Spring之MVC模块

Spring MVC的Controller用于处理用户的请求。Controller相当于Struts 1里的Action，他们的实现机制、运行原理都类似

Controller是个接口，一般直接继承AbstrcatController，并实现handleRequestInternal方法。handleRequestInternal方法相当于Struts 1的execute方法

 

import org.springframework.web.servlet.ModelAndView;import org.springframework.web.servlet.mvc.AbstractController; public class CatController extends AbstractController{      private ICatService catService;      //setter、getter略       protected ModelAndView handleRequestInternal(HttpServletRequestrequest,HttpServletResponse response) throws Exception{             String action =request.getParameter("action");             if("list".equals(action)){                    return this.list(request,response);             }      }       protected ModelAndView list(HttpServletRequestrequest,HttpServletResponse response) throws Exception{             List<Cat> catList =catService.listCat();             request.setAttribute("catList", catList);             return new ModelAndView("cat/listCat");      }     }

Spring MVC没有内置数据的封装，开发者可以自己封装数据转换代码

Spring MVC独特的地方在于view层的处理上。handleRequestInternal返回ModelAndView对象，可以看做是对JSP对象的封装。ModelAndIView直接接受JSP页面的路径。例如参数＂cat/listCat＂，只是JSP路径的一部分，实际完整的路径是＂WEB-INF/jsp/cat/catList.jsp＂，路径前后的部分是配置在配置文件中的

除了制定JSP路径，ModelAndView还可以直接传递Model对象到View层，而不用事先放到request中，例如new ModelAndView(＂cat/listCat＂,＂cat＂,cat)，如果传递多个参数，可以使用Map，如

Map map = newHashMap();map.put("cat",cat);map.put("catList",catList);return new ModelAndView("cat/listCat",map);

 

一般使用一个独立的xml文件如spring-action.xml专门配置web相关的组件

<?xml version= "1.0" encoding="UTF-8"?><!DCTYPEbeans PUBLIC "-//SPRING//DTD BEAN//EN"  "http://www.springframework.org/dtd/spring-beans.dtd"><beans>      <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">             <property name="prefix">                    <value>/WEB-INF/jsp/</value><!--  JSP前缀-->             </property>             <property name="suffix">                    <value>.jsp</value>                 <!--  JSP后缀-->             </property>       <!-- 配置URL Mapping-->      <bean id="urlHandlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandleMapping">             <property name="mappings">                    <props><!—Controller的URL会被配置成"cat.mvc"-->                           <prop key="cat.mvc">catController</prop>                    <props>             </property>      </bean>      <bean id="catController" class="com.clf.spring.CatController">             <property name="catService" ref="catService"></property>      </bean></beans> web.xml配置<context-param><!--  Spring配置文件的位置-->      <param-name>contextConfigLocation</param-name>      <param-value>             /WEB-INF/classes/applicationContext.xml,             /WEB-INF/classes/spring-action.xml         </param-value></context-param> <listener><!--  使用Listener加载Spring配置文件-->      <listener-class>             org.springframework.web.context.ContextLoaderListener      </listener-class></listener> <servlet><!--  spring分发器-->      <servlet-name>spring</servlet-name>      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>      <init-param>             <param-name>contextConfigLocation</param-name>             <param-value>/WEB-INF/classes/spring-action.xml</param-value>      </init-param>      <load-on-startup>1</load-on-startup><!--  启动时加载--></servlet> <servlet-mapping>      <servlet-name> spring</servlet-name>      <url>*.mvc</url></servlet-mapping>

 

如果一个Controller要处理多个业务逻辑，可以使用MultiActionController，相当于Struts 1中的DispatchAction，能根据某个参数将不同的请求分发到不同的方法上

import org.springframework.web.servlet.mvc.multiaction.MultiActionController; public class CatController extends AbstractController{      private ICatService catService;      //setter、getter略       protected ModelAndView add(HttpServletRequestrequest,HttpServletResponse response) throws Exception{             ……             return new ModelAndView(＂cat/addCat＂);      }       protected ModelAndView list(HttpServletRequestrequest,HttpServletResponse response) throws Exception{             List<Cat> catList =catService.listCat();             request.setAttribute(＂catList＂, catList);             return new ModelAndView(＂cat/listCat＂);      }     }

 

配置到spring-action.xml

<bean id="paraMethodResolver" class="org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver">      <property name="paramName">             <value>action</value><!--  配置分发参数-->      </property>      <property name="defaultMethodName">             <value>list</value><!--  配置默认的执行方法-->      </property></bean> <bean id="urlHandlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandleMapping">             <property name="mappings">                    <props>                           <prop key="cat.mvc">catController</prop><!--  访问"cat.mvc"则交给catController处理-->                           <prop key="catMulti.mvc">catMultiController</prop><!--  访问"catMulti.mvc"则交给catMultiController处理-->                    <props>             </property>      </bean>       <bean id="catController" class="com.clf.spring.CatMultiController">             <property name="catService" ref="catService"></property>      </bean>       <bean id="catMultiController" class="com.clf.spring.CatController">             <property name="catService" ref="catService"></property>      </bean>