Spring MVC web app:应用程序上下文启动两次

Question

我正在开发一个Spring MVC REST API。一切正常，这很棒，但我从日志中注意到，每次我重启应用程序时，applicationContext都会加载两次:一次是tomcat加载war文件，第二次是客户端第一次访问web应用程序。

我将举几个例子：

在我启动tomcat之后：

Apr 11, 2013 10:14:35 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.32
Apr 11, 2013 10:14:36 AM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring root WebApplicationContext
2013-04-11 10:14:36 INFO  ContextLoader:273 - Root WebApplicationContext:     initialization started
2013-04-11 10:14:36 INFO  XmlWebApplicationContext:510 - Refreshing Root     WebApplicationContext: startup date [Thu Apr 11 10:14:36 EDT 2013]; root of context hierarchy
2013-04-11 10:14:36 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions     from ServletContext resource [/WEB-INF/mvc-dispatcher-servlet.xml]
2013-04-11 10:14:36 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-general.xml]
2013-04-11 10:14:37 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-db.xml]
2013-04-11 10:14:37 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-security.xml]
2013-04-11 10:14:37 INFO  SpringSecurityCoreVersion:33 - You are running with Spring Security Core 3.1.3.RELEASE
2013-04-11 10:14:37 INFO  SecurityNamespaceHandler:59 - Spring Security 'config' module version is 3.1.3.RELEASE

..。

然后在我做第一个API调用的时候：

INFO: Initializing Spring FrameworkServlet 'mvc-dispatcher'
2013-04-11 10:15:25 INFO  DispatcherServlet:455 - FrameworkServlet 'mvc-dispatcher': initialization started
2013-04-11 10:15:25 INFO  XmlWebApplicationContext:510 - Refreshing WebApplicationContext for namespace 'mvc-dispatcher-servlet': startup date [Thu Apr 11     10:15:25 EDT 2013]; parent: Root WebApplicationContext
2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from ServletContext resource [/WEB-INF/mvc-dispatcher-servlet.xml]
2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-general.xml]
2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-db.xml]
2013-04-11 10:15:25 INFO  XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-security.xml]
2013-04-11 10:15:25 INFO  SecurityNamespaceHandler:59 - Spring Security 'config' module version is 3.1.3.RELEASE

这肯定不是正常行为吧？？我的web.xml看起来像这样：

">http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<display-name>REST API</display-name>

<!-- Servlets -->
<servlet>
    <servlet-name>mvc-dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>mvc-dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
</context-param>

<!-- filters -->
<filter>
    <filter-name>httpMethodFilter</filter-name>
    <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>httpMethodFilter</filter-name>
    <servlet-name>mvc-dispatcher</servlet-name>
</filter-mapping>
<filter>
    <filter-name>etagFilter</filter-name>
    <filter-class>org.springframework.web.filter.ShallowEtagHeaderFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>etagFilter</filter-name>
    <servlet-name>mvc-dispatcher</servlet-name>
</filter-mapping>
<filter>
    <filter-name>CompressingFilter</filter-name>
    <filter-class>com.planetj.servlet.filter.compression.CompressingFilter</filter-class>
    <init-param>
        <param-name>debug</param-name>
        <param-value>false</param-value>
    </init-param>
    <init-param>
        <param-name>statsEnabled</param-name>
        <param-value>false</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>CompressingFilter</filter-name>
    <servlet-name>mvc-dispatcher</servlet-name>
</filter-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>



<!-- listeners -->
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

​

Answer 1

mvc-dispatcher正在加载2x，因为这是您定义它的方式

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
</context-param>

和在

<servlet>
    <servlet-name>mvc-dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>mvc-dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

第一种方法通常用于加载类似“全局”或“根”上下文的内容，您可以将多个servlet上下文共享的所有bean/资源放在其中。

第二种方法通常用于加载特定的servlet上下文。正如第一个answer in this post所指出的，它使用命名约定来查找mvc-dispatcher配置文件，因此您不需要显式地定义它。

您是否在mvc-dispatcher-servlet.xml中定义了所有内容？如果是这样，您可以删除

<context-param>
  ..
</context-param>

定义，否则您可以(为了将来的可维护性，我推荐)将您的配置分离到多个文件中。然后，将共享bean/资源加载到类似于root-context.xml的文件中(通过第一种方法)，并在servletname-servlet.xml下为每个servlet上下文指定特定的配置。