标签：determine gets win 处理流程 后台 查找 exp request对象 isa
MVC思想? 模型-视图-控制器（MVC）是一个众所周知的以设计界面应用程序为基础的设计思想。它主要通过分离模型、视图及控制器在应用程序中的角色将业务逻辑从界面中解耦。通常，模型负责封装应用程序数据在视图层展示。视图仅仅只是展示这些数据，不包含任何业务逻辑。控制器负责接收来自用户的请求，并调用后台服务（service或者dao）来处理业务逻辑。处理后，后台业务层可能会返回了一些数据在视图层展示。控制器收集这些数据及准备模型在视图层展示。MVC模式的核心思想是将业务逻辑从界面中分离出来，允许它们单独改变而不会相互影响。
Spring MVC框架也是一个基于请求驱动的Web框架，并且使用了前端控制器模式（是用来提供一个集中的请求处理机制，所有的请求都将由一个单一的处理程序处理来进行设计，再根据请求映射规则分发给相应的页面控制器（动作/处理器）进行处理。首先让我们整体看一下Spring MVC处理请求的流程：
首先用户发送请求,请求被SpringMvc前端控制器（DispatherServlet）捕获；
前端控制器(DispatherServlet)对请求URL解析获取请求URI,根据URI, 调用HandlerMapping；
前端控制器(DispatherServlet)获得返回的HandlerExecutionChain（包括Handler对象以及Handler对象对应的拦截器）；
DispatcherServlet 根据获得的HandlerExecutionChain，选择一个合适的HandlerAdapter。（附注：如果成功获得HandlerAdapter后，此时将开始执行拦截器的preHandler(...)方法）；
HandlerAdapter根据请求的Handler适配并执行对应的Handler；HandlerAdapter(提取Request中的模型数据，填充Handler入参，开始执行Handler（Controller)。 在填充Handler的入参过程中，根据配置，Spring将做一些额外的工作：
HttpMessageConveter： 将请求消息（如Json、xml等数据）转换成一个对象，将对象转换为指定的响应信息。
数据转换：对请求消息进行数据转换。如String转换成Integer、Double等数据格式化：
数据格式化。 如将字符串转换成格式化数字或格式化日期等
数据验证： 验证数据的有效性（长度、格式等），验证结果存储到BindingResult或Error中）
Handler执行完毕，返回一个ModelAndView(即模型和视图)给HandlerAdaptor
HandlerAdaptor适配器将执行结果ModelAndView返回给前端控制器。
前端控制器接收到ModelAndView后，请求对应的视图解析器。
视图解析器解析ModelAndView后返回对应View;
11、最终前端控制器将渲染后的页面响应给用户或客户端
? 对于SpringMvc 项目所有的请求入口(静态资源除外)这里都是从web.xml文件配置的前端控制器DispatcherServlet开始，
<!-- servlet请求分发器 -->
<servlet>
<servlet-name>springMvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:servlet-context.xml</param-value>
</init-param>
<!-- 表示启动容器时初始化该Servlet -->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springMvc</servlet-name>
<!-- 这是拦截请求, /代表拦截所有请求,拦截所有.do请求 -->
<url-pattern>/</url-pattern>
</servlet-mapping>DispatcherServlet UML继承关系图如下:
这里关注蓝线部分继承结构:DispatcherServlet-->FrameworkServlet-->HttpServletBean-->HttpServlet-->GenericServlet-->Servlet,对于请求核心时序图如下:
对于web 请求的处理，大家都知道是通过继承HttpServlet重写其service方法，这里打开DispatcherServlet源码发现这里并没有看到我们要找的service方法，此时到父类FrameworkServlet 查找如下:可以看到父类重写HttpServlet service方法。
/**
* Override the parent class implementation in order to intercept PATCH requests.
*/
@Override
protected void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpMethod httpMethod = HttpMethod.resolve(request.getMethod());
if (httpMethod == HttpMethod.PATCH || httpMethod == null) {
proce***equest(request, response);
}
else {
super.service(request, response);
}
}? 从源码分析来看当请求方法为patch请求或者为null时执行proce***equest 方法，其他情况则调用父类service 方法，大家都知道SpringMvc 请求大多请求是get|post请求为主，此时继续向上查看FrameworkServlet 父类HttpServletBean（抽象类继承HttpServlet 并未重写service方法 所以向上继续寻找)-->HttpServlet service 方法
@Override
public void service(ServletRequest req, ServletResponse res)
throws ServletException, IOException
{
HttpServletRequest request;
HttpServletResponse response;
if (!(req instanceof HttpServletRequest &&
res instanceof HttpServletResponse)) {
throw new ServletException("non-HTTP request or response");
}
request = (HttpServletRequest) req;
response = (HttpServletResponse) res;
service(request, response);
}
}
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
String method = req.getMethod();
if (method.equals(METHOD_GET)) {
long lastModified = getLastModified(req);
if (lastModified == -1) {
// servlet doesn‘t support if-modified-since, no reason
// to go through further expensive logic
doGet(req, resp);
} else {
long ifModifiedSince = req.getDateHeader(HEADER_IFMODSINCE);
if (ifModifiedSince < lastModified) {
// If the servlet mod time is later, call doGet()
// Round down to the nearest second for a proper compare
// A ifModifiedSince of -1 will always be less
maybeSetLastModified(resp, lastModified);
doGet(req, resp);
} else {
resp.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
}
}
} else if (method.equals(METHOD_HEAD)) {
long lastModified = getLastModified(req);
maybeSetLastModified(resp, lastModified);
doHead(req, resp);
} else if (method.equals(METHOD_POST)) {
doPost(req, resp);
} else if (method.equals(METHOD_PUT)) {
doPut(req, resp);
} else if (method.equals(METHOD_DELETE)) {
doDelete(req, resp);
} else if (method.equals(METHOD_OPTIONS)) {
doOptions(req,resp);
} else if (method.equals(METHOD_TRACE)) {
doTrace(req,resp);
} else {
//
// Note that this means NO servlet supports whatever
// method was requested, anywhere on this server.
//
String errMsg = lStrings.getString("http.method_not_implemented");
Object[] errArgs = new Object[1];
errArgs[0] = method;
errMsg = MessageFormat.format(errMsg, errArgs);
resp.sendError(HttpServletResponse.SC_NOT_IMPLEMENTED, errMsg);
}
}可以看到HttpServlet service 进行了重载，根据不同的请求类型然后调用不同处理方法，这里以get请求为例，当请求方法为get 请求时在重载service 方法中调用doGet 方法进行处理，这里需要特别注意的是:HttpServlet 存在doGet方法实现，然而在继承的子类中也存在doGet方法实现，到底调用哪个方法？很明显调用子类的doGet方法(面向对象多态思想!!!),从继承UML关系图上看，最外层子类实现doGet方法的为FrameworkServlet
@Override
protected final void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
proce***equest(request, response);
}
protected final void proce***equest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 系统计时开始时间
long startTime = System.currentTimeMillis();
Throwable failureCause = null;
// 国际化
LocaleContext previousLocaleContext = LocaleContextHolder.getLocaleContext();
LocaleContext localeContext = buildLocaleContext(request);
//构建ServletRequestAttributes对象
RequestAttributes previousAttributes = RequestContextHolder.getRequestAttributes();
ServletRequestAttributes requestAttributes = buildRequestAttributes(request, response, previousAttributes);
//异步管理
WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
asyncManager.registerCallableInterceptor(FrameworkServlet.class.getName(), new RequestBindingInterceptor());
//初始化ContextHolders
initContextHolders(request, localeContext, requestAttributes);
try {
doService(request, response);
}
catch (ServletException | IOException ex) {
failureCause = ex;
throw ex;
}
catch (Throwable ex) {
failureCause = ex;
throw new NestedServletException("Request processing failed", ex);
}
finally {
//恢复原来的LocaleContext和ServiceRequestAttributes到LocaleContextHolder和RequestContextHolder，避免影响Servlet以外的处理，如Filter
resetContextHolders(request, previousLocaleContext, previousAttributes);
if (requestAttributes != null) {
requestAttributes.requestCompleted();
}
logResult(request, response, failureCause, asyncManager);
//发布ServletRequestHandlerEvent消息，这个请求是否执行成功都会发布消息的
publishRequestHandledEvent(request, response, startTime, failureCause);
}
}
// initContextHolders(request, localeContext, requestAttributes);
private void initContextHolders(HttpServletRequest request,
@Nullable LocaleContext localeContext, @Nullable RequestAttributes requestAttributes) {
if (localeContext != null) {
LocaleContextHolder.setLocaleContext(localeContext, this.threadContextInheritable);
}
if (requestAttributes != null) {
RequestContextHolder.setRequestAttributes(requestAttributes, this.threadContextInheritable);
}
}? 该方法大概做了这几件事：国际化的设置，创建ServletRequestAttributes对象，初始化上下文holders(即将Request对象放入到线程上下文中，如后续想要在方法中获取request,response对象此时可以通过调用LocaleContextHolder对应方法即可)，然后调用doService方法。对于doService方法，FrameworkServlet 类并未提供实现，该方法由DispatcherServlet子类实现
DispatcherServlet里面执行处理的入口方法是doService，由于这个类继承于FrameworkServlet类，重写了doService()方法
@Override
protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception {
logRequest(request);
// Keep a snapshot of the request attributes in case of an include,
// to be able to restore the original attributes after the include.
Map<String, Object> attributesSnapshot = null;
if (WebUtils.isIncludeRequest(request)) {
attributesSnapshot = new HashMap<>();
Enumeration<?> attrNames = request.getAttributeNames();
while (attrNames.hasMoreElements()) {
String attrName = (String) attrNames.nextElement();
if (this.cleanupAfterInclude || attrName.startsWith(DEFAULT_STRATEGIES_PREFIX)) {
attributesSnapshot.put(attrName, request.getAttribute(attrName));
}
}
}
//Spring上下文
request.setAttribute(WEB_APPLICATION_CONTEXT_ATTRIBUTE, getWebApplicationContext());
//国际化解析器
request.setAttribute(LOCALE_RESOLVER_ATTRIBUTE, this.localeResolver);
//主题解析器
request.setAttribute(THEME_RESOLVER_ATTRIBUTE, this.themeResolver);
//主题
request.setAttribute(THEME_SOURCE_ATTRIBUTE, getThemeSource());
//重定向的数据
if (this.flashMapManager != null) {
FlashMap inputFlashMap = this.flashMapManager.retrieveAndUpdate(request, response);
if (inputFlashMap != null) {
request.setAttribute(INPUT_FLASH_MAP_ATTRIBUTE, Collections.unmodifiableMap(inputFlashMap));
}
request.setAttribute(OUTPUT_FLASH_MAP_ATTRIBUTE, new FlashMap());
request.setAttribute(FLASH_MAP_MANAGER_ATTRIBUTE, this.flashMapManager);
}
try {
//request设置完相关的属性做真正的请求处理
doDispatch(request, response);
}
finally {
if (!WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) {
// Restore the original attribute snapshot, in case of an include.
if (attributesSnapshot != null) {
restoreAttributesAfterInclude(request, attributesSnapshot);
}
}
}
}? 整个方法看下来处理的操作有:处理include标签的请求，将上下文放到request的属性中，将国际化解析器放到request的属性中，将主题解析器放到request属性中，将主题放到request的属性中，处理重定向的请求数据最后调用doDispatch这个核心的方法对请求进行处理。
DispatcherServlet#doDispatch
该方法是在doService方法中调用的，从底层设计了整个请求的处理流程:
protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
HttpServletRequest processedRequest = request;
HandlerExecutionChain mappedHandler = null;
boolean multipartRequestParsed = false;
WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
try {
ModelAndView mv = null;
Exception dispatchException = null;
try {
// 校验是否为上传请求 是上传请求执行解析 否则返回request
processedRequest = checkMultipart(request);
multipartRequestParsed = (processedRequest != request);
// 根据访问的Handler 返回指定对应的HandlerExecutionChain对象 这里从HandlerMapping 集合中查找 HandlerExecutionChain 对象包含Handler与拦截器HandlerInterceptor列表
mappedHandler = getHandler(processedRequest);
if (mappedHandler == null) {
noHandlerFound(processedRequest, response);
return;
}
// 根据得到的Handler 获取对应的HandlerAdaptor对象
HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());
// 处理GET、HEAD请求的Last-Modified
String method = request.getMethod();
boolean isGet = "GET".equals(method);
if (isGet || "HEAD".equals(method)) {
long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
//当数据没有更改时，就直接返回上次的数据，提高效率
if (new ServletWebRequest(request, response).checkNotModified(lastModified) && isGet) {
return;
}
}
//执行Interceptor的preHandle
if (!mappedHandler.applyPreHandle(processedRequest, response)) {
return;
}
// 执行Handler 返回ModelAndView
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
//如果需要异步处理，直接返回
if (asyncManager.isConcurrentHandlingStarted()) {
return;
}
//当view为空时，根据request设置默认view，如Handler返回值为void
applyDefaultViewName(processedRequest, mv);
//执行相应Interceptor的postHandle
mappedHandler.applyPostHandle(processedRequest, response, mv);
}
catch (Exception ex) {
dispatchException = ex;
}
catch (Throwable err) {
// As of 4.3, we‘re processing Errors thrown from handler methods as well,
// making them available for @ExceptionHandler methods and other scenarios.
dispatchException = new NestedServletException("Handler dispatch failed", err);
}
//处理返回结果，包括处理异常、渲染页面，发出完成通知触发Interceptor的afterCompletion
processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);
}
catch (Exception ex) {
triggerAfterCompletion(processedRequest, response, mappedHandler, ex);
}
catch (Throwable err) {
triggerAfterCompletion(processedRequest, response, mappedHandler,
new NestedServletException("Handler processing failed", err));
}
finally {
if (asyncManager.isConcurrentHandlingStarted()) {
// Instead of postHandle and afterCompletion
if (mappedHandler != null) {
mappedHandler.applyAfterConcurrentHandlingStarted(processedRequest, response);
}
}
else {
// Clean up any resources used by a multipart request.
if (multipartRequestParsed) {
cleanupMultipart(processedRequest);
}
}
}
} 1. doDispatcher首先检查是不是上传请求，如果是则将request转换为MultipartHttpServletRequest，并将multipartRequestParsed标志设置为true processDispatchResult方法主要用来处理前面返回的结果，其中包括处理异常、渲染页面、触发Interceptor的afterCompletion方法三部分内容，处理的异常是在处理请求doDispatch方的过程中产生。private void processDispatchResult(HttpServletRequest request, HttpServletResponse response,
@Nullable HandlerExecutionChain mappedHandler, @Nullable ModelAndView mv,
@Nullable Exception exception) throws Exception {
boolean errorView = false;
// 如果请求过程中有异常抛出则处理异常
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);
}
}
//执行页面渲染操作
if (mv != null && !mv.wasCleared()) {
render(mv, request, response);
if (errorView) {
WebUtils.clearErrorRequestAttributes(request);
}
}
else {
if (logger.isTraceEnabled()) {
logger.trace("No view rendering, null ModelAndView returned.");
}
}
if (WebAsyncUtils.getAsyncManager(request).isConcurrentHandlingStarted()) {
// Concurrent handling started during a forward
return;
}
// Handler请求处理完，触发Interceptor的afterCompletion
if (mappedHandler != null) {
// Exception (if any) is already handled..
mappedHandler.triggerAfterCompletion(request, response, null);
}
}render 视图渲染
protected void render(ModelAndView mv, HttpServletRequest request, HttpServletResponse response) throws Exception {
// Determine locale for request and apply it to the response.
Locale locale =
(this.localeResolver != null ? this.localeResolver.resolveLocale(request) : request.getLocale());
response.setLocale(locale);
View view;
String viewName = mv.getViewName();
if (viewName != null) {
// We need to resolve the view name.
view = resolveViewName(viewName, mv.getModelInternal(), locale, request);
if (view == null) {
throw new ServletException("Could not resolve view with name ‘" + mv.getViewName() +
"‘ in servlet with name ‘" + getServletName() + "‘");
}
}
else {
// No need to lookup: the ModelAndView object contains the actual View object.
view = mv.getView();
if (view == null) {
throw new ServletException("ModelAndView [" + mv + "] neither contains a view name nor a " +
"View object in servlet with name ‘" + getServletName() + "‘");
}
}
if (logger.isTraceEnabled()) {
logger.trace("Rendering view [" + view + "] ");
}
try {
if (mv.getStatus() != null) {
response.setStatus(mv.getStatus().value());
}
// 渲染页面处理
view.render(mv.getModelInternal(), request, response);
}
catch (Exception ex) {
if (logger.isDebugEnabled()) {
logger.debug("Error rendering view [" + view + "]", ex);
}
throw ex;
}
}客户端请求被 DispatcherServlet（前端控制器）接收。
->根据 HandlerMapping 映射到 Handler。
->生成 Handler 和 HandlerInterceptor（如果有则生成）。
->Handler 和 HandlerInterceptor 以 HandlerExecutionChain 的形式一并返回给 DispatcherServlet。
->DispatcherServlet 通过 HandlerAdapter 调用 Handler 的方法做业务逻辑处理。
->返回一个 ModelAndView 对象给 DispatcherServlet。
->DispatcherServlet 将获取的 ModelAndView 对象传给 ViewResolver 视图解析器，将逻辑视图解析成物理视图 View。
->ViewResolver 返回一个 View 给 DispatcherServlet。
->DispatcherServlet 根据 View 进行视图渲染（将模型数据填充到视图中）。
->DispatcherServlet 将渲染后的视图响应给客户端。HTTP 请求是通过注解找到对应的 Controller 对象…；
Controller 的 Method 也是通过注解与 HTTP 请求映射的；
使用map 当做 ioC 容器，完成储存所有参数与业务的class;业务逻辑
初始化工作完成，接下来处理 HTTP 请求，业务流程如下：
DispatcherServlet 接收请求，通过映射从 IoC 容器中获取对应的 Controller 对象；
根据映射获取 Controller 对象对应的 Method；
调用 Method，获取返回值；
将返回值传给视图解析器，返回物理视图；
完成页面跳转。@MyController
@MyRequestMapping
/**
* 自定义 @RequestMapping 注解
*/
@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyRequestMapping {
String value() default "";
}
/**
* @auther SyntacticSugar
* @data 2018/11/13 0013下午 9:15
*/
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyController {
String value() default "";
}
/**
* @auther SyntacticSugar
* @data 2018/11/13 0013下午 9:20
* <p>
* 创建控制器
*/
public class MyDispatcherServlet extends HttpServlet {
//创建ioC 创建 handler存放容器
private HashMap<String, Object> ioC = new HashMap<>();
private HashMap<String, Method> handlerMapping = new HashMap<>();
//自定义视图解析
private MyViewResolver myViewResolver;
@Override
public void init(ServletConfig config) throws ServletException {
// 把controller放到ioC中
scanController(config);
//初始化handler 映射
initHandlerMapping();
//加载视图解析器
loadViewResolver(config);
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String handlerUri = req.getRequestURI().split("/")[2];
String methodUri = req.getRequestURI().split("/")[3];
//
Object o = ioC.get(handlerUri);
Method method = handlerMapping.get(methodUri);
// 使用反射机制,调用执行 业务
try {
String value = (String) method.invoke(o);
// 将逻辑视图 转化为 物理视图，交给 view渲染返回前端
String result = myViewResolver.jspMapping(value);
req.getRequestDispatcher(result).forward(req,resp );
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* saxReader 解析springmvc.xml
* @param config
*/
private void scanController(ServletConfig config) {
SAXReader saxReader = new SAXReader();
try {
String path = config.getServletContext().getRealPath("") + "\\WEB-INF\\classes\\" +
config.getInitParameter("contextConfigLocation");
Document document = saxReader.read(path);
// 获取根元素
Element rootElement = document.getRootElement();
Iterator iterator = rootElement.elementIterator();
// 遍历 nodes 、sax解析每一行xml
while (iterator.hasNext()) {
Element next = (Element) iterator.next();
// 把每一个元素的name和 component-scan 比较，获取base-package值
if (next.getName().equals("component-scan")) {
String packageName = next.attributeValue("base-package");
// 获取包下 每个子包
List<String> classNames = getClassNames(packageName);
for (String className : classNames) {
/**
通过反射获取clazz ，判断class上是否存在MyController注解
* 若存在 、获取MyRequestMapping 的 value , 并将其 装入 自定义的ioC
*/
Class<?> clazz = Class.forName(className);
if (clazz.isAnnotationPresent(MyController.class)) {
MyRequestMapping annotation = clazz.getAnnotation(MyRequestMapping.class);
String value = annotation.value().substring(1);
// 放入ioC
ioC.put(value,clazz.newInstance() );
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取 <context:component-scan base-package="com.baidu"/> 所有class 全路径名
* @param packageName
* @return
*/
private List<String> getClassNames(String packageName) {
List<String> classNameList = new ArrayList<String>();
String path = packageName.replace(".", "/");
//已知存在包路径，获取每一级路径下的file、 获取类加载器,
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
URL url = classLoader.getResource(path);
//非空判断
if (url != null) {
File[] files = new File(url.getPath()).listFiles();
//遍历取值
for (File childFile : files) {
String className = packageName + "." + childFile.getName().replace(".class", "");
classNameList.add(className);
}
}
// return
return classNameList;
}
/**
* 初始化 handler
*/
private void initHandlerMapping() {
//从ioC中取出 MyController注解的 class
for (String s : ioC.keySet()) {
Class<?> clazz = ioC.get(s).getClass();
Method[] methods = clazz.getMethods();
//遍历
for (Method method : methods) {
// 判断哪一个被 @MyRequestMapping 注解标识
if (method.isAnnotationPresent(MyRequestMapping.class)) {
MyRequestMapping annotation = method.getAnnotation(MyRequestMapping.class);
String value = annotation.value().substring(1);
// 存入 handler
handlerMapping.put(value,method );
}
}
}
}
/**
* 加载自定义视图 saxReader 解析springmvc.xml
* @param config
*/
private void loadViewResolver(ServletConfig config) {
SAXReader reader = new SAXReader();
try {
String path = config.getServletContext().getRealPath("")+"\\WEB-INF\\classes\\"+config.getInitParameter("contextConfigLocation");
Document document = reader.read(path);
Element root = document.getRootElement();
Iterator iter = root.elementIterator();
//遍历
while(iter.hasNext()){
Element ele = (Element) iter.next();
if(ele.getName().equals("bean")){
String className = ele.attributeValue("class");
Class clazz = Class.forName(className);
Object obj = clazz.newInstance();
//获取 setter 方法
Method prefixMethod = clazz.getMethod("setPrefix", String.class);
Method suffixMethod = clazz.getMethod("setSuffix", String.class);
Iterator beanIter = ele.elementIterator();
//获取 property 值
Map<String,String> propertyMap = new HashMap<String,String>();
while(beanIter.hasNext()){
Element beanEle = (Element) beanIter.next();
String name = beanEle.attributeValue("name");
String value = beanEle.attributeValue("value");
propertyMap.put(name, value);
}
for(String str:propertyMap.keySet()){
//反射机制调用 setter 方法，完成赋值
if(str.equals("prefix")){
prefixMethod.invoke(obj, propertyMap.get(str));
}
if(str.equals("suffix")){
suffixMethod.invoke(obj, propertyMap.get(str));
}
}
myViewResolver = (MyViewResolver) obj;
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* @auther SyntacticSugar
* @data 2018/11/13 0013下午 9:31
*
* 自定义视图解析器 MyViewResolver
*/
public class MyViewResolver {
private String prefix;
private String suffix;
// 目标资源路径
public String jspMapping(String value){
return this.prefix+value+this.suffix;
}
//setter getter
......
}
/**
* @auther SyntacticSugar
* @data 2018/11/13 0013下午 10:47
*/
@MyController
@MyRequestMapping("/testController")
public class TestController {
@MyRequestMapping("/test")
public String test(){
System.out.println("执行test相关业务");
return "index";
}
}
<?xml version="1.0" encoding="UTF-8"?>
<beans>
<component-scan base-package="com.baidu"/>
<!-- 配置视图解析器 ,拦截器 -->
<bean class="com.baidu.view.MyViewResolver">
<property name="prefix" value="/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>如果需要更多资料：1080355292（进群暗号：99）
标签：determine gets win 处理流程 后台 查找 exp request对象 isa
原文地址：https://blog.51cto.com/14865341/2509308
