStream.class.isAssignableFrom(parameterType)) {
            this.responseArgumentUsed = true;
            return response.getOutputStream();
        }
        else if (Writer.class.isAssignableFrom(parameterType)) {
            this.responseArgumentUsed = true;
            return response.getWriter();
        }
        return super.resolveStandardArgument(parameterType, webRequest);
    }</pre> 
    // Bind request parameter onto object...  
    String name = attrName;
 
    if ("".equals(name)) {
           //如果attrName是空串；就将参数类型的首字母小写作为值 
        	//Book book2121 -&gt; name=book
        name = Conventions.getVariableNameForParameter(methodParam);
    }
    Class&lt;?&gt; paramType = methodParam.getParameterType();
    Object bindObject;

	 //确定目标对象的值
    if (implicitModel.containsKey(name)) {
        bindObject = implicitModel.get(name);
    }
    else if (this.methodResolver.isSessionAttribute(name, paramType)) {
        bindObject = this.sessionAttributeStore.retrieveAttribute(webRequest, name);
        if (bindObject == null) {
            raiseSessionRequiredException("Session attribute '" + name + "' required - not found in session");
        }
    }
    else {
        bindObject = BeanUtils.instantiateClass(paramType);
    }


    WebDataBinder binder = createBinder(webRequest, bindObject, name);
    initBinder(handler, name, binder, webRequest);
    return binder;
}</pre> 
      //遍历所有的ViewResolver；
    for (ViewResolver viewResolver : this.viewResolvers) {
        
        
      //viewResolver视图解析器根据方法的返回值，得到一个View对象；
        View view = viewResolver.resolveViewName(viewName, locale);
        
        
        if (view != null) {
            return view;
        }
    }
    return null;
}</pre> 
                    // Ask the subclass to create the View object.
                     //根据方法的返回值创建出视图View对象；
                    view = createView(viewName, locale);
                    
                    
                    if (view == null &amp;&amp; this.cacheUnresolved) {
                        view = UNRESOLVED_VIEW;
                    }
                    if (view != null) {
                        this.viewAccessCache.put(cacheKey, view);
                        this.viewCreationCache.put(cacheKey, view);
                        if (logger.isTraceEnabled()) {
                            logger.trace("Cached view [" + cacheKey + "]");
                        }
                    }
                }
            }
        }
        return (view != UNRESOLVED_VIEW ? view : null);
    }
}</pre> </li><li> <p>创建View对象</p> <p>&nbsp;</p> </li></ul><p>&nbsp;</p> <pre>  @Override
  protected View createView(String viewName, Locale locale) throws Exception {
      // If this resolver is not supposed to handle the given view,
      // return null to pass on to the next resolver in the chain.
      if (!canHandle(viewName, locale)) {
          return null;
      }
      // Check for special "redirect:" prefix.
      if (viewName.startsWith(REDIRECT_URL_PREFIX)) {
          String redirectUrl = viewName.substring(REDIRECT_URL_PREFIX.length());
          RedirectView view = new RedirectView(redirectUrl, isRedirectContextRelative(), isRedirectHttp10Compatible());
          return applyLifecycleMethods(viewName, view);
      }
      // Check for special "forward:" prefix.
      if (viewName.startsWith(FORWARD_URL_PREFIX)) {
          String forwardUrl = viewName.substring(FORWARD_URL_PREFIX.length());
          return new InternalResourceView(forwardUrl);
      }
      // Else fall back to superclass implementation: calling loadView.
      //如果没有前缀就使用父类默认创建一个View；
      return super.createView(viewName, locale);
  }</pre> <p>&nbsp;</p> <p>&nbsp;</p> 
    Map&lt;String, Object&gt; mergedModel = createMergedOutputModel(model, request, response);

    prepareResponse(request, response);
    
    
    //渲染要给页面输出的所有数据
    renderMergedOutputModel(mergedModel, request, response);
}</pre> </li><li> <p>InternalResourceView有这个方法renderMergedOutputModel；</p> <pre>@Override
protected void renderMergedOutputModel(
        Map&lt;String, Object&gt; model, HttpServletRequest request, HttpServletResponse response) throws Exception {

    // Determine which request handle to expose to the RequestDispatcher.
    HttpServletRequest requestToExpose = getRequestToExpose(request);

    // Expose the model object as request attributes.
    
    
    //将模型中的数据放在请求域中
    exposeModelAsRequestAttributes(model, requestToExpose);

    
    
    // Expose helpers as request attributes, if any.
    exposeHelpers(requestToExpose);

    // Determine the path for the request dispatcher.
    String dispatcherPath = prepareForRendering(requestToExpose, response);

    // Obtain a RequestDispatcher for the target resource (typically a JSP).
    RequestDispatcher rd = getRequestDispatcher(requestToExpose, dispatcherPath);
    if (rd == null) {
        throw new ServletException("Could not get RequestDispatcher for [" + getUrl() +
                "]: Check that the corresponding file exists within your web application archive!");
    }

    // If already included or response already committed, perform include, else forward.
    if (useInclude(requestToExpose, response)) {
        response.setContentType(getContentType());
        if (logger.isDebugEnabled()) {
            logger.debug("Including resource [" + getUrl() + "] in InternalResourceView '" + getBeanName() + "'");
        }
        rd.include(requestToExpose, response);
    }

    else {
        // Note: The forwarded resource is supposed to determine the content type itself.
        if (logger.isDebugEnabled()) {
            logger.debug("Forwarding to resource [" + getUrl() + "] in InternalResourceView '" + getBeanName() + "'");
        }
        
        //转发页面
        rd.forward(requestToExpose, response);
    }
}</pre> </li><li> <p>将模型中的所有数据取出来全放在request域中</p> <pre>protected void exposeModelAsRequestAttributes(Map&lt;String, Object&gt; model, HttpServletRequest request) throws Exception {
    for (Map.Entry&lt;String, Object&gt; entry : model.entrySet()) {
        String modelName = entry.getKey();
        Object modelValue = entry.getValue();
        if (modelValue != null) {
            
            //将ModelMap中的数据放到请求域中
            request.setAttribute(modelName, modelValue);
            
            
            if (logger.isDebugEnabled()) {
                logger.debug("Added model object '" + modelName + "' of type [" + modelValue.getClass().getName() +
                        "] to request in view with name '" + getBeanName() + "'");
            }
        }
        else {
            request.removeAttribute(modelName);
            if (logger.isDebugEnabled()) {
                logger.debug("Removed model object '" + modelName +
                        "' from request in view with name '" + getBeanName() + "'");
            }
        }
    }
}</pre> <p>总结：</p> 
<ul><li> <p>视图解析器只是为了得到视图对象</p> </li><li> <p>视图对象才能真正的转发（将模型数据全部放在请求域中）或者重定向到页面视图对象才能真正的渲染视图</p> </li></ul></li><li> <p>ViewResolver</p> <p>&nbsp;</p> </li><li> <p>View:</p> <p>&nbsp;</p> </li></ul></li></ol>
<fmt:setLocale>
<fmt:setBundle>
<fmt:message>
<fmt:message>
mvc:view-controller
public void render(Map&lt;String, ?&gt; model, HttpServletRequest request, HttpServletResponse response) throws Exception {
    System.out.println("保存的数据："+model);
    response.getWriter().write("即将展现内容:");
}
private Integer order = 0;

public View resolveViewName(String viewName, Locale locale) throws Exception {
    if (viewName.startsWith("myView:")) {
        return new MyView();
    } else {
        return null;
    }
}

public int getOrder() {
    return this.order;
}

public void setOrder(Integer order) {
    this.order = order;
}
&lt;context:component-scan base-package="com.chenhui"&gt;&lt;/context:component-scan&gt;

&lt;bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"&gt;
    &lt;property name="prefix" value="/WEB-INF/pages/"&gt;&lt;/property&gt;
    &lt;property name="suffix" value=".jsp"&gt;&lt;/property&gt;
&lt;/bean&gt;
&lt;servlet&gt;
    &lt;servlet-name&gt;dispatcherServlet&lt;/servlet-name&gt;
    &lt;servlet-class&gt;org.springframework.web.servlet.DispatcherServlet&lt;/servlet-class&gt;
    &lt;init-param&gt;
        &lt;param-name&gt;contextConfigLocation&lt;/param-name&gt;
        &lt;param-value&gt;classpath:ioc.xml&lt;/param-value&gt;
    &lt;/init-param&gt;
    &lt;load-on-startup&gt;1&lt;/load-on-startup&gt;
&lt;/servlet&gt;
&lt;servlet-mapping&gt;
    &lt;servlet-name&gt;dispatcherServlet&lt;/servlet-name&gt;
    &lt;url-pattern&gt;/&lt;/url-pattern&gt;
&lt;/servlet-mapping&gt;

&lt;filter&gt;
    &lt;filter-name&gt;CharacterEncodingFilter&lt;/filter-name&gt;
    &lt;filter-class&gt;org.springframework.web.filter.CharacterEncodingFilter&lt;/filter-class&gt;
    &lt;init-param&gt;
        &lt;param-name&gt;encoding&lt;/param-name&gt;
        &lt;param-value&gt;UTF-8&lt;/param-value&gt;
    &lt;/init-param&gt;
    &lt;init-param&gt;
        &lt;param-name&gt;forceEncoding&lt;/param-name&gt;
        &lt;param-value&gt;true&lt;/param-value&gt;
    &lt;/init-param&gt;
&lt;/filter&gt;
&lt;filter-mapping&gt;
    &lt;filter-name&gt;CharacterEncodingFilter&lt;/filter-name&gt;
    &lt;url-pattern&gt;/*&lt;/url-pattern&gt;
&lt;/filter-mapping&gt;

&lt;filter&gt;
    &lt;filter-name&gt;HiddenHttpMethodFilter&lt;/filter-name&gt;
    &lt;filter-class&gt;org.springframework.web.filter.HiddenHttpMethodFilter&lt;/filter-class&gt;
&lt;/filter&gt;
&lt;filter-mapping&gt;
    &lt;filter-name&gt;HiddenHttpMethodFilter&lt;/filter-name&gt;
    &lt;url-pattern&gt;/*&lt;/url-pattern&gt;
&lt;/filter-mapping&gt;
private Integer id;
private String lastName;

private String email;
//1 male, 0 female
private Integer gender;

private Department department;

public Integer getId() {
    return id;
}

public void setId(Integer id) {
    this.id = id;
}

public String getLastName() {
    return lastName;
}

public void setLastName(String lastName) {
    this.lastName = lastName;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public Integer getGender() {
    return gender;
}

public void setGender(Integer gender) {
    this.gender = gender;
}

public Department getDepartment() {
    return department;
}

public void setDepartment(Department department) {
    this.department = department;
}

public Employee(Integer id, String lastName, String email, Integer gender,
                Department department) {
    super();
    this.id = id;
    this.lastName = lastName;
    this.email = email;
    this.gender = gender;
    this.department = department;
}

public Employee() {
}

@Override
public String toString() {
    return "Employee [id=" + id + ", lastName=" + lastName + ", email="
            + email + ", gender=" + gender + ", department=" + department
            + "]";
}
private Integer id;
private String lastName;

private String email;
//1 male, 0 female
private Integer gender;

private Department department;

public Integer getId() {
    return id;
}

public void setId(Integer id) {
    this.id = id;
}

public String getLastName() {
    return lastName;
}

public void setLastName(String lastName) {
    this.lastName = lastName;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public Integer getGender() {
    return gender;
}

public void setGender(Integer gender) {
    this.gender = gender;
}

public Department getDepartment() {
    return department;
}

public void setDepartment(Department department) {
    this.department = department;
}

public Employee(Integer id, String lastName, String email, Integer gender,
                Department department) {
    super();
    this.id = id;
    this.lastName = lastName;
    this.email = email;
    this.gender = gender;
    this.department = department;
}

public Employee() {
}

@Override
public String toString() {
    return "Employee [id=" + id + ", lastName=" + lastName + ", email="
            + email + ", gender=" + gender + ", department=" + department
            + "]";
}
private static Map&lt;Integer, Department&gt; departments = null;

static{
    departments = new HashMap&lt;Integer, Department&gt;();

    departments.put(101, new Department(101, "D-AA"));
    departments.put(102, new Department(102, "D-BB"));
    departments.put(103, new Department(103, "D-CC"));
    departments.put(104, new Department(104, "D-DD"));
    departments.put(105, new Department(105, "D-EE"));
}

public Collection&lt;Department&gt; getDepartments(){
    return departments.values();
}

public Department getDepartment(Integer id){
    return departments.get(id);
}
private static Map&lt;Integer, Employee&gt; employees = null;

@Autowired
private DepartmentDao departmentDao;

static{
    employees = new HashMap&lt;Integer, Employee&gt;();

    employees.put(1001, new Employee(1001, "E-AA", "aa@163.com", 1, new Department(101, "D-AA")));
    employees.put(1002, new Employee(1002, "E-BB", "bb@163.com", 1, new Department(102, "D-BB")));
    employees.put(1003, new Employee(1003, "E-CC", "cc@163.com", 0, new Department(103, "D-CC")));
    employees.put(1004, new Employee(1004, "E-DD", "dd@163.com", 0, new Department(104, "D-DD")));
    employees.put(1005, new Employee(1005, "E-EE", "ee@163.com", 1, new Department(105, "D-EE")));
}

private static Integer initId = 1006;

public void save(Employee employee){
    if(employee.getId() == null){
        employee.setId(initId++);
    }

    employee.setDepartment(departmentDao.getDepartment(employee.getDepartment().getId()));
    employees.put(employee.getId(), employee);
}

public Collection&lt;Employee&gt; getAll(){
    return employees.values();
}

public Employee get(Integer id){
    return employees.get(id);
}

public void delete(Integer id){
    employees.remove(id);
}
@Autowired
EmployeeDao employees;

@Autowired
DepartmentDao departments;

@RequestMapping(value = "/emp", method = RequestMethod.GET)
public String getEmps(Model model) {
    Collection&lt;Employee&gt; all = employees.getAll();
    model.addAttribute("emps", all);
    return "list";
}

@RequestMapping(value = "/emp", method = RequestMethod.POST)
public String addEmp(Employee employee, Model model) {

    employees.save(employee);

    return "redirect:/emp";
}

@RequestMapping(value = "/emp/{id}", method = RequestMethod.GET)
public String getEmp(@PathVariable("id") Integer id, Model model) {
    Employee employee = employees.get(id);
    Collection&lt;Department&gt; departments = this.departments.getDepartments();
    //此处给spring表单添加一个employee对象，以免发生command未找到的异常
    model.addAttribute("employee", employee);
    model.addAttribute("departments", departments);
    return "editEmp";
}

@RequestMapping(value = "/emp/{id}", method = RequestMethod.PUT)
public String updateEmp(@ModelAttribute("employee") Employee employee, @PathVariable("id") Integer integer) {
    System.out.println("要修改的：" + employee);
    employees.save(employee);
    return "redirect:/emp";
}

@RequestMapping(value = "/emp/{id}", method = RequestMethod.DELETE)
public String deleteEmp(@PathVariable("id") Integer id) {
    employees.delete(id);
    return "redirect:/emp";
}

@ModelAttribute
public void myMethodAttribute(@RequestParam(value = "id", required = false) Integer id, Model model) {
    System.out.println("modelAttribute");
    if (id != null) {
        Employee employee = employees.get(id);
        model.addAttribute("employee", employee);
    }

}


@RequestMapping("/toaddpage")
public String toAddPage(Model model) {
    Collection&lt;Department&gt; all = departments.getDepartments();

    model.addAttribute("departments", all);
    model.addAttribute("command", new Employee());
    return "addEmp";
}
    private Department department;--%&gt;
&lt;thead&gt;
&lt;tr&gt;
    &lt;th&gt;ID&lt;/th&gt;
    &lt;th&gt;lastName&lt;/th&gt;
    &lt;th&gt;email&lt;/th&gt;
    &lt;th&gt;gender&lt;/th&gt;
    &lt;th&gt;departmentName&lt;/th&gt;
    &lt;th&gt;EDIT&lt;/th&gt;
    &lt;th&gt;DELETE&lt;/th&gt;
&lt;/tr&gt;
&lt;/thead&gt;
&lt;tbody&gt;
&lt;c:forEach items="${emps}" var="emp"&gt;
    &lt;tr&gt;
        &lt;td&gt;${emp.id}&lt;/td&gt;
        &lt;td&gt;${emp.lastName}&lt;/td&gt;
        &lt;td&gt;${emp.email}&lt;/td&gt;
        &lt;td&gt;${emp.gender==0?"女":"男"}&lt;/td&gt;
        &lt;td&gt;${emp.department.departmentName}&lt;/td&gt;
        &lt;td&gt;&lt;a href="${ctp}/emp/${emp.id}"&gt;修改&lt;/a&gt;&lt;/td&gt;
        &lt;!--删除操作可以绑定单击事件，使用ajax发送delete请求--&gt;
        &lt;td&gt;
            &lt;form action="${ctp}/emp/${emp.id}" method="post"&gt;
                &lt;input type="hidden" name="_method" value="DELETE"&gt;
                &lt;input type="submit" value="delete"&gt;
            &lt;/form&gt;
        &lt;/td&gt;
    &lt;/tr&gt;
&lt;/c:forEach&gt;
&lt;/tbody&gt;
    model.addAttribute("departments", all);
    model.addAttribute("command", new Employee());
    return "addEmp";
}</pre> 
姓名：&lt;form:input path="lastName"&gt;&lt;/form:input&gt;&lt;br&gt;
邮箱：&lt;form:input path="email"&gt;&lt;/form:input&gt;&lt;br&gt;
性别：&lt;br&gt;
男：&lt;form:radiobutton path="gender" value="1"&gt;&lt;/form:radiobutton&gt;
女：&lt;form:radiobutton path="gender" value="0"&gt;&lt;/form:radiobutton&gt;&lt;br&gt;
部门：
&lt;form:select path="department.id" items="${departments}"
             itemLabel="departmentName" itemValue="id"&gt;
&lt;/form:select&gt;
&lt;input type="submit" value="修改"&gt;
	//WebDataBinder
    WebDataBinder binder = binderFactory.createBinder(request, attribute, name);


    if (binder.getTarget() != null) {
        
           //将页面提交过来的数据封装到javaBean的属性中
        bindRequestParameters(binder, request);
           //+++++++++
        
        validateIfApplicable(binder, parameter);
        if (binder.getBindingResult().hasErrors()) {
            if (isBindExceptionRequired(binder, parameter)) {
                throw new BindException(binder.getBindingResult());
            }
        }
    }
@Autowired
DepartmentDao departmentDao;

public Employee convert(String source) {
    System.out.println("将要转换的字符串" + source);
    Employee employee = new Employee();
    if (source.contains("-")) {
        String[] split = source.split("-");
        employee.setLastName(split[0]);
        employee.setEmail(split[1]);
        employee.setGender(Integer.parseInt(split[2]));
        employee.setDepartment(departmentDao.getDepartment(Integer.parseInt(split[3])));
    }
    return employee;
}
<mvc:default-servlet-handler/>
<mvc:annotation-driven/>
<mvc:default-servlet-handler/>
<mvc:annotation-driven/>
<mvc:annotation-driven/>
    &lt;dependency&gt;
        &lt;groupId&gt;org.hibernate&lt;/groupId&gt;
        &lt;artifactId&gt;hibernate-validator&lt;/artifactId&gt;
        &lt;version&gt;5.4.1.Final&lt;/version&gt;
    &lt;/dependency&gt;
    &lt;dependency&gt;
        &lt;groupId&gt;org.jboss.logging&lt;/groupId&gt;
        &lt;artifactId&gt;jboss-logging&lt;/artifactId&gt;
        &lt;version&gt;3.3.0.Final&lt;/version&gt;
    &lt;/dependency&gt;
    &lt;dependency&gt;
        &lt;groupId&gt;com.fasterxml&lt;/groupId&gt;
        &lt;artifactId&gt;classmate&lt;/artifactId&gt;
        &lt;version&gt;1.3.3&lt;/version&gt;
    &lt;/dependency&gt;</pre> 
@DateTimeFormat(pattern = "yyyy-MM-dd")
@Past
private Date birth;
    if (result.hasErrors()){
        System.out.println("有校验错误");
        return "addEmp";
    }else{
        employees.save(employee);
    }


    return "redirect:/emp";
}</pre> 
@ResponseBody
@RequestMapping("/getallajax")
public Collection&lt;Employee&gt; ajaxGetAll() {
    Collection&lt;Employee&gt; all = employeeDao.getAll();
    return all;
}
private String email;
//1 male, 0 female

private Integer gender;

@JsonIgnore
private Department department;</pre> <p>输入：</p> <p>&nbsp;</p> <p>结果：</p> <p>&nbsp;</p> </li></ul>
    System.out.println("上传信息");
    System.out.println("文件名"+file.getName());
    System.out.println("文件初始名"+file.getOriginalFilename());

    try {
        file.transferTo(new File("D:\\upload\\"+file.getOriginalFilename()));
        model.addAttribute("message","文件上传成功");
    } catch (IOException e) {
        e.printStackTrace();
        model.addAttribute("message","文件上传失败"+e.getCause());
    }

    return "list";

}
    for(MultipartFile file: files){
        
        System.out.println("上传信息");
        System.out.println("文件名"+file.getName());
        System.out.println("文件初始名"+file.getOriginalFilename());
		if(!file.isEmpty()){
            try {
                file.transferTo(new File("D:\\upload\\"+file.getOriginalFilename()));
                model.addAttribute("message","文件上传成功");
            } catch (IOException e) {
                e.printStackTrace();
                model.addAttribute("message","文件上传失败"+e.getCause());
            }
        }
        return "list";                       
    }       
}
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    System.out.println("MyFirstInterceptor...preHandle");
    return true;
}

public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    System.out.println("MyFirstInterceptor...postHandle");
}

public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    System.out.println("MyFirstInterceptor...afterCompletion");
}
    &lt;!--拦截具体请求↓--&gt;
    &lt;mvc:interceptor&gt;
        &lt;!--只拦截path所对应的请求--&gt;
        &lt;mvc:mapping path="/testInter"/&gt;
        &lt;bean class="com.chenhui.interceptor.MyFirstInterceptor"&gt;&lt;/bean&gt;
    &lt;/mvc:interceptor&gt;
&lt;/mvc:interceptors&gt;</pre> <p>testInter控制器如下</p> <pre>@Controller
@RequestMapping("/testInter")
public String testInterceptor(){
    return "hello";
}
        try {
            processedRequest = checkMultipart(request);
            multipartRequestParsed = processedRequest != request;

            
            // Determine handler for the current request.拿到方法的执行链，包含拦截器
            mappedHandler = getHandler(processedRequest);
            
            
            
            if (mappedHandler == null || mappedHandler.getHandler() == null) {
                noHandlerFound(processedRequest, response);
                return;
            }

            
            // Determine handler adapter for the current request.
            HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

            // Process last-modified header, if supported by the handler.
            String method = request.getMethod();
            boolean isGet = "GET".equals(method);
            if (isGet || "HEAD".equals(method)) {
                long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
                if (logger.isDebugEnabled()) {
                    String requestUri = urlPathHelper.getRequestUri(request);
                    logger.debug("Last-Modified value for [" + requestUri + "] is: " + lastModified);
                }
                if (new ServletWebRequest(request, response).checkNotModified(lastModified) &amp;&amp; isGet) {
                    return;
                }
            }

            
            
           //拦截器preHandle执行位置;有一个拦截器返回false目标方法以后都不会执行；直接跳到afterCompletion
            if (!mappedHandler.applyPreHandle(processedRequest, response)) {
                return;
            }

            
            
            try {
                // Actually invoke the handler.适配器执行目标方法
                mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
            }
            finally {
                if (asyncManager.isConcurrentHandlingStarted()) {
                    return;
                }
            }

            applyDefaultViewName(request, mv);
            
            
            
             //目标方法只要正常就会走到postHandle;任何期间有异常
            mappedHandler.applyPostHandle(processedRequest, response, mv);
            
            
            
        }
        catch (Exception ex) {
            dispatchException = ex;
        }



        //页面渲染；如果完蛋也是直接跳到afterCompletion；
        processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);



    }
    catch (Exception ex) {
        triggerAfterCompletion(processedRequest, response, mappedHandler, ex);
    }
    catch (Error err) {
        triggerAfterCompletionWithError(processedRequest, response, mappedHandler, err);
    }
    finally {
        if (asyncManager.isConcurrentHandlingStarted()) {
            // Instead of postHandle and afterCompletion
            mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response);
            return;
        }
        // Clean up any resources used by a multipart request.
        if (multipartRequestParsed) {
            cleanupMultipart(processedRequest);
        }
    }
}</pre> 
            //preHandle-true-false
            if (!interceptor.preHandle(request, response, this.handler)) {
                //执行完afterCompletion（）;
                triggerAfterCompletion(request, response, null);
                //返回一个false
                return false;
            }
           //记录一下索引
           //this.interceptorIndex = i;
        }
    }
    return true;
}</pre> 
    boolean errorView = false;

    if (exception != null) {
        if (exception instanceof ModelAndViewDefiningException) {
            logger.debug("ModelAndViewDefiningException encountered", exception);
            mv = ((ModelAndViewDefiningException) exception).getModelAndView();
        }
        else {
            Object handler = (mappedHandler != null ? mappedHandler.getHandler() : null);
            mv = processHandlerException(request, response, handler, exception);
            errorView = (mv != null);
        }
    }

    // Did the handler return a view to render?
    if (mv != null &amp;&amp; !mv.wasCleared()) {
        
         //页面渲染
        render(mv, request, response);
        if (errorView) {
            WebUtils.clearErrorRequestAttributes(request);
        }
    }
    else {
        if (logger.isDebugEnabled()) {
            logger.debug("Null ModelAndView returned to DispatcherServlet with name '" + getServletName() +
                    "': assuming HandlerAdapter completed request handling");
        }
    }

    if (WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) {
        // Concurrent handling started during a forward
        return;
    }


    if (mappedHandler != null) {
           //页面正常执行afterCompletion；即使没走到这，afterCompletion总会执行；
        mappedHandler.triggerAfterCompletion(request, response, null);
    }
}</pre> 
    if (getInterceptors() == null) {
        return;
    }
     
      //有记录最后一个放行拦截器的索引，从他开始把之前所有放行的拦截器的afterCompletion都执行
    for (int i = this.interceptorIndex; i &gt;= 0; i--) {
        HandlerInterceptor interceptor = getInterceptors()[i];
        try {
            interceptor.afterCompletion(request, response, this.handler, ex);
        }
        catch (Throwable ex2) {
            logger.error("HandlerInterceptor.afterCompletion threw exception", ex2);
        }
    }
}</pre> 
    String locale = request.getParameter("locale");
    System.out.println("自己区域解析器接受的locale:"+locale);
    if (locale != null &amp;&amp; !"".equals(locale)) {
        l = new Locale(locale.split("_")[0], locale.split("_")[1]);
    } else {
        l = request.getLocale();
    }
    System.out.println("Locale:"+l.toString());
    return l;
}

public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {
    throw new UnsupportedOperationException("Can't set Locale message");
}
@Override
public LocaleContext resolveLocaleContext(HttpServletRequest request) {
    return new TimeZoneAwareLocaleContext() {
        @Override
        public Locale getLocale() {
            return getDefaultLocale();
        }
        @Override
        public TimeZone getTimeZone() {
            return getDefaultTimeZone();
        }
    };
}

@Override
public void setLocaleContext(HttpServletRequest request, HttpServletResponse response, LocaleContext localeContext) {
    throw new UnsupportedOperationException("Cannot change fixed locale - use a different locale resolution strategy");
}</pre> 
    boolean errorView = false;

	//如果有异常
    if (exception != null) {
        if (exception instanceof ModelAndViewDefiningException) {
            logger.debug("ModelAndViewDefiningException encountered", exception);
            mv = ((ModelAndViewDefiningException) exception).getModelAndView();
        }
        else {
            
            //处理异常
            Object handler = (mappedHandler != null ? mappedHandler.getHandler() : null);
            
            //===================================
            mv = processHandlerException(request, response, handler, exception);
            
            
            errorView = (mv != null);
        }
    }

    // Did the handler return a view to render?
    if (mv != null &amp;&amp; !mv.wasCleared()) {
           //来到页面
        render(mv, request, response);
        if (errorView) {
            WebUtils.clearErrorRequestAttributes(request);
        }
    }
    else {
        if (logger.isDebugEnabled()) {
            logger.debug("Null ModelAndView returned to DispatcherServlet with name '" + getServletName() +
                    "': assuming HandlerAdapter completed request handling");
        }
    }

    if (WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) {
        
        // Concurrent handling started during a forward
        return;
    }

    if (mappedHandler != null) {
        mappedHandler.triggerAfterCompletion(request, response, null);
    }
}</pre> 
    // Check registered HandlerExceptionResolvers...
    ModelAndView exMv = null;
    for (HandlerExceptionResolver handlerExceptionResolver : this.handlerExceptionResolvers) {
        exMv = handlerExceptionResolver.resolveException(request, response, handler, ex);
        if (exMv != null) {
            break;
        }
    }
    if (exMv != null) {
        if (exMv.isEmpty()) {
            return null;
        }
        
        // We might still need view name translation for a plain error model...
        if (!exMv.hasView()) {
            exMv.setViewName(getDefaultViewName(request));
        }
        if (logger.isDebugEnabled()) {
            logger.debug("Handler execution resulted in exception - forwarding to resolved error view: " + exMv, ex);
        }
        WebUtils.exposeErrorRequestAttributes(request, ex, getServletName());
        return exMv;
    }

    throw ex;
}
@ExceptionHandler(value = {ArithmeticException.class})
public String handleException01(){
    System.out.println("handleException-Arithmetic");
    return "myError";
}
    }
    System.out.println("登陆成功");
    return "success";
}</pre> 

__EOF__

本文作者：Curryxin
本文链接：https://www.cnblogs.com/Curryxin/p/15023785.html
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