springmvc配置的全解析,致敬即将远去的mvc

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springmvc最为人称道的就是过多的xml配置,繁琐且复杂,本文将按照加载顺序逐一介绍配置,附上文件结构。

1.加载web.xml

启动时,第一步加载web.xml,初始化上线文与核心控制器DispatcherServlet 。

<?xml version="1.0" encoding="UTF-8"?>    
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    
    xmlns="http://java.sun.com/xml/ns/javaee"    
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"    
    version="3.0">    
    <display-name>Archetype Created Web Application</display-name>    
        
    <welcome-file-list>    
        <welcome-file>/index.jsp</welcome-file>    
    </welcome-file-list>    
        
    <!-- 加载applicationContext.xml配置文件 -->    
    <context-param>    
         <param-name>contextConfigLocation</param-name>    
        <param-value>classpath:applicationContext.xml</param-value>    
    </context-param>    
    
    <!-- 创建WebApplicationContext(上下文) -->
    <listener>    
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>    
    </listener>    
        
    <!-- 编码过滤器 -->    
    <filter>    
        <filter-name>encodingFilter</filter-name>    
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>    
        <async-supported>true</async-supported>    
        <init-param>    
            <param-name>encoding</param-name>    
            <param-value>UTF-8</param-value>    
        </init-param>    
    </filter>    
    <filter-mapping>    
        <filter-name>encodingFilter</filter-name>    
        <url-pattern>/*</url-pattern>    
    </filter-mapping>    
        
    <!-- 加载DispatcherServlet   -->    
    <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:spring-mvc.xml</param-value>    
        </init-param>    
        <load-on-startup>1</load-on-startup>    
        <async-supported>true</async-supported>    
    </servlet>    
    <servlet-mapping>    
        <servlet-name>SpringMVC</servlet-name>    
        <url-pattern>/</url-pattern>    
    </servlet-mapping>    
        
</web-app> 

2.读取applicationContext.xml

之后,会读取 applicationContext.xml,该xml中引用了spring-dao.xml,spring-db.xml,spring-tx.xml。

<?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:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:websocket="http://www.springframework.org/schema/websocket"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
                            http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                            http://www.springframework.org/schema/context
                            http://www.springframework.org/schema/context/spring-context-3.1.xsd
                            http://www.springframework.org/schema/mvc 
                            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd 
                            http://www.springframework.org/schema/websocket http://www.springframework.org/schema/websocket/spring-websocket.xsd
                            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
                            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd                        
                            http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">
	<!-- 自动扫描 读取各个类的spring注解 并注入spring工厂中 使项目支持依赖注入 -->
	<context:component-scan base-package="com" />

	<!-- 导入DAO配置 -->
	<import resource="spring-dao.xml" />

	<!-- 导入数据库配置 -->
	<import resource="spring-db.xml" />

	<!-- 导入事务配置 -->
	<import resource="spring-tx.xml" />
</beans>

3.读取spring-dao.xml

mybatis配置,获取dao层所在的位置。

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                            http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                            http://www.springframework.org/schema/context
                            http://www.springframework.org/schema/context/spring-context-3.1.xsd
                            http://www.springframework.org/schema/mvc
                            http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">


    <!-- DAO接口所在包名,Spring会自动查找其下的类 并且将所有的dao接口封装成beanDefinitions(spring bean) 装载进入spring factory -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--basePackage指定要扫描的包,在此包之下的映射器都会被搜索到。 可指定多个包,包与包之间用逗号或分号分隔-->
        <property name="basePackage" value="com.dao" />
        <!-- spring-db.xml中的 sqlSessionFactory-->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
    </bean>

</beans>

4.读取 spring-db.xml

这里是配置数据库连接与mybatis的相关配置。。

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-3.1.xsd
                        http://www.springframework.org/schema/mvc
                        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

    <!-- 引入配置文件  配置的数据库信息-->
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="classpath:jdbc.properties" />
    </bean>

    <!-- 数据库连接池  -->
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
        <property name="driverClassName" value="$driver" />
        <property name="url" value="$url" />
        <property name="username" value="root" />
        <property name="password" value="root" />
        <!-- 初始化连接大小 -->
        <property name="initialSize" value="$initialSize"></property>
        <!-- 连接池最大数量 -->
        <property name="maxActive" value="$maxActive"></property>
        <!-- 连接池最大空闲 -->
        <property name="maxIdle" value="$maxIdle"></property>
        <!-- 连接池最小空闲 -->
        <property name="minIdle" value="$minIdle"></property>
        <!-- 获取连接最大等待时间 -->
        <property name="maxWait" value="$maxWait"></property>
    </bean>

    <!-- spring和MyBatis完美整合,不需要mybatis的配置映射文件  将mapper.xml解析成SqlSessionFactoryBean并返回,在查询时
           可以获取SqlSessionFactory,并通过代理模调用到-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 引入mysql数据源 -->
        <property name="dataSource" ref="dataSource" />
        <!-- 自动扫描mapping.xml文件 -->
        <property name="mapperLocations" value="classpath:com/mappers/*.xml"></property>
    </bean>

</beans>

这里连接数据库需要知道数据库的账号密码,为了统一管理,将数据库配置放在jdbc.properties。

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/mysql
username=root    
password=root    
initialSize=0    

maxActive=20    
maxIdle=20    
minIdle=1    
maxWait=60000   

5.读取spring-tx.xml

进行事务配置 通过applicationContext.xml读取的配置到这就结束了。

<?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:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/mvc"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-3.1.xsd
                        http://www.springframework.org/schema/mvc
                        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
                        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">

	<!-- (事务管理)transaction manager, use JtaTransactionManager for global tx -->

	<!-- 如果在同一个service类中定义的两个方法, 内层REQUIRES_NEW并不会开启新的事务,save和update中回滚都会导致整个事务的回滚 
		如果在不同的service中定义的两个方法, 内层REQUIRES_NEW会开启新的事务,并且二者独立,事务回滚互不影响 -->
	<!-- <tx:annotation-driven transaction-manager="transactionManager" /> -->
	<!-- Spring编程式事务 -->
	<tx:advice id="txAdvice" transaction-manager="transactionManager">
		<tx:attributes>
			<tx:method name="insertInto" propagation="REQUIRED"
				read-only="false" rollback-for="java.lang.Exception" />
		</tx:attributes>
	</tx:advice>

    <!-- 事务处理管理器 -->
	<bean id="transactionManager"
		class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<!-- 为spring-db.xml中dataSource数据库连接池 -->
		<property name="dataSource" ref="dataSource" />
	</bean>


</beans>

6.读取spring-mvc.xml

该配置主要是配置spring mvc核心功能,如aop,注解扫描位置,拦截器等。

<?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:p="http://www.springframework.org/schema/p"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:task="http://www.springframework.org/schema/task"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context-3.1.xsd
                        http://www.springframework.org/schema/mvc                   
                        http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
                        http://www.springframework.org/schema/task                   
                        http://www.springframework.org/schema/task/spring-task-3.0.xsd
                        http://www.springframework.org/schema/aop                        
                        http://www.springframework.org/schema/aop/spring-aop-3.0.xsd">

	<!--避免IE执行AJAX时,返回JSON出现下载文件 -->
	<bean id="mappingJacksonHttpMessageConverter"
		class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
		<property name="supportedMediaTypes">
			<list>
				<value>text/html;charset=UTF-8</value>
			</list>
		</property>
	</bean>

	<!-- 添加注解驱动 -->
	<mvc:annotation-driven />
	<!-- 设置使用注解的类所在的包 mvc只需要扫描controller就可以-->
	<context:component-scan base-package="com.controller" />

	<!-- 完成请求和注解POJO的映射 -->
	<bean
		class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
		<property name="messageConverters">
			<list>
				<ref bean="mappingJacksonHttpMessageConverter" /> <!-- JSON转换器 -->
			</list>
		</property>
	</bean>
	
	<!-- 定义跳转的文件的前后缀 ,视图模式配置 由于现在基本都是前后端分离 一般没什么软用 -->
	<bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<!-- 这里的配置我的理解是自动给后面action的方法return的字符串加上前缀和后缀,变成一个 可用的url地址 -->
		<property name="prefix" value="/WEB-INF/jsp/" />
		<property name="suffix" value=".jsp" />
	</bean>

	<!-- SpringMVC上传文件时,需要配置MultipartResolver处理器 -->
	<bean id="multipartResolver"
		class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
		<!-- 默认编码 -->
		<property name="defaultEncoding" value="utf-8" />
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