最近把spring的使用整理下，版本4.1.1.RELEASE
SpringMVC是一个基于DispatcherServlet的MVC框架，每一个请求先访问的都是DispatcherServlet，DispatcherServlet负责转发每一个Request请求给相应的Handler，Handler处理以后再返回相应的视图(View)和模型(Model)，返回的视图和模型都可以不指定，即可以只返回Model或只返回View或都不返回。
<!--spring-mvc入口-->
<servlet>
<servlet-name>appServlet</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>
<load-on-startup>0</load-on-startup>
</servlet>
servlet-context.xml内容如下：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!--处理静态资源-->
<mvc:resources mapping="/resources/**" location="/resources/"/> <!--注解类所在jar包-->
<context:component-scan base-package="springtry.web.controller">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Service"/>
</context:component-scan> <!--启动注解处理(@Controller等)-->
<mvc:annotation-driven
content-negotiation-manager="contentNegotiationManager"
conversion-service="conversionService"/>
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
<!-- 处理请求和注解POJO的映射 -->
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<property name="messageConverters">
<list>
<ref bean="mappingJacksonHttpMessageConverter" /><!--json转换器-->
</list>
</property>
</bean>
<bean id="mappingJacksonHttpMessageConverter"
class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="supportedMediaTypes"><!--request/response的Content-Typ-->
<list>
<value>text/html;charset=UTF-8</value><!-- 避免IE执行AJAX时,返回JSON出现下载文件 -->
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean> <bean id="conversionService"
class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
<property name="converters">
<set>
<!-- <bean class="***" /> -->
</set>
</property>
</bean> <!--视图协商管理器-->
<bean id="contentNegotiationManager"
class="org.springframework.web.accept.ContentNegotiationManager">
<constructor-arg>
<bean class="org.springframework.web.accept.PathExtensionContentNegotiationStrategy">
<constructor-arg>
<map>
<entry key="json" value="application/json;charset=utf-8"/>
<entry key="xml" value="application/xml;charset=utf-8"/>
</map>
</constructor-arg>
</bean>
</constructor-arg>
</bean> <bean id="velocityConfigurer"
class="org.springframework.web.servlet.view.velocity.VelocityConfigurer">
<property name="resourceLoaderPath" value="/WEB-INF/vm/"/>
<property name="velocityProperties">
<props>
<prop key="directive.foreach.counter.name">loopCounter</prop>
<prop key="directive.foreach.counter.initial.value">0</prop>
<prop key="input.encoding">UTF-8</prop>
<prop key="output.encoding">UTF-8</prop>
<prop key="directive.foreach.counter.name">velocityCount</prop>
<prop key="directive.foreach.counter.initial.value">1</prop>
<prop key="velocimacro.library.autoreload">true</prop>
</props>
</property>
</bean> <!--支持在Spring MVC下输出不同的格式-->
<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<property name="order" value="1"/>
<property name="contentNegotiationManager" ref="contentNegotiationManager"/>
<property name="viewResolvers">
<list>
<bean class="org.springframework.web.servlet.view.BeanNameViewResolver"/>
<bean class="org.springframework.web.servlet.view.velocity.VelocityViewResolver">
<property name="order" value="0"/>
<property name="cache" value="true"/>
<property name="prefix" value=""/>
<property name="suffix" value=".vm"/>
<property name="toolboxConfigLocation" value="/WEB-INF/toolbox.xml"/>
<property name="contentType" value="text/html;charset=UTF-8"/>
<property name="viewClass" value="springtry.web.util.VelocityToolbox2View"></property>
<!--<property name="attributesMap">
<map>
<entry key="sec">
<ref bean="velocitySecurityUtil"/>
</entry>
<entry key="req">
<ref bean="requestUtil"/>
</entry>
</map>
</property>-->
</bean>
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/views/"/>
<property name="suffix" value=".jsp"/>
</bean>
</list>
</property>
<property name="defaultViews">
<list>
<bean id="jsonView"
class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"/>
</list>
</property>
</bean> <bean id="exceptionResolver"
class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
<property name="defaultErrorView" value="errors/error"/>
<property name="exceptionMappings">
<props>
<prop key="java.lang.Throwable">errors/error</prop>
</props>
</property>
</bean> </beans>
详解：
1.<mvc:annotation-driven />标签,使用了比较重要的两个bean
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
解析类是org.springframework.web.servlet.config.AnnotationDrivenBeanDefinitionParser,通过使用
RootBeanDefinition handlerMappingDef = new RootBeanDefinition(RequestMappingHandlerMapping.class);
处理@RequestMapping,并将其注册到请求映射表中
通过使用
RootBeanDefinition handlerAdapterDef = new RootBeanDefinition(RequestMappingHandlerAdapter.class);
...
this.addResponseBodyAdvice(handlerAdapterDef);
处理@Controller,确定调用哪个controller的哪个方法来处理当前请求
ps:网上说这个标签等同于单独定义这两个bean，我有异议，推荐同时使用，可以个性化定制RequestMappingHandlerMapping和RequestMappingHandlerAdapter
2.conversion-service="conversionService",上面的配置中使用了这项，什么意思呢？
提交到后台的数据通常都是字符串类型的，需要进行类型转换，这就是conversionService的作用了，发现一个问题，这个不是和RequestMappingHandlerAdapter定义的messageConverters冲突了么？没关系，因为messageConverters只针对requestBody(@RequestBody)
后面再详细介绍conversionService的各种类型转换
3.<bean id="contentNegotiationManager" class="org.springframework.web.accept.ContentNegotiationManager"/>
以什么MediaTypes相应请求
4.<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
协商视图解析器