[一]Struts2笔记-初识Struts2.X简单的了解一下

因为最近要做一个项目，最后语言选择的是J2EE为项目编程语言，使用的框架也是行业经典SSH框架，这系列的文章也是我学习SSH的过程，当中有不对的地方还请各位指教。
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          下载密码：访问密码：4qRjds

    struts2.X框架这里就不介绍了，自己百度补脑；
    一：下载struts2.X的框架包，我这里已经打包了，大家可以直接下载，builderpath进自己的项目当中去;

    二：将struts应用到我们的程序当中去：
               我们知道在Servlet当中，Filter过滤器总是在Servlet之前执行，所以要使用struts就得配制一个过滤器，而这个过滤器我们不用去实现，struts已经为我们实现了，我们要做的就是把struts的这个过滤器（org.apache.struts2.dispatcher.FilterDispatcher）配制到我们的web.xml当中去，当配制完成后，我们的请求就会直接转交给struts来处理。
               下面下web.xml配制文件的例子：
          

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="" xmlns:xsi="" xsi:schemaLocation=" /web-app_2_4.xsd">
    <display-name>Zhuanhuan_Demo</display-name>

    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
        <init-param>
            <param-name>struts.action.extension</param-name>
            <param-value>action</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>

    </filter-mapping>

    <welcome-file-list>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
</web-app>

     三：有了上面的那个配制文件，在我们访问程序时，项目流程已经进入了struts，只是我们现在什么也没有做，下面要进行struts的配制，文件名称就是叫做：struts.xml,把这个文件配制到java Resoureces项目目录下的src根目录下即可：

     四：在使用struts之前我们先了解一下struts的配制文件，也就是struts.xml文件，他的文件标准如下：

<?xml version="1.0" encoding="UTF-8"?>
<!--
/*
 * $Id$
 *
 * 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"
    "">
-->

<!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 -->

从他的DTD结构文件当中可以了解到struts配制文件根元素无非就是这几个：
<!ELEMENT struts (package|include|bean|constant)*>.....

如果不懂DTD文件，请自行百度学习
下面是一个struts.xml配制文件的框架：

<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "">
<struts>
    <package name="main" extends="struts-default">

    </package>
</struts>

    通过上面的简单的介绍，可以大概的了解struts框架配制流程，下面通过一个程序（用户登陆来更加具体的了解struts框架的使用和他的执行流程）