Spring 具体分析 applicationContext.xml 和 spring3-servlet.xml
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web.xml，其绝对路径为： \com.mimvp.homer\src\main\webapp\WEB-INF\web.xml
通过查看log4j的日志可以发现在服务器启动时 applicationContext.xml 是先于spring3-servlet.xml 加载
[org.springframework.web.context.ContextLoader] - Root WebApplicationContext: initialization started May 22, 2017 4:55:25 PM org.apache.catalina.core.ApplicationContext log 信息: Initializing Spring root WebApplicationContext [org.springframework.web.context.support.XmlWebApplicationContext] - Refreshing Root WebApplicationContext: startup date [Mon May 22 16:55:25 CST 2017]; root of context hierarchy [org.springframework.beans.factory.xml.XmlBeanDefinitionReader] - Loading XML bean definitions from class path resource [spring-mybatis.xml] [org.springframework.beans.factory.config.PropertyPlaceholderConfigurer] - Loading properties file from class path resource [jdbc.properties] [org.springframework.web.context.ContextLoader] - Root WebApplicationContext: initialization completed in 5058 ms May 22, 2017 4:55:30 PM org.apache.catalina.core.ApplicationContext log 信息: Initializing Spring FrameworkServlet 'SpringMVC' [org.springframework.web.servlet.DispatcherServlet] - FrameworkServlet 'SpringMVC': initialization started [org.springframework.web.context.support.XmlWebApplicationContext] - Refreshing WebApplicationContext for namespace 'SpringMVC-servlet': startup date [Mon May 22 16:55:30 CST 2017]; parent: Root WebApplicationContext [org.springframework.beans.factory.xml.XmlBeanDefinitionReader] - Loading XML bean definitions from class path resource [spring-mvc.xml] [org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping] - Mapped URL path [/user/showPwd] onto handler 'userController' [org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping] - Mapped URL path [/user/showPwd.*] onto handler 'userController' [org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping] - Mapped URL path [/user/showPwd/] onto handler 'userController' [org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping] - Mapped URL path [/user/showUser] onto handler 'userController' [org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping] - Mapped URL path [/user/showUser.*] onto handler 'userController' [org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping] - Mapped URL path [/user/showUser/] onto handler 'userController' [org.springframework.web.servlet.DispatcherServlet] - FrameworkServlet 'SpringMVC': initialization completed in 1913 ms May 22, 2017 4:55:32 PM org.apache.catalina.startup.HostConfig deployDescriptor 信息: Deployment of configuration descriptor E:\myPro\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\conf\Catalina\localhost\com.mimvp.homer.xml has finished in 13,551 ms May 22, 2017 4:55:32 PM org.apache.coyote.AbstractProtocol start 信息: Starting ProtocolHandler ["http-bio-8080"] May 22, 2017 4:55:32 PM org.apache.coyote.AbstractProtocol start 信息: Starting ProtocolHandler ["ajp-bio-8009"] May 22, 2017 4:55:32 PM org.apache.catalina.startup.Catalina start 信息: Server startup in 21873 ms [com.mimvp.homer.controller.UserController] - /showUser?id=1 [com.mimvp.homer.controller.UserController] - /showPwd?id=3
Spring MVC 加载顺序依次为：
ContextLoader —> XmlWebApplicationContext —> XmlBeanDefinitionReader —> PropertyPlaceholderConfigurer —> ContextLoader （完成）
DispatcherServlet —> XmlWebApplicationContext —> XmlBeanDefinitionReader —> DefaultAnnotationHandlerMapping —> DispatcherServlet （完成）
因此，applicationContext.xml 中已经注册到BeanFactory的bean，在spring3-servlet.xml也是可以使用的，比如在applicationContext.xml中通过context:component-scan扫描了service和dao包，而在spring3-servlet.xml只扫描了web包，但web包中的Controller依然被注入了Service
web.xml各个标签的加载顺序：context-param -> listener -> filter -> servlet
ContextLoaderListener 类源码
package org.springframework.web.context;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
public class ContextLoaderListener extends ContextLoader implements ServletContextListener {
public ContextLoaderListener() {
}
public ContextLoaderListener(WebApplicationContext context) {
super(context);
}
/**
* Initialize the root web application context.
*/
@Override
public void contextInitialized(ServletContextEvent event) {
initWebApplicationContext(event.getServletContext());
}
/**
* Close the root web application context.
*/
@Override
public void contextDestroyed(ServletContextEvent event) {
closeWebApplicationContext(event.getServletContext());
ContextCleanupListener.cleanupAttributes(event.getServletContext());
}
}
ContextLoaderListener 有两个构造函数，继承于ContextLoader类，实现了ContextLoader接口及其两个方法。
web.xml
<?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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<!-- 初始化Spring容器, 并加载Spring配置文件applicationContext.xml -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:com/mimvp/config/applicationContext.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- 使用filter来统一字符编码 -->
<filter>
<filter-name>Set Character Encoding</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>Set Character Encoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 加载DispatcherServlet并加载其的配置文件spring3-servlet.xml -->
<servlet>
<servlet-name>spring3</servlet-name> <!-- 默认找到的是spring3-servlet.xml -->
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<!--
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:com/mimvp/config/spring3-servlet.xml</param-value>
</init-param>
-->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring3</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>spring3</servlet-name>
<url-pattern>*.html</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
启动加载文件 web.xml，会加载配置文件 applicationContext.xml 和 spring3-servlet.xml
applicationContext.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:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd"
default-autowire="byName">
<!-- 注意上面的default-autowire="byName"，如果没有这个声明那么HibernateDaoSupport中的sessionFactory不会被注入 -->
<!-- 约定优于配置-->
<!--
自动扫描组件，包括@Controller,@Service,@Repository这里要把web下面的 controller去除，他们已经在spring3-servlet.xml中配置了,也就是已经加入beanFactory，否则会影响注入
-->
<!-- 还发现了一个问题，就是如果不扫描@Repository，页面都进不去，报404,后来发现是这里的default-autowire和Javabean中@Autowire有冲突。。但最后还是要扫描@Repository，因为要给DAO注入sessionFactory
-->
<context:component-scan base-package="com.mimvp">
<context:exclude-filter type="regex" expression="com.mimvp.web.*" />
</context:component-scan>
<!--
<context:component-scan base-package="com.mimvp.service.impl"></context:component-scan>
<context:component-scan base-package="com.mimvp.dao.impl"></context:component-scan>
-->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://127.0.0.1:3306/ytcdb2?useUnicode=true&characterEncoding=UTF-8"></property>
<property name="username" value="root"></property>
<property name="password" value="root"></property>
<!-- 为了不用每次都去数据库，可以在这里配置连接池，当然，还要引入响应的jar包 -->
<property name="maxActive" value="10"></property>
<property name="maxWait" value="60000"></property>
<property name="maxIdle" value="5"></property>
</bean>
<bean id="sessionFactory"
class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<!-- 由于通过autowire启用了自动装载，所以下面的这个dataSource其实是可以不用写的 ，后面通过ref引用的都是一样的道理-->
<property name="dataSource" ref="dataSource" />
<property name="mappingDirectoryLocations">
<list><!-- 这里直接映射的pojo类所在的包，简单方便不用每次加一个pojo类都需要到这里来添加 -->
<value>classpath:com/mimvp/model</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.connection.autocommit">true</prop>
</props>
</property>
</bean>
<!-- 下面是配置声明式事务管理的，个人感觉比用注解管理事务要简单方便 -->
<bean id="txManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"></property>
</bean>
<!-- advisor包含一个切点和一个通知，而aspect包含多个 -->
<aop:config>
<aop:advisor pointcut="execution(* com.mimvp.service.*Service.*(..))" advice-ref="txAdvice" />
</aop:config>
<tx:advice id="txAdvice" transaction-manager="txManager">
<tx:attributes>
<!-- Service类中以get*,query*等等开头的查询操作只能执行只读事务；对于所有的事务，如果出现异常就回滚 -->
<tx:method name="get*" read-only="true" />
<tx:method name="query*" read-only="true" />
<tx:method name="find*" read-only="true" />
<tx:method name="load*" read-only="true" />
<tx:method name="*" rollback-for="Exception" />
</tx:attributes>
</tx:advice>
</beans>
spring3-servlet.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:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"
default-autowire="byName"> <!-- default-autowire="byName"，约定优于配置 -->
<!--mvc:annotation-driven注册了 RequestMappingHandlerMapping, a RequestMappingHandlerAdapter,and an ExceptionHandlerExceptionResolver
能启动@RequestMapping,@ExceptionHandler, and others注释 -->
<mvc:annotation-driven />
<!-- 把无法mapping到Controller的path交给default servlet handler处理 -->
<mvc:default-servlet-handler />
<!-- 配置静态资源，直接映射到对应的文件夹，不被DispatcherServlet处理而由前面的default-servlet-handler处理，3.04新增功能，需要重新设置spring-mvc-3.0.xsd -->
<mvc:resources mapping="/img/**" location="/img/" />
<mvc:resources mapping="/js/**" location="/js/" />
<mvc:resources mapping="/css/**" location="/css/" />
<mvc:resources mapping="/html/**" location="/html/" />
<!-- ①：对web包中的Controller类进行扫描，以完成Bean创建和自动依赖注入的功能 -->
<!-- 也就是说这里相当于实例化了Controller类并且给它注入了Service的实例？它没有扫描Service的包诶。。 -->
<!-- 因为applicationContext.xml先于本文件加载，所以那边先进行扫描，其实是注入了的，byName通过@Service(...)里面的值进行匹配 -->
<context:component-scan base-package="com.mimvp.web" />
<!--- StringHttpMessageConverter bean -->
<!-- 下面这两个处理器映射默认跟<mvc:annotation-driven />功能几乎是一样的，都能够启用SpringMVC的注解功能，只是如果要添加一些其它功能的时候就进行配置了 -->
<!-- ②：启动Spring MVC的注解功能，完成请求和注解POJO的映射，添加拦截器，类级别的处理器映射 -->
<bean
class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
<property name="interceptors">
<list>
<!-- 用于检查session是否存在 -->
<bean class="com.mimvp.util.MyHandlerInterceptor" />
</list>
</property>
</bean>
<!-- ②：启动Spring MVC的注解功能，完成请求和注解POJO的映射，对有RequestMapping注解的控制器进行HTTP路径、HTTP方法和请求参数解析，
这里 配置了一个基于注解的定制的WebBindingInitializer，解决日期转换问题，方法级别的处理器映射 -->
<bean
class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
<property name="cacheSeconds" value="0" />
<!-- cacheSeconds =0时，则将设置如下响应头数据：
Pragma：no-cache HTTP 1.0的不缓存响应头
Expires：1L useExpiresHeader=true时，HTTP 1.0
Cache-Control ：no-cache useCacheControlHeader=true时，HTTP 1.1
Cache-Control ：no-store useCacheControlNoStore=true时，该设置是防止Firefox缓存 -->
<property name="webBindingInitializer">
<bean class="com.mimvp.util.MyWebBinding" />
</property>
<!-- 配置一下对json数据的转换 -->
<property name="messageConverters">
<list>
<!-- 对@ResponseBody注释的方法生效 -->
<bean
class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"></bean>
<bean
class="org.springframework.http.converter.StringHttpMessageConverter" />
</list>
</property>
</bean>
<!-- 配置对JSP文件的视图解析器 -->
<bean id="freemarkerConfig"
class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">
<property name="templateLoaderPath" value="/WEB-INF/view/" />
<property name="freemarkerSettings">
<props>
<prop key="template_update_delay">0</prop>
<prop key="default_encoding">UTF-8</prop>
<prop key="number_format">0.##########</prop>
<prop key="datetime_format">yyyy-MM-dd HH:mm:ss</prop>
<prop key="classic_compatible">true</prop>
<prop key="template_exception_handler">ignore</prop>
</props>
</property>
</bean>
<bean id="viewResolverJsp"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/view/" />
<property name="suffix" value=".jsp" />
<property name="viewClass"
value="org.springframework.web.servlet.view.InternalResourceView" />
<property name="order" value="1" />
</bean>
<!-- 配置对HTML文件的视图解析器 -->
<!-- 设置freeMarker的配置文件路径 -->
<bean id="freemarkerConfiguration"
class="org.springframework.beans.factory.config.PropertiesFactoryBean">
</bean>
<bean id="viewResolver"
class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
<property name="exposeRequestAttributes" value="true" />
<property name="exposeSessionAttributes" value="true" />
<property name="viewClass">
<value>org.springframework.web.servlet.view.freemarker.FreeMarkerView
</value>
</property>
<property name="cache">
<value>true</value>
</property>
<!-- <property name="allowSessionOverride" value="true" /> -->
<property name="suffix">
<value>.html</value>
</property>
<!-- <property name="viewNames" value="*.html,*.jsp" /> -->
<property name="contentType">
<value>text/html; charset=UTF-8</value>
</property>
<property name="order" value="0" />
</bean>
</beans>
参考推荐：
Java中Dao层、Action层、Service层、Controller层
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转载注明: Spring 具体分析 applicationContext.xml 和 spring3-servlet.xml （米扑博客）