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

1.HandlerAdapter

0-支持方法上標(biāo)注@RequestMapping1-支持函數(shù)式編程的xxxx

2.執(zhí)行目標(biāo)方法

3.參數(shù)解析器:確定要執(zhí)行的目標(biāo)方法每一個參數(shù)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(shù)類型, 如果支持, 就調(diào)用resolveArgument解析方法

4.返回值處理器

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

請求進(jìn)來后, 首先從handlerMapping中查找是否有對應(yīng)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(shù)類型是否匹配,首先獲得方法中聲明的參數(shù)名字, 放到數(shù)組里,循環(huán)遍歷27種解析器判斷是否有支持處理對應(yīng)參數(shù)名字類型的解析器,如果有的話,根據(jù)名字進(jìn)行解析參數(shù),根據(jù)名字獲得域數(shù)據(jù)中的參數(shù), 循環(huán)每個參數(shù)名字進(jìn)行判斷, 從而為每個參數(shù)進(jìn)行賦值.

對于自定義的POJO類參數(shù):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(shù)據(jù)綁定器,將請求參數(shù)的值綁定到指定的javaBean里面WebDataBinder 利用它里面的Converters將請求數(shù)據(jù)轉(zhuǎn)成指定的數(shù)據(jù)類型,通過反射一系列操作,再次封裝到j(luò)avabean中

GenericConversionService:在設(shè)置每一個值的時候,找它里面所有的converter哪個可以將這個數(shù)據(jù)類型(request帶來參數(shù)的字符串)轉(zhuǎn)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(zhuǎn)換器:實(shí)現(xiàn)按照自己的規(guī)則給相應(yīng)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(fù)雜參數(shù)

Map/Model(map/model里面的數(shù)據(jù)會被放在request的請求域 相當(dāng)于request.setAttribute)/Errors/BindingResult/RedirectAttributes(重定向攜帶數(shù)據(jù))/ServletRespons().SessionStaus.UriComponentsBuilder

6.在上面第五步目標(biāo)方法執(zhí)行完成后:將所有的數(shù)據(jù)都放在ModelAdnViewContainer;包含要去的頁面地址View,還包含Model數(shù)據(jù)

7.處理派發(fā)結(jié)果

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

在頁面進(jìn)行響應(yīng)前, 進(jìn)行視圖渲染的時候:exposeModelAsRequestAttributes(model, request); 該方法將model中所有參數(shù)都放在請求域數(shù)據(jù)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(huán)遍歷model中的所有數(shù)據(jù)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M(jìn)olde 最終在底層源碼都是同一個對象在mvcContainer容器中進(jìn)行保存

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