本文描述了web.xml最基本配置方式。
Spring MVC的核心是DispatcherServlet,作爲Spring MVC的前端控制器;
和任何Servlet一樣,我們需要在web.xml文件中配置DispatcherServlet;
下面的描述以這個web.xml爲例:
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 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_5.xsd">
<!-- The definition of the Root Spring Container shared by all Servlets and Filters -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/iSystem-beans.xml,
</param-value>
</context-param>
<!-- Creates the Spring Container shared by all Servlets and Filters -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- Processes application requests -->
<servlet>
<servlet-name>iSystem</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/iSystem-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>iSystem</servlet-name>
<url-pattern>/</url-pattern>
<url-pattern>*.htm</url-pattern>
</servlet-mapping>
</web-app>
在其中的<servlet>標籤下,定義了DispatcherServlet。
重要:在DispatcherServlet載入後,它將從XML文件中載入Spring的應用上下文,這個XML文件的名字取決於Servlet的名字,或者由init-param來指定。
如果我們不設置init-param,形如:
<servlet>
<servlet-name>iSystem</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
這時,DispatcherServlet載入後將默認去加載 /WEB-INF/iSystem-servlet.xml文件,iSystem就是上面定義的servlet-name。
如果沒有這個文件,將會報錯:
java.io.FileNotFoundException: Could not open ServletContext resource [/WEB-INF/iSystem-servlet.xml]
因此我們如果省略init-param的話,需要按下圖放置該xml:
附上模板工程自帶的servlet.xml文件內容:
<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:beans="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
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">
<!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure -->
<!-- Enables the Spring MVC @Controller programming model -->
<annotation-driven />
<!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources directory -->
<resources mapping="/resources/**" location="/resources/" />
<!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory -->
<beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<beans:property name="prefix" value="/WEB-INF/views/" />
<beans:property name="suffix" value=".jsp" />
</beans:bean>
<context:component-scan base-package="com.codeevoship.app" />
</beans:beans>
接下來再爲DispatcherServlet指定需要處理的URL:
<servlet-mapping>
<servlet-name>iSystem</servlet-name>
<url-pattern>/</url-pattern>
<url-pattern>*.htm</url-pattern>
</servlet-mapping>
當然這裏還可以加上*.png、*.gif等等等等……
到這裏DispatcherServlet的配置就完成了,這裏再說說其他內容。
雖然我們已經加載了iSystem-servlet.xml,雖然可以把全項目所有的bean全都定義在這一個xml中……
推薦分層、分模塊分別定義,比如iSystem-security.xml/iSystem-data.xml/iSystem-service.xml……
這就用到了上下文載入器,最常用的ContextLoaderListener:
<!-- Creates the Spring Container shared by all Servlets and Filters -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
這個載入器可以載入除DispatcherServlet載入的配置文件之外的其他上下文配置文件,通過下述方式:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/iSystem-security.xml,
/WEB-INF/iSystem-data.xml,
</param-value>
</context-param>
param-value中就是需要加載的文件,以逗號分隔。以上就是web.xml的最基本配置。
參考:《Spring in Action》
Author:Pirate Leo
blog:http://blog.csdn.net/pirateleo
email:[email protected]
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