SpringMVC项目中web.xml中的节点加载顺序问题,之前以为web.xml中就是一些配置信息,和节点的顺序没有关系,后来才发现初始化时的加载顺序是和节点的顺序相关的。
完整的web.xml文件内容:
<?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_3_0.xsd" id="WebApp_ID" version="3.0">
<!--
Spring ApplicationContext配置文件的路径,可使用通配符,多个路径用,号分隔
此参数用于后面的Spring-Context loader
-->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:/spring/*.xml</param-value>
</context-param>
<filter>
<filter-name>encodingFilter</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>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter>
<filter-name>authenticationFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>authenticationFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter>
<filter-name>authorizationFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>authorizationFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<listener>
<listener-class>com.auth.spring.listener.SpringLoaderListener</listener-class>
</listener>
<listener>
<listener-class>com.abc.mobile.web.MobileLoader</listener-class>
</listener>
<listener>
<listener-class>
com.auth.listener.HttpSessionManager
</listener-class>
</listener>
<!-- 防止spring内存溢出监听器 -->
<listener>
<listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>
</listener>
<listener>
<listener-class>com.abc.conference.context.RpcManager</listener-class>
</listener>
<servlet>
<servlet-name>Action</servlet-name>
<servlet-class>com.abc.conference.apis.Action</servlet-class>
</servlet>
<servlet>
<servlet-name>t1</servlet-name>
<servlet-class>com.abc.base.web.init.BaseDataServlet</servlet-class>
<!-- 如果需要自动加载,加下面一句 -->
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>Action</servlet-name>
<url-pattern>/public/Action</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>middleware</servlet-name>
<servlet-class>com.abc.mobile.web.ActionProxy</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>middleware</servlet-name>
<url-pattern>/public/middleware</url-pattern>
</servlet-mapping>
<!-- spring mvc servlet -->
<!-- springmvc 配置 -->
<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*:/springmvc-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springmvc</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<servlet>
<description></description>
<display-name>ServletLoader</display-name>
<servlet-name>ServletLoader</servlet-name>
<servlet-class>com.abc.conference.context.ServletLoader</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet>
<display-name>middlewareInit</display-name>
<servlet-name>middlewareInit</servlet-name>
<servlet-class>com.abc.middleware.init.MiddlewareServletLoader</servlet-class>
<load-on-startup>2</load-on-startup>
</servlet>
<welcome-file-list>
<welcome-file>/index.jsp</welcome-file>
</welcome-file-list>
<!-- 配置session超时时间,单位分钟 -->
<session-config>
<session-timeout>15</session-timeout>
</session-config>
</web-app>
因为在Action中用到了一些静态变量,而这个静态变量是在BaseDataServlet中初始化的,所以如果
<servlet>
<servlet-name>t1</servlet-name>
<servlet-class>com.abc.base.web.init.BaseDataServlet</servlet-class>
<!-- 如果需要自动加载,加下面一句 -->
<load-on-startup>1</load-on-startup>
</servlet>
配置节点,在Action:
<servlet-mapping>
<servlet-name>Action</servlet-name>
<url-pattern>/public/Action</url-pattern>
</servlet-mapping>
节点之后的话,那调用静态变量的时候,静态变量的值就是Null,因为这时还没有初始化呢。