HandlerMapping中找到能處理請求的Handler(Controller,method())為當前Handler找一個適配器HandlerAdapter:RequestMappingHandlerAdapter

1.HandlerAdapter

0-支持方法上標注@RequestMapping1-支持函數式編程的xxxx

2.執行目標方法

3.參數解析器:確定要執行的目標方法每一個參數的值是什么

boolean supportsParameter(MethodParameter parameter);Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,先判斷是否支持該參數類型, 如果支持, 就調用resolveArgument解析方法

4.返回值處理器

5.挨個判斷所有參數解析器哪個支持這個參數:HandlerMethodArgumentResolver: 把控著支持的方法參數類型

請求進來后, 首先從handlerMapping中查找是否有對應的映射處理, 得到映射適配器Adapter,再通過適配器,查找有哪些方法匹配請求,首先判斷方法名,以及參數類型是否匹配,首先獲得方法中聲明的參數名字, 放到數組里,循環遍歷27種解析器判斷是否有支持處理對應參數名字類型的解析器,如果有的話,根據名字進行解析參數,根據名字獲得域數據中的參數, 循環每個參數名字進行判斷, 從而為每個參數進行賦值.

對于自定義的POJO類參數:ServletRequestMethodArgumentResolver 這個解析器用來解析: 是通過主要是通過判斷是否是簡單類型得到的

@Overridepublic boolean supportsParameter(MethodParameter parameter) {return (parameter.hasParameterAnnotation(ModelAttribute.class) ||(this.annotationNotRequired && !BeanUtils.isSimpleProperty(parameter.getParameterType())));}public static boolean isSimpleValueType(Class<?> type) {return (Void.class != type && void.class != type &&(ClassUtils.isPrimitiveOrWrapper(type) ||Enum.class.isAssignableFrom(type) ||CharSequence.class.isAssignableFrom(type) ||Number.class.isAssignableFrom(type) ||Date.class.isAssignableFrom(type) ||Temporal.class.isAssignableFrom(type) ||URI.class == type ||URL.class == type ||Locale.class == type ||Class.class == type));}public final Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {Assert.state(mavContainer != null, 'ModelAttributeMethodProcessor requires ModelAndViewContainer');Assert.state(binderFactory != null, 'ModelAttributeMethodProcessor requires WebDataBinderFactory');String name = ModelFactory.getNameForParameter(parameter);ModelAttribute ann = parameter.getParameterAnnotation(ModelAttribute.class);if (ann != null) {mavContainer.setBinding(name, ann.binding());}Object attribute = null;BindingResult bindingResult = null;if (mavContainer.containsAttribute(name)) {attribute = mavContainer.getModel().get(name);}else {// Create attribute instancetry {attribute = createAttribute(name, parameter, binderFactory, webRequest);}catch (BindException ex) {if (isBindExceptionRequired(parameter)) {// No BindingResult parameter -> fail with BindExceptionthrow ex;}// Otherwise, expose null/empty value and associated BindingResultif (parameter.getParameterType() == Optional.class) {attribute = Optional.empty();}else {attribute = ex.getTarget();}bindingResult = ex.getBindingResult();}}if (bindingResult == null) {// Bean property binding and validation;// skipped in case of binding failure on construction.WebDataBinder binder = binderFactory.createBinder(webRequest, attribute, name);if (binder.getTarget() != null) {if (!mavContainer.isBindingDisabled(name)) {bindRequestParameters(binder, webRequest);}validateIfApplicable(binder, parameter);if (binder.getBindingResult().hasErrors() && isBindExceptionRequired(binder, parameter)) {throw new BindException(binder.getBindingResult());}}// Value type adaptation, also covering java.util.Optionalif (!parameter.getParameterType().isInstance(attribute)) {attribute = binder.convertIfNecessary(binder.getTarget(), parameter.getParameterType(), parameter);}bindingResult = binder.getBindingResult();}// Add resolved attribute and BindingResult at the end of the modelMap<String, Object> bindingResultModel = bindingResult.getModel();mavContainer.removeAttributes(bindingResultModel);mavContainer.addAllAttributes(bindingResultModel);return attribute;}

WebDataBinder binder =binderFactory.createBinder(webRequest,attribute,name)WebDataBinder:web數據綁定器,將請求參數的值綁定到指定的javaBean里面WebDataBinder 利用它里面的Converters將請求數據轉成指定的數據類型,通過反射一系列操作,再次封裝到javabean中

GenericConversionService:在設置每一個值的時候,找它里面所有的converter哪個可以將這個數據類型(request帶來參數的字符串)轉換到指定的類型(javabean—某一個類型)

未來我們可以給WebDataBinder里面放自己的Converter

private static final class StringToNumber implements Converter<String, T> {converter總接口:@FunctionalInterfacepublic interface Converter<S, T> {

//自定義轉換器:實現按照自己的規則給相應對象賦值

@Override public void addFormatters(FormatterRegistry registry) { registry.addConverter(new Converter<String, Pet>() {@Overridepublic Pet convert(String source) { if (!StringUtils.isEmpty(source)){Pet pet = new Pet();String[] split = source.split(',');pet.setName(split[0]);pet.setAge(split[1]);return pet; } return null;} }); }二:復雜參數

Map/Model(map/model里面的數據會被放在request的請求域 相當于request.setAttribute)/Errors/BindingResult/RedirectAttributes(重定向攜帶數據)/ServletRespons().SessionStaus.UriComponentsBuilder

6.在上面第五步目標方法執行完成后:將所有的數據都放在ModelAdnViewContainer;包含要去的頁面地址View,還包含Model數據

7.處理派發結果

processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);

在頁面進行響應前, 進行視圖渲染的時候:exposeModelAsRequestAttributes(model, request); 該方法將model中所有參數都放在請求域數據中

protected void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception {// Expose the model object as request attributes.exposeModelAsRequestAttributes(model, request);// Expose helpers as request attributes, if any.exposeHelpers(request);// Determine the path for the request dispatcher.String dispatcherPath = prepareForRendering(request, response);// Obtain a RequestDispatcher for the target resource (typically a JSP).RequestDispatcher rd = getRequestDispatcher(request, 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(request, response)) {response.setContentType(getContentType());if (logger.isDebugEnabled()) {logger.debug('Including [' + getUrl() + ']');}rd.include(request, response);}else {// Note: The forwarded resource is supposed to determine the content type itself.if (logger.isDebugEnabled()) {logger.debug('Forwarding to [' + getUrl() + ']');}rd.forward(request, response);}}

通過循環遍歷model中的所有數據放在請求域中

protected void exposeModelAsRequestAttributes(Map<String, Object> model,HttpServletRequest request) throws Exception {model.forEach((name, value) -> {if (value != null) {request.setAttribute(name, value);}else {request.removeAttribute(name);}});}

不管我們在方法形參位置放 Map集合或者Molde 最終在底層源碼都是同一個對象在mvcContainer容器中進行保存

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