创建Web应用的配置文件
对于Struts应用，它的配置文件web.xml应该对ActionServlet类进行配置，此外，还应该声明Web应用所使用的Struts标签库，本例中声明使用了三个标签库: Struts Bean、Struts HTML和Struts Logic标签库。例程2-7为web.xml的源代码。
例程2-7 web.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
"http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN"
"http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app>
<display-name>HelloApp Struts Application</display-name>
<!-- Standard Action Servlet Configuration -->
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<load-on-startup>2</load-on-startup>
</servlet>
<display-name>HelloApp Struts Application</display-name>
<!-- Standard Action Servlet Configuration -->
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
</init-param>
<load-on-startup>2</load-on-startup>
</servlet>
<!-- Standard Action Servlet Mapping -->
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>action</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<!-- The Usual Welcome File List -->
<welcome-file-list>
<welcome-file>hello.jsp</welcome-file>
</welcome-file-list>
<welcome-file-list>
<welcome-file>hello.jsp</welcome-file>
</welcome-file-list>
<!-- Struts Tag Library Descriptors -->
<taglib>
<taglib-uri>/WEB-INF/struts-bean.tld</taglib-uri>
<taglib-location>/WEB-INF/struts-bean.tld</taglib-location>
</taglib>
<taglib>
<taglib-uri>/WEB-INF/struts-bean.tld</taglib-uri>
<taglib-location>/WEB-INF/struts-bean.tld</taglib-location>
</taglib>
<taglib>
<taglib-uri>/WEB-INF/struts-html.tld</taglib-uri>
<taglib-location>/WEB-INF/struts-html.tld</taglib-location>
</taglib>
<taglib-uri>/WEB-INF/struts-html.tld</taglib-uri>
<taglib-location>/WEB-INF/struts-html.tld</taglib-location>
</taglib>
<taglib>
<taglib-uri>/WEB-INF/struts-logic.tld</taglib-uri>
<taglib-location>/WEB-INF/struts-logic.tld</taglib-location>
</taglib>
<taglib-uri>/WEB-INF/struts-logic.tld</taglib-uri>
<taglib-location>/WEB-INF/struts-logic.tld</taglib-location>
</taglib>
</web-app>
创建Struts框架的配置文件
正如前面提及的，Struts框架允许把应用划分成多个组件，提高开发速度。而Struts框架的配置文件struts-config.xml可以把这些组件组装起来，决定如何使用它们。例程2-8是helloapp应用的struts-config.xml文件的源代码。
例程2-8 struts-config.xml
<?xml version="1.0" encoding="ISO-8859-1" ?>
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE struts-config PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 1.1//EN"
"http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd">
"-//Apache Software Foundation//DTD Struts Configuration 1.1//EN"
"http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd">
<!--
This is the Struts configuration file for the "Hello!" sample application
-->
This is the Struts configuration file for the "Hello!" sample application
-->
<struts-config>
<!-- ======== Form Bean Definitions =================================== -->
<form-beans>
<form-bean name="HelloForm" type="hello.HelloForm"/>
</form-beans>
<form-beans>
<form-bean name="HelloForm" type="hello.HelloForm"/>
</form-beans>
<!-- ========== Action Mapping Definitions ============================== -->
<action-mappings>
<!-- Say Hello! -->
<action path = "/HelloWorld"
type = "hello.HelloAction"
name = "HelloForm"
scope = "request"
validate = "true"
input = "/hello.jsp"
>
<forward name="SayHello" path="/hello.jsp" />
</action>
</action-mappings>
<action-mappings>
<!-- Say Hello! -->
<action path = "/HelloWorld"
type = "hello.HelloAction"
name = "HelloForm"
scope = "request"
validate = "true"
input = "/hello.jsp"
>
<forward name="SayHello" path="/hello.jsp" />
</action>
</action-mappings>
<!-- ========== Message Resources Definitions =========================== -->
<message-resources parameter="hello.application"/>
<message-resources parameter="hello.application"/>
</struts-config>
以上代码对helloapp应用的HelloForm、HelloAction和消息资源文件进行了配置，首先通过<form-bean>元素配置了一个ActionForm Bean，名叫HelloForm，它对应的类为hello.HelloForm：
<form-bean name="HelloForm" type="hello.HelloForm"/>
接着通过元素配置了一个Action组件：
<action path = "/HelloWorld"
type = "hello.HelloAction"
name = "HelloForm"
scope = "request"
validate = "true"
input = "/hello.jsp"
>
<forward name="SayHello" path="/hello.jsp" />
</action>
type = "hello.HelloAction"
name = "HelloForm"
scope = "request"
validate = "true"
input = "/hello.jsp"
>
<forward name="SayHello" path="/hello.jsp" />
</action>
<action>元素的path属性指定请求访问Action的路径，type属性指定Action的完整类名，name属性指定需要传递给Action的ActionForm Bean，scope属性指定ActionForm Bean的存放范围，validate属性指定是否执行表单验证，input属性指定当表单验证失败时的转发路径。<action>元素还包含一个<forward>子元素，它定义了一个请求转发路径。
本例中的 <action>元素配置了HelloAction组件，对应的类为hello.HelloAction，请求访问路径为"HelloWorld"，当Action类被调用时，Struts框架应该把已经包含表单数据的HelloForm Bean传给它。HelloForm Bean存放在request范围内，并且在调用Action类之前，应该进行表单验证。如果表单验证失败，请求将被转发到接收用户输入的网页hello.jsp，让用户纠正错误。
struts-config.xml文件最后通过元素定义了一个Resource Bundle： <message-resources parameter="hello.application"/>
<message-resources>元素的parameter属性指定Resource Bundle使用的消息资源文件。本例中parameter属性为"hello.application"，表明消息资源文件名为"application.properties"，它的存放路径为WEB-INF/classes/hello/application.properties
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