SpringMVC工作原理详解

<listener>
            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
        </listener>        
        <servlet>
  <servlet-name>springmvc</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
                <!-- 如果不设置init-param标签，则必须在/WEB-INF/下创建xxx-servlet.xml文件，其中xxx是servlet-name中配置的名称。  -->
                <init-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:spring/springmvc-servlet.xml</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
  <servlet-name>springmvc</servlet-name>
  <url-pattern>/</url-pattern>
  </servlet-mapping>

package org.springframework.web.servlet;
@SuppressWarnings("serial")
public class DispatcherServlet extends FrameworkServlet {
  public static final String MULTIPART_RESOLVER_BEAN_NAME = "multipartResolver";
  public static final String LOCALE_RESOLVER_BEAN_NAME = "localeResolver";
  public static final String THEME_RESOLVER_BEAN_NAME = "themeResolver";
  public static final String HANDLER_MAPPING_BEAN_NAME = "handlerMapping";
  public static final String HANDLER_ADAPTER_BEAN_NAME = "handlerAdapter";
  public static final String HANDLER_EXCEPTION_RESOLVER_BEAN_NAME = "handlerExceptionResolver";
  public static final String REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME = "viewNameTranslator";
  public static final String VIEW_RESOLVER_BEAN_NAME = "viewResolver";
  public static final String FLASH_MAP_MANAGER_BEAN_NAME = "flashMapManager";
  public static final String WEB_APPLICATION_CONTEXT_ATTRIBUTE = DispatcherServlet.class.getName() + ".CONTEXT";
  public static final String LOCALE_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".LOCALE_RESOLVER";
  public static final String THEME_RESOLVER_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_RESOLVER";
  public static final String THEME_SOURCE_ATTRIBUTE = DispatcherServlet.class.getName() + ".THEME_SOURCE";
  public static final String INPUT_FLASH_MAP_ATTRIBUTE = DispatcherServlet.class.getName() + ".INPUT_FLASH_MAP";
  public static final String OUTPUT_FLASH_MAP_ATTRIBUTE = DispatcherServlet.class.getName() + ".OUTPUT_FLASH_MAP";
  public static final String FLASH_MAP_MANAGER_ATTRIBUTE = DispatcherServlet.class.getName() + ".FLASH_MAP_MANAGER";
  public static final String EXCEPTION_ATTRIBUTE = DispatcherServlet.class.getName() + ".EXCEPTION";
  public static final String PAGE_NOT_FOUND_LOG_CATEGORY = "org.springframework.web.servlet.PageNotFound";
  private static final String DEFAULT_STRATEGIES_PATH = "DispatcherServlet.properties";
  protected static final Log pageNotFoundLogger = LogFactory.getLog(PAGE_NOT_FOUND_LOG_CATEGORY);
  private static final Properties defaultStrategies;
  static {
  try {
    ClassPathResource resource = new ClassPathResource(DEFAULT_STRATEGIES_PATH, DispatcherServlet.class);
    defaultStrategies = PropertiesLoaderUtils.loadProperties(resource);
  }
  catch (IOException ex) {
    throw new IllegalStateException("Could not load 'DispatcherServlet.properties': " + ex.getMessage());
  }
  }
  /** Detect all HandlerMappings or just expect "handlerMapping" bean? */
  private boolean detectAllHandlerMappings = true;
  /** Detect all HandlerAdapters or just expect "handlerAdapter" bean? */
  private boolean detectAllHandlerAdapters = true;
  /** Detect all HandlerExceptionResolvers or just expect "handlerExceptionResolver" bean? */
  private boolean detectAllHandlerExceptionResolvers = true;
  /** Detect all ViewResolvers or just expect "viewResolver" bean? */
  private boolean detectAllViewResolvers = true;
  /** Throw a NoHandlerFoundException if no Handler was found to process this request? **/
  private boolean throwExceptionIfNoHandlerFound = false;
  /** Perform cleanup of request attributes after include request? */
  private boolean cleanupAfterInclude = true;
  /** MultipartResolver used by this servlet */
  private MultipartResolver multipartResolver;
  /** LocaleResolver used by this servlet */
  private LocaleResolver localeResolver;
  /** ThemeResolver used by this servlet */
  private ThemeResolver themeResolver;
  /** List of HandlerMappings used by this servlet */
  private List<HandlerMapping> handlerMappings;
  /** List of HandlerAdapters used by this servlet */
  private List<HandlerAdapter> handlerAdapters;
  /** List of HandlerExceptionResolvers used by this servlet */
  private List<HandlerExceptionResolver> handlerExceptionResolvers;
  /** RequestToViewNameTranslator used by this servlet */
  private RequestToViewNameTranslator viewNameTranslator;
  private FlashMapManager flashMapManager;
  /** List of ViewResolvers used by this servlet */
  private List<ViewResolver> viewResolvers;
  public DispatcherServlet() {
  super();
  }
  public DispatcherServlet(WebApplicationContext webApplicationContext) {
  super(webApplicationContext);
  }
  @Override
  protected void onRefresh(ApplicationContext context) {
  initStrategies(context);
  }
  protected void initStrategies(ApplicationContext context) {
  initMultipartResolver(context);
  initLocaleResolver(context);
  initThemeResolver(context);
  initHandlerMappings(context);
  initHandlerAdapters(context);
  initHandlerExceptionResolvers(context);
  initRequestToViewNameTranslator(context);
  initViewResolvers(context);
  initFlashMapManager(context);
  }
}