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java web项目的web.xml详细说明【轻巧理解web.xml】

2012-09-11 
java web项目的web.xml详细说明【轻松理解web.xml】?声明:本文来自其他作者,具体出处忘记了,表示对作者抱歉。

java web项目的web.xml详细说明【轻松理解web.xml】

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声明:本文来自其他作者,具体出处忘记了,表示对作者抱歉。

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1.常规配置:

此处参照CSDN博客:http://blog.csdn.net/cocojiji5/article/details/1601428

每一个站的WEB-INF下都有一个web.xml的设定文件,它提供了我们站台的配置设定.

web.xml定义:
?.站台的名称和说明
?.针对环境参数(Context)做初始化工作
?.Servlet的名称和映射
?.Session的设定
?.Tag library的对映
?.JSP网页设定
?.Mime Type处理
?.错误处理
?.利用JDNI取得站台资源

要了解web.xml的设定值,必须了解它的schema,从web.xml中知道它的schema是由SumMicrosystems公司定制的,如果你想更为详细的了解它,
可以到http://java.sun.com/xml/ns/j2ee/web-mapp_2_5.xsd网页,那里有更为详细的介绍。这里我介绍我们平常见得最都的.
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<?xml version="1.0" encoding="ISO-8859-1"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
?? xmlns="http://java.sun.com/xml/ns/javaee"xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
?? xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
?? version="2.5">

<web-app>
这是一般在写XML时所做的声明,定义了XML的版本,编码格式,还有重要的指明schema的来源,为http://java.sun.com/xml/ns/j2ee
/web-app_2_5.xsd.


<description>,<display-name>,<icon>
____________________________________________

<description>站台描述</discription>
对站台做出描述.

<display-name>站台名称</display-name>
定义站台的名称.

<icon>
icon元素包含small-icon和large-icon两个子元素.用来指定web站台中小图标和大图标的路径.
<small-icon>/路径/smallicon.gif</small-icon>
small-icon元素应指向web站台中某个小图标的路径,大小为16 X 16 pixel,但是图象文件必须为GIF或JPEG格式,扩展名必须为:.gif或
.jpg.

<large-icon>/路径/largeicon-jpg</large-icon>
large-icon元素应指向web站台中某个大图表路径,大小为32 X 32 pixel,但是图象文件必须为GIF或JPEG的格式,扩展名必须为; gif
或jpg.


范例:
<display-name>Develop Example</display-name>
<description>JSP 2.0 Tech Book's Examples</description>
<icon>
?? <small-icon>/images/small.gif</small-icon>
?? <large-icon>/images/large.gir</large-icon>
</icon>


<distributable>
______________________________________

<distributable>
distributable 元素为空标签,它的存在与否可以指定站台是否可分布式处理.如果web.xml中出现这个元素,则代表站台在开发时已经
被设计为能在多个JSP Container 之间分散执行.
范例:
<distributable/>

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<context-param>
___________________________________

<context-param>
context-param 元素用来设定web站台的环境参数(context),它包含两个子元素:
param-name和param-value.
<param-name>参数名称</param-name>
设定Context名称
<param-value>值</param-value>
设定Context名称的值
</context-param>
范例:
<context-param>
?? <param-name>param_name</param-name>
?? <param-value>param_value</param-value>
</context-param>
此所设定的参数,在JSP网页中可以使用下列方法来取得:
${initParam.param_name}
若在Servlet可以使用下列方法来获得:
String param_name=getServletContext().getInitParamter("param_name");

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<filter>
_________________________________
filter元素用来声明filter的相关设定.filter元素除了下面介绍的的子元素之外,还包括<servlet>介绍过的<icon>,<display-name>
,<description>,<init-param>,其用途一样.
<filter-name>Filter的名称</filter-name>
定义Filter的名称.
<filter-class>Filter的类名称</filter-class>
定义Filter的类名称.例如:com.foo.hello
</filter>


范例:
<filter>
? <filter-name>setCharacterEncoding</filter-name>
?<filter-class>coreservlet.javaworld.CH11.SetCharacterEncodingFilter</filter-class>
? <init-param>
???? <param-name>encoding</param-name>
???? <param-value>GB2312</param-value>
? </init-param>
</filter>


<filter-mapping>
______________________________________
<filter-mapping>
filter-mapping 元素的两个主要子元素filter-name和url-pattern.用来定义Filter所对应的URL.
<filter-name>Filter的名称</filter-name>
定义Filter的名称.
<url-pattern>URL</url-pattern>
Filter所对应的RUL.例如:<url-pattern>/Filter/Hello</url-pattern>

<servlet-name>Servlet的名称<servlet-name>
定义servlet的名称.
<dispatcher>REQUEST|INCLUDE|FORWARD|ERROR</disaptcher>
设定Filter对应的请求方式,有RQUEST,INCLUDE,FORWAR,ERROR四种,默认为REQUEST.
</filter-mapping>
范例:
<filter-mapping>
?? <filter-name>GZIPEncoding</filter-name>
?? <url-pattern>/*</url-pattern>
</filter-mapping>

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<listener>
___________________________________________
<listener>
listener元素用来定义Listener接口,它的主要子元素为<listener-class>
<listen-class>Listener的类名称</listener-class>
定义Listener的类名称.例如: com.foo.hello
<listener>
范例:
<listener>
?<listener-class>coreservlet.javaworld.CH11.ContenxtListener</listener-class>
</listener>

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<servlet-mapping>
_____________________________________________
servlet-mapping元素包含两个子元素servlet-name和url-pattern.用来定义servlet所对应URL.
<servlet-name>Servlet的名称</servlet-name>
定义Servlet的名称.
<url-pattern>Servlet URL</url-pattern>
定义Servlet所对应的RUL.例如:<url-pattern>/Servlet/Hello</url-pattern>
</servlet-mapping>
范例:
<servlet-mapping>
?? <servlet-name>LoginChecker</servlet-name>
?? <url-pattern>/LoginChecker</url-pattern>
</servlet-mapping>


<session-cofing>
__________________________________
<session-config>
session-config包含一个子元素session-timeout.定义web站台中的session参数.
<session-timeout>分钟</session-timeout>
定义这个web站台所有session的有效期限.单位为分钟.
</session-config>
范例:
<session-config>
?? <session-timeout>20</session-timeout>
</session-config>


<mime-mapping>
___________________________________________________
<mima-mapping>
mime-mapping包含两个子元素extension和mime-type.定义某一个扩展名和某一MIME Type做对映.
<extension>扩展名名称</extension>
扩展名称
<mime-type>MIME格式</mime-type>
MIME格式.
</mime-mapping>
范例:
<mime-mapping>
?? <extension>doc</extension>
?? <mime-type>application/vnd.ms-word</mime-type>
</mime-mapping>
<mime-mapping>
?? <extension>xls</extension>
?? <mime-type>application/vnd.ms-excel</mime-type>
</mime-mapping>
<mime-mapping>
?? <extension>ppt</extesnion>
?? <mime-type>application/vnd.ms-powerpoint</mime-type>
</mime-mapping>

说明:<mime-mapping>主要是用在下载的地方,如果你的web项目没有下载这个模块,<mime-mapping>可以不用配置的,

如果有下载的模块,但是没有配置,那么别人点下载的时候,会打开一个新窗口,而且多数情况下是乱码。有该配置后,就可以用迅雷,flashGet等来下载,也可以目标另存为来下载文件,

在我的之前博客:2010-11-12 “下载的原理" 里面已有详细介绍给块。


<welcome-file-list>
_____________________________________________
<welcome-file-list>
welcome-file-list包含一个子元素welcome-file.用来定义首页列单.
<welcome-file>用来指定首页文件名称</welcome-flie>
welcome-file用来指定首页文件名称.我们可以用<welcome-file>指定几个首页,而服务器会依照设定的顺序来找首页.
范例:
<welcome-file-list>
? <welcome-file>index.jsp</welcome-file>
? <welcome-file>index.htm</welcome-file>
</welcome-file-list>

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<error-page>
_________________________
<error-page>
error-page元素包含三个子元素error-code,exception-type和location.将错误代码(Error Code)或异常(Exception)的种类对应
到web站台资源路径.
<error-code>错误代码</error-code>
HTTP Error code,例如: 404
<exception-type>Exception</exception-type>
一个完整名称的Java异常类型
<location>/路径</location>
在web站台内的相关资源路径
</error-page>
范例:
<error-page>
?? <error-code>404</error-code>
?? <location>/error404.jsp</location>
</error-page>
<error-page>
?? <exception-type>java.lang.Exception</exception-type>
?? <location>/except.jsp</location>
</error-page>

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<jsp-config>
_______________________________________________
<jsp-config>
jsp-config元素主要用来设定JSP的相关配置,<jsp:config>包括<taglib>和<jsp-property-group>两个子元素.其中<taglib>元素
在JSP 1.2时就已经存在了;而<jsp-property-group>是JSP 2.0新增的元素.

<taglib>
taglib元素包含两个子元素taglib-uri和taglib-location.用来设定JSP网页用到的Tag Library路径.
<taglib-uri>URI</taglib-uri>
?? taglib-uri定义TLD文件的URI,JSP网页的taglib指令可以经由这个URI存取到TLD文件.
<taglib-location>/WEB-INF/lib/xxx.tld</taglib-laction>
?? TLD文件对应Web站台的存放位置.
</taglib>

<jsp-property-group>
jsp-property-group元素包含8个元素,分别为:
<description>Description</descrition>
此设定的说明

<display-name>Name</display-name>
此设定的名称

<url-pattern>URL</url-pattern>
设定值所影响的范围,如:/CH2 或者/*.jsp

<el-ignored>true|false</el-ignored>
若为true,表示不支持EL语法.

<scripting-invalid>true|false</scripting-invalid>
若为true表示不支持<%scription%>语法.

<page-encoding>encoding</page-encoding>
设定JSP网页的编码

<include-prelude>.jspf</include-prelude>
设置JSP网页的抬头,扩展名为.jspf

<include-coda>.jspf</include-coda>
设置JSP网页的结尾,扩展名为.jspf
</jsp-property-group>
</jsp-config>
范例:
<jsp-config>
<taglib>
?? <taglib-uri>Taglib</taglib-uri>
??<taglib-location>/WEB-INF/tlds/MyTaglib.tld</taglib-location>
</taglib>
<jsp-property-group>
?? <description>
????? Special property group for JSP Configuration JSPexample.
?? </description>
?? <display-name>JSPConfiguration</display-name>
?? <uri-pattern>/*</uri-pattern>
?? <el-ignored>true</el-ignored>
?? <page-encoding>GB2312</page-encoding>
?? <scripting-inivalid>true</scripting-inivalid>
?? ............
</jsp-property-group>
</jsp-config>

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<resource-ref>
________________________________________________
<resource-ref>
resource-ref元素包括五个子元素description,res-ref-name,res-type,res-auth,res-sharing-scope.利用JNDI取得站台可
利用资源.
<description>说明</description>
资源说明

<rec-ref-name>资源名称</rec-ref-name>
资源名称

<res-type>资源种类</res-type>
资源种类

<res-auth>Application|Container</res-auth>
资源由Application或Container来许可

<res-sharing-scope>Shareable|Unshareable</res-sharing-scope>
?资源是否可以共享.默认值为 Shareable
范例:
<resource-ref>
?? <description>JNDI JDBC DataSource of JSPBook</description>
?? <res-ref-name>jdbc/sample_db</res-ref-name>
?? <res-type>javax.sql.DataSoruce</res-type>
?? <res-auth>Container</res-auth>
</resource-ref>

这些都是些比较常用的,详细可以登录: http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd

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2.以前的一个项目Spring MVC + freemarker的web.xml的完整配置:

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
?? xmlns="http://java.sun.com/xml/ns/javaee"xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
?? xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
?? version="2.5">


?<display-name>AAAA Web Application</display-name>

?<context-param>
??<param-name>contextConfigLocation</param-name>
??<param-value>
???classpath*:applicationContext-dao.xml
???classpath*:applicationContext-datasource.xml
???classpath:applicationContext-resources.xml
???classpath*:applicationContext-service.xml
???/WEB-INF/applicationContext-filter.xml
???/WEB-INF/applicationContext-security.xml
??????? </param-value>
?</context-param>

?<context-param>
??<param-name>webAppRootKey</param-name>??
??<param-value>AAAA_web.root</param-value>??
?</context-param>??

?<context-param>
??<param-name>log4jConfigLocation</param-name>
??<param-value>classpath:log4j.properties</param-value>
?</context-param>

?<filter>
??<filter-name>encodingFilter</filter-name>
??<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
??<init-param>
???<param-name>encoding</param-name>
???<param-value>UTF-8</param-value>
??</init-param>
??<init-param>
???<param-name>forceEncoding</param-name>
???<param-value>true</param-value>
??</init-param>
?</filter>

?<filter-mapping>
??<filter-name>encodingFilter</filter-name>
??<url-pattern>/*</url-pattern>
?</filter-mapping>
?
?
?<!-- 分发服务器服务、和订购消息服务、暂时屏蔽
?<filter>
??<filter-name>AAAANotifyFilter</filter-name>
??<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
?</filter>
?<filter-mapping>
??<filter-name>AAAANotifyFilter</filter-name>
??<url-pattern>/notify.html</url-pattern>
?</filter-mapping>
?
?<filter>
??<filter-name>AAAACallbackFilter</filter-name>
??<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
?</filter>
?<filter-mapping>
??<filter-name>AAAACallbackFilter</filter-name>
??<url-pattern>/callback.shtml</url-pattern>
?</filter-mapping>
? -->
?<!--
?? <filter>
?? <filter-name>openSessionInViewFilter</filter-name>
?? <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
?? </filter>
?? <filter-mapping>
?? <filter-name>openSessionInViewFilter</filter-name>
?? <servlet-name>dispatcher</servlet-name>
?? </filter-mapping>
?-->
?<listener>
??<listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
?</listener>

?<listener>
??<listener-class>
???????????org.springframework.web.util.IntrospectorCleanupListener</listener-class>
?</listener>

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

?<servlet>
??<servlet-name>dispatcher</servlet-name>
??<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
??<load-on-startup>1</load-on-startup>
?</servlet>

?<servlet-mapping>
??<servlet-name>dispatcher</servlet-name>
??<url-pattern>*.html</url-pattern>
??<url-pattern>*.shtml</url-pattern>
??<url-pattern>/track/*</url-pattern>
?</servlet-mapping>

?<!--?<servlet>-->
?<!--??? <servlet-name>default</servlet-name>-->
?<!--???<servlet-class>org.mortbay.jetty.servlet.DefaultServlet</servlet-class>-->
?<!--??? <init-param>-->
?<!--?????<param-name>useFileMappedBuffer</param-name>-->
?<!--?????<param-value>false</param-value>-->
?<!--??? </init-param>-->
?<!--???<load-on-startup>0</load-on-startup>-->
?<!--? </servlet>-->


?<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>*.shtml</url-pattern>
?</filter-mapping>

?<session-config>
??<session-timeout>30</session-timeout>
?</session-config>

?<error-page>
??<error-code>500</error-code>
??<location>/500.html</location>
?</error-page>
?<error-page>
??<error-code>403</error-code>
??<location>/403.html</location>
?</error-page>
</web-app>

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3.以前的SSH架构 ,加了spring,加了freemarker的web.xml配置:

<?xml version="1.0"encoding="UTF-8"?>
<web-app id="WebApp_ID" 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/javaeehttp://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">

?<display-name>网创运营平台</display-name>
?<context-param>
? <!-- spring配置文件 -->
? <param-name>contextConfigLocation</param-name>
? <param-value>classpath:applicationContext.xml</param-value>
?</context-param>

?<!--Spring Security
? <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>
?OpenSessionInViewFilter? -->
?<!-- 字符编码过滤器 -->
???? <filter>
??? <filter-name>encodingFilter</filter-name>
???<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
??? <init-param>
????? <param-name>encoding</param-name>
????? <param-value>UTF-8</param-value>
??? </init-param>
??? <init-param>
?????<param-name>forceEncoding</param-name>
????? <param-value>true</param-value>
??? </init-param>
? </filter>
? <filter-mapping>
??? <filter-name>encodingFilter</filter-name>
??? <url-pattern>/*</url-pattern>
? </filter-mapping>
?
?<filter>
? <filter-name>hibernateFilter</filter-name>
?<filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class>
? <init-param>
?? <param-name>singleSession</param-name>
?? <param-value>true</param-value>
? </init-param>
?</filter>
?<!-- System Auth Filter -->
?<filter>
? <filter-name>AuthFilter</filter-name>
? <filter-class>cn.com.ecenter.system.interceptors.AuthFilter</filter-class>
?</filter>
?<filter>
? <filter-name>osivFilter</filter-name>
?<filter-class>cn.com.ecenter.system.util.OpenSessionInViewFilter</filter-class>
? <init-param>
?? <param-name>singleSession</param-name>
?? <param-value>true</param-value>
? </init-param>
?</filter>
?<!-- struts2 -->
?<filter>
? <filter-name>struts2</filter-name>
?<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
? <init-param>
?? <param-name>actionPackages</param-name>
?? <param-value>cn.com.ecenter.dragonclaws.action</param-value>
? </init-param>
?</filter>
?<filter-mapping>
? <filter-name>hibernateFilter</filter-name>
? <url-pattern>*.action</url-pattern>
?</filter-mapping>
?<filter-mapping>
? <filter-name>hibernateFilter</filter-name>
? <url-pattern>*.jsp</url-pattern>
?</filter-mapping>
?
? <filter-mapping>
? <filter-name>hibernateFilter</filter-name>
? <url-pattern>*.shtml</url-pattern>
?</filter-mapping>
?
?
?<filter-mapping>
? <filter-name>AuthFilter</filter-name>
? <url-pattern>*.action</url-pattern>
?</filter-mapping>
?
? <filter-mapping>
? <filter-name>AuthFilter</filter-name>
? <url-pattern>*.shtml</url-pattern>
?</filter-mapping>
?
? <filter-mapping>
? <filter-name>AuthFilter</filter-name>
? <url-pattern>/pages/*</url-pattern>
?</filter-mapping>
?
?? <filter-mapping>
? <filter-name>AuthFilter</filter-name>
? <url-pattern>/views/*</url-pattern>
?</filter-mapping>
?
?<filter-mapping>
? <filter-name>osivFilter</filter-name>
? <url-pattern>/system/*</url-pattern>
?</filter-mapping>
?<filter-mapping>
? <filter-name>struts2</filter-name>
? <url-pattern>*.action</url-pattern>
?</filter-mapping>
?<filter-mapping>
? <filter-name>struts2</filter-name>
? <url-pattern>*.jsp</url-pattern>
?</filter-mapping>
?
?
?<!-- Spring Framework -->
?<listener>
? <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
?</listener>
?<!-- ServletContextListener,需要服务器启动时加载的 -->
?<listener>
?<listener-class>cn.com.ecenter.dragonclaws.web.WebContextListerner</listener-class>
?</listener>
?
?<!-- 兼容ftl -->
? <servlet>
??? <servlet-name>dispatcher</servlet-name>
???<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
??? <load-on-startup>1</load-on-startup>
? </servlet>
? <servlet-mapping>
??? <servlet-name>dispatcher</servlet-name>
??? <url-pattern>*.shtml</url-pattern>
??? <url-pattern>/track/*</url-pattern>
? </servlet-mapping>
?
?
?
?<servlet>
? <display-name>ElFinderServlet</display-name>
? <servlet-name>ElFinderServlet</servlet-name>
? <servlet-class>cn.com.ecenter.elfinder.ElFinderServlet</servlet-class>
?</servlet>
?? <servlet>
?<servlet-name>ShowImageServlet</servlet-name>
???<servlet-class>cn.com.ecenter.dragonclaws.util.ShowImageServlet</servlet-class>
?</servlet>
?<servlet-mapping>
? <servlet-name>ElFinderServlet</servlet-name>
? <url-pattern>/ElFinderServlet</url-pattern>
?</servlet-mapping>
?<servlet-mapping>
?? <servlet-name>ShowImageServlet</servlet-name>
?? <url-pattern>/ShowImageServlet</url-pattern>
?</servlet-mapping>
?
?<!-- jFreeChart add by xiongt 20110616 -->
?? <servlet>
????????<servlet-name>DisplayChart</servlet-name>
????????<servlet-class>org.jfree.chart.servlet.DisplayChart</servlet-class>
?</servlet>
?<servlet-mapping>
????????<servlet-name>DisplayChart</servlet-name>
???????? <url-pattern>/DisplayChart</url-pattern>
?</servlet-mapping>
?
?<session-config>
? <session-timeout>1200</session-timeout>
?</session-config>
?<!--<jsp-config>
??<jsp-property-group>
???<url-pattern>*.jsp</url-pattern>
???<trim-directive-whitespaces>true</trim-directive-whitespaces>
??</jsp-property-group>
?</jsp-config>-->
?<welcome-file-list>
? <welcome-file>index.jsp</welcome-file>
?</welcome-file-list>
?<login-config>
? <auth-method>BASIC</auth-method>
?</login-config>
</web-app>

最后,请大家慢慢品味其中差异。

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