深入详解Struts2——struts2的配置文件

struts2的配置文件
web.xml：/WEB-INF/ Web部署描述符，包括所有必需的框架组件
struts.xml：/WEB-INF/classes/ 主要的配置文件，包含result映射、action映射、拦截器配置等
struts.properties：/WEB-INF/classes/ struts2框架属性
struts-default.xml:/WEB-INF/lib/struts2-core.jar struts2提供默认配置
struts-plugin.xml:/WEB-INF/lib/struts2-xxx-plugin.jar struts2框架的插件所用的配置文件
web.xml
struts2框架需要你在web.xml文件中配置一个前端控制器——FilterDispatcher，用于对Struts框架进行初始化以及处理所有的请求。
FilterDispatcher可以包含一些初始化的参数
config：要加载的XML配置文件列表（以逗号分隔）。如果没有设置这个参数，struts2框架默认将加载struts-default.xml、struts-plugin.xml和struts.xml
actionPackages:以逗号分隔的Java包名的列表，struts2框架将扫描这些包中的Action类。
configProviders:实现了ConfigurationProvider接口的Java类的列表(以逗号分隔),ConfiguratioonProvider接口描述了框架的配置，默认情况下，struts2框架使用StrutsXmlConfigurationProvider从XML文档中加载他的配置
例如：

<filter>    <filter-name>struts</filter-name>    <filter-class>        org.apache.struts2.dispatcher.FilterDispatcher    </filter-class>    <init-param>        <param-name>actionPackages</param-name>        <param-value>com.mycompany.myapp.actions</param-value>    </init-param></filter><filter-mapping>    <filter-name>struts</filter-name>    <url-pattern>/*</url-pattern></filter-mapping>

struts-default.xml
struts-default.xml是struts2框架的基础配置文件，位于struts-core-2.0.11.jar中,struts-default.xml文件会自动被包含到struts.xml文件中，以提供标准的配置设置而不需要复制其内容，例如我们在配置strtus.xml时：

<package name="default" extends="struts-default" >

struts-default包就是在struts-default.xml文件中定义的，在这个包中定义了struts2内置的结果类型（包括Servlet转发、Servlet重定向、FreeMarker模板输出、XSTL渲染和ActionChainResult等），内置的拦截器以及由不同拦截器组成的拦截器栈，这些拦截器可以直接使用，也可以作为自定义的拦截器栈的基础。
struts.xml
struts.xml是struts2框架的核心配置文件，在这个配置文件中可以配置作用于action的拦截器、action和result的映射等。
struts.xml文件的元素结构

struts2给出了struts.xml文件的dtd(document type definition,文档类型定义)在struts2的核心类型中有一个struts-2.0.dtd文件，该文件就是struts.xml和struts-default.xml文件的dtd

<?xml version="1.0" encoding="UTF-8"?><!--/* * $Id: struts-2.0.dtd 651946 2008-04-27 13:41:38Z apetrelli $ * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements.  See the NOTICE file * distributed with this work for additional information * regarding copyright ownership.  The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License.  You may obtain a copy of the License at * *  http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied.  See the License for the * specific language governing permissions and limitations * under the License. */--><!-- START SNIPPET: strutsDtd --><!--   Struts configuration DTD.   Use the following DOCTYPE   <!DOCTYPE struts PUBLIC     "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"    "http://struts.apache.org/dtds/struts-2.0.dtd">--><!ELEMENT struts (package|include|bean|constant)*><!ELEMENT package (result-types?, interceptors?, default-interceptor-ref?, default-action-ref?, default-class-ref?, global-results?, global-exception-mappings?, action*)><!ATTLIST package    name CDATA #REQUIRED    extends CDATA #IMPLIED    namespace CDATA #IMPLIED    abstract CDATA #IMPLIED    externalReferenceResolver NMTOKEN #IMPLIED><!ELEMENT result-types (result-type+)><!ELEMENT result-type (param*)><!ATTLIST result-type    name CDATA #REQUIRED    class CDATA #REQUIRED    default (true|false) "false"><!ELEMENT interceptors (interceptor|interceptor-stack)+><!ELEMENT interceptor (param*)><!ATTLIST interceptor    name CDATA #REQUIRED    class CDATA #REQUIRED><!ELEMENT interceptor-stack (interceptor-ref*)><!ATTLIST interceptor-stack    name CDATA #REQUIRED><!ELEMENT interceptor-ref (param*)><!ATTLIST interceptor-ref    name CDATA #REQUIRED><!ELEMENT default-interceptor-ref (#PCDATA)><!ATTLIST default-interceptor-ref    name CDATA #REQUIRED><!ELEMENT default-action-ref (#PCDATA)><!ATTLIST default-action-ref    name CDATA #REQUIRED><!ELEMENT default-class-ref (#PCDATA)><!ATTLIST default-class-ref    class CDATA #REQUIRED><!ELEMENT global-results (result+)><!ELEMENT global-exception-mappings (exception-mapping+)><!ELEMENT action (param|result|interceptor-ref|exception-mapping)*><!ATTLIST action    name CDATA #REQUIRED    class CDATA #IMPLIED    method CDATA #IMPLIED    converter CDATA #IMPLIED><!ELEMENT param (#PCDATA)><!ATTLIST param    name CDATA #REQUIRED><!ELEMENT result (#PCDATA|param)*><!ATTLIST result    name CDATA #IMPLIED    type CDATA #IMPLIED><!ELEMENT exception-mapping (#PCDATA|param)*><!ATTLIST exception-mapping    name CDATA #IMPLIED    exception CDATA #REQUIRED    result CDATA #REQUIRED><!ELEMENT include (#PCDATA)><!ATTLIST include    file CDATA #REQUIRED><!ELEMENT bean (#PCDATA)><!ATTLIST bean    type CDATA #IMPLIED    name CDATA #IMPLIED    class CDATA #REQUIRED    scope CDATA #IMPLIED    static CDATA #IMPLIED    optional CDATA #IMPLIED><!ELEMENT constant (#PCDATA)><!ATTLIST constant    name CDATA #REQUIRED    value CDATA #REQUIRED    ><!-- END SNIPPET: strutsDtd -->

struts-plugin.xml
struts2提供了类型于Eclipse的插件机制来扩展自身功能，插件以Jar包的方式提供
下面我们看一下Spring插件的配置文件

<?xml version="1.0" encoding="UTF-8" ?><!--/* * $Id: struts-plugin.xml 1221225 2011-12-20 12:22:28Z jogep $ * * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements.  See the NOTICE file * distributed with this work for additional information * regarding copyright ownership.  The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License.  You may obtain a copy of the License at * *  http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied.  See the License for the * specific language governing permissions and limitations * under the License. */--><!DOCTYPE struts PUBLIC    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"    "http://struts.apache.org/dtds/struts-2.3.dtd"><struts>    <bean type="com.opensymphony.xwork2.ObjectFactory" name="spring" class="org.apache.struts2.spring.StrutsSpringObjectFactory" />    <!--  Make the Spring object factory the automatic default -->    <constant name="struts.objectFactory" value="spring" />    <constant name="struts.class.reloading.watchList" value="" />    <constant name="struts.class.reloading.acceptClasses" value="" />    <constant name="struts.class.reloading.reloadConfig" value="false" />    <package name="spring-default">        <interceptors>            <interceptor name="autowiring" class="com.opensymphony.xwork2.spring.interceptor.ActionAutowiringInterceptor"/>        </interceptors>    </package>    </struts>