JavaEE中web.xml中的load-on-startup属性

本文解析了load-on-startup元素的作用及配置方法,详细介绍了它如何控制servlet的加载顺序,并通过一个SpringMVC分发器的具体示例进行说明。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

1)load-on-startup元素标记容器是否在启动的时候就加载这个servlet(实例化并调用其init()方法)。

2)它的值必须是一个整数,表示servlet应该被载入的顺序。当值为0或者大于0时,表示容器在应用启动时就加载并初始化这个servlet;

3)当值小于0或者没有指定时,则表示容器在该servlet被选择时才会去加载。

4)正数的值越小,该servlet的优先级越高,应用启动时就越先加载。

5)当值相同时,容器就会自己选择顺序来加载。

看一个配置SpringMVC分发器的例子:

<servlet>
<servlet-name>springServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>springServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>

<load-on-startup>x</load-on-startup>中x的取值1,2,3,4,5代表的是优先级,而非启动延迟时间。

原帖地址:http://www.blogjava.net/Nirvana/archive/2012/09/19/388085.html


<?xml version="1.0" encoding="UTF-8" standalone="no"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="3.1" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"> <context-param> <param-name>metadata-complete</param-name> <param-value>true</param-value> </context-param> <servlet> <servlet-name>exampleServlet</servlet-name> <servlet-class>com.example.ExampleServlet</servlet-class> </servlet> <servlet> <description>generated-servlet</description> <servlet-name>KuCun2 Servlet</servlet-name> <servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:KuCun2-web-context.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet> <description>generated-resources-servlet</description> <servlet-name>Resource Servlet</servlet-name> <servlet-class> org.springframework.js.resource.ResourceServlet </servlet-class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>exampleServlet</servlet-name> <url-pattern>/example</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>Resource Servlet</servlet-name> <url-pattern>/resources/*</url-pattern> </servlet-mapping> <listener> <listener-class> org.springframework.web.context.ContextLoaderListener </listener-class> </listener> <listener> <listener-class> org.springframework.web.context.request.RequestContextListener </listener-class> </listener> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param> </web-app>
06-21
<?xml version="1.0" encoding="UTF-8"?> <web-app version="2.3" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_3.xsd"> <display-name>Archetype Created Web Application</display-name> <welcome-file-list> <welcome-file>login.jsp</welcome-file> </welcome-file-list> <!-- 配置spring资源 --> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:application.xml</param-value> </context-param> <!-- 乱码问题 --> <filter> <filter-name>CharacterEncodingFilter</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> </filter> <init-param> <param-name>forceEncoding</param-name> <param-value>true</param-value> </init-param> <filter-mapping> <filter-name>CharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <!--配置springmvc DispatcherServlet接收到的http请求通过DispatcherServlet进行分发。--> <servlet> <servlet-name>note</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <!--Sources标注的文件夹下需要新建一个spring文件夹--> <param-name>contextConfigLocation</param-name> <param-value>classpath:spring/spring-mvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>note</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping> </web-app>检查代码修改正确
06-07
评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值