1.дSpringעʽʵֵĲ  
2.дעʽ Spring  MVC ʵֵĲ 
3.Spring MVC Ŀлȡ 
4.Spring MVC ҳ洫 
5.Spring ʵض  
------------------------------------------------------------
1.Spring еض
  1.1  ַʱ 
   "redirect:·"     
    toLogin.do     /toLogin.do 
    /  ĿԼĿǰĲ 
  1.2 з  ModelAndView
     RedirectView  rv =  new  RedirectView("·");
     toLogin.do     /toLogin.do 
     /   ĿǰĲ Ŀ
2. 
  2.1  ֮ǰķʽȻ 
      get   post Ĵʽ
  2.2  ʹSpring ṩı  
            ֻpost ʽ
3. 
  3.1 
      ʵ ־¼   Ȩ޼      ܼ   
  3.2 ʵ?
    a.Զ ʵ HandlerInterceptor ӿ 
            ڶӦķбдҵ߼
      preHandle  ֮ǰ
      postHandle  ֮  ͼ֮ǰ
      afterCompletion  ͼ֮ Ӧ֮ǰ
    b.Spring ļ  
      <mvc:interceptors>
          <mvc:interceptor>
              <mvc:mapping path="/user/*" />
              <mvc:exclude-mapping path="/user/*" />
              <bean  class="" />
          </mvc:interceptor>
      </mvc:interceptors>
   3.3 д ֱ /user/userInfo.do   /user/toLogin.do  /user/login.do  
      Ҫֻ/user/userInfo.do  /user/toLogin.do  /user/login.do 
      עص ûǷ¼(sessionеusernameǲnull)  ¼ 
      ʾû¼ 
   
   3.4 Զִ˳ 
   preHandle  ˳һ   ˳෴
   
   4.Spring е쳣   
     4.1  ʹSpring ṩ SimpleMappingExceptionResolver  ȫ쳣 
      <bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
         <property name="exceptionMappings">
              <props>
                    <prop key="java.lang.Exception">error1</prop>
                    <prop key="java.lang.RuntimeException">error2</prop>
              </props>
         </property>
    </bean>
     4.2  Զ쳣   ȫ쳣
           ʵ   HandlerExceptionResolver
     public ModelAndView resolveException(HttpServletRequest arg0,
		HttpServletResponse arg1, Object arg2,
		Exception e) {
		ModelAndView mav = new ModelAndView();
		if( e  instanceof RuntimeException){
			 mav.setViewName("error2");
		}else if(e instanceof Exception){
			 mav.setViewName("error1");
		}
		return  mav;
	}       
     4.3  ֲ쳣 (ĳһĿ )
      @ExceptionHandler
      public  String execute(Exception e){
	      return  "error3";
      }
     
     
     
     
   
   
   
   
   
    
   
   
     
   
   
   
  
  
  
            
  
  
  
  
  
              
       
       
       
       
       
       