为什么Spring Context被加载两次? [英] Why Spring Context is loaded twice?

问题描述

我有一个带有Spring和Spring安全性的Web项目. 我的web.xml:

I have web project with Spring and Spring security. My web.xml:

    <web-app 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_3_0.xsd"
         version="3.0" >
        <display-name>BillBoard
        </display-name>
        <session-config>
            <session-timeout>
                30
            </session-timeout>
        </session-config>
        <listener>
            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
        </listener>
        <listener>
            <listener-class>org.springframework.security.web.session.HttpSessionEventPublisher</listener-class>
        </listener>
        <context-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:security-config.xml classpath:billboard-servlet.xml</param-value>
        </context-param>
        <servlet>
            <servlet-name>billboard</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>classpath:security-config.xml classpath:billboard-servlet.xml</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>

        </servlet>
        <servlet-mapping>
            <servlet-name>billboard</servlet-name>
            <url-pattern>*.html</url-pattern>
        </servlet-mapping>
        <filter>
            <filter-name>springSecurityFilterChain</filter-name>
            <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
        </filter>

        <filter-mapping>
            <filter-name>springSecurityFilterChain</filter-name>
            <url-pattern>/*</url-pattern>
        </filter-mapping>
    </web-app>

在服务器日志中，我看到Spring上下文被加载了两次(Spring Bean初始化，数据库创建...).第一次使用DispatcherServlet进行此操作，第二次使用ContextLoaderListener.我该如何解决?

In server logs I see Spring context is loaded twice (spring bean initialization, database createtion...). At first time DispatcherServlet does it, and at the secont time ContextLoaderListener. How can I fix it?

在此教程中，我看到如果提供了contextParam，那么servlet不需要init-params.但是，如果我删除了初始化参数，则会出现错误:"org.apache.catalina.LifecycleException:org.apache.catalina.LifecycleException:java.io.FileNotFoundException:无法打开ServletContext资源[/WEB-INF/billboard-servlet.xml] ". Dispather servlet在默认位置找到上下文配置.

In this tutorial I see that if contextParam is presented then servlet init-params are not required. But if I remove init params I have error: "org.apache.catalina.LifecycleException: org.apache.catalina.LifecycleException: java.io.FileNotFoundException: Could not open ServletContext resource [/WEB-INF/billboard-servlet.xml]". Dispather servlet finds context-configuration in default location.

推荐答案

您仍然需要servlet上下文:

You still need a context for your servlet:

在初始化DispatcherServlet时，Spring MVC在Web应用程序的WEB-INF目录中查找名为[servlet-name] -servlet.xml的文件，并创建在那里定义的bean，从而覆盖任何使用以下命令定义的bean的定义.在全球范围内具有相同的名称.

Upon initialization of a DispatcherServlet, Spring MVC looks for a file named [servlet-name]-servlet.xml in the WEB-INF directory of your web application and creates the beans defined there, overriding the definitions of any beans defined with the same name in the global scope.

不过，您无需在ContextLoaderListener中将其加载为context-param.

You don't need to load it as context-param in the ContextLoaderListener though.

只需将security-config.xml保留为context-param(因为每个应用程序的安全性是全局的)，就必须将security-config.xml保留在那里，而将billboard-servlet.xml保留为servlet的contextConfigLocation，它应该可以工作.

Just leave the security-config.xml as context-param (it has to go there, as security is global per application), and billboard-servlet.xml as contextConfigLocation of your servlet and it should work.

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