检查详细示例（Check Detailed Example）10

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2023-12-01

param标签可用于参数化其他标签。 include标记和bean标记是此类标记的示例。让我们在讨论bean标签时采用我们讨论的相同示例。

创建Action类 (Create Action Class)

package cn.xnip.struts2;
public class HelloWorldAction {
   private String name;
   public String execute() throws Exception {
      return "success";
   }
   public String getName() {
      return name;
   }
   public void setName(String name) {
      this.name = name;
   }
}

创建视图 (Create Views)

让我们拥有以下内容的HelloWorld.jsp -

<%@ page contentType = "text/html; charset = UTF-8" %>
<%@ taglib prefix = "s" uri = "/struts-tags" %>
<html>
   <head>
      <title>Hello World</title>
   </head>
   <body>
      <s:bean name = "org.apache.struts2.util.Counter" var = "counter">
         <s:param name = "first" value = "20"/>
         <s:param name = "last" value = "25" />
      </s:bean>
      <ul>
         <s:iterator value = "#counter">
            <li><s:property /></li>
         </s:iterator>
      </ul>
   </body>
</html>

接下来让我们为employees.jsp提供以下内容 -

<%@ page contentType = "text/html; charset = UTF-8"%>
<%@ taglib prefix = "s" uri = "/struts-tags"%>
<html>
   <head>
      <title>Employees</title>
   </head>
   <body>
      <p>An example of the include tag: </p>
      <s:include value = "HelloWorld.jsp"/>
   </body>
</html>

配置文件 (Configuration Files)

你的struts.xml看起来应该像 -

<?xml version = "1.0" Encoding = "UTF-8"?>
<!DOCTYPE struts PUBLIC
   "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
   "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
   <constant name = "struts.devMode" value = "true" />
   <package name = "helloworld" extends = "struts-default">
      <action name = "hello" 
         class = "cn.xnip.struts2.HelloWorldAction" 
         method = "execute">
         <result name = "success">/HelloWorld.jsp</result>
      </action>
      <action name = "employee" 
         class = "cn.xnip.struts2.Employee" 
         method = "execute">
         <result name = "success">/employee.jsp</result>
      </action>
   </package>
</struts>

您的web.xml应该如下所示 -

<?xml version = "1.0" Encoding = "UTF-8"?>
<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_3_0.xsd"
   id = "WebApp_ID" version = "3.0">
   <display-name>Struts 2</display-name>
   <welcome-file-list>
      <welcome-file>index.jsp</welcome-file>
   </welcome-file-list>
   <filter>
      <filter-name>struts2</filter-name>
      <filter-class>
         org.apache.struts2.dispatcher.FilterDispatcher
      </filter-class>
   </filter>
   <filter-mapping>
      <filter-name>struts2</filter-name>
      <url-pattern>/*</url-pattern>
   </filter-mapping>
</web-app>

右键单击项目名称，然后单击“ Export 》 WAR File以创建War文件。然后在Tomcat的webapps目录中部署此WAR。最后，启动Tomcat服务器并尝试访问URL http://localhost:8080/HelloWorldStruts2/hello.action 。这将产生以下屏幕 -

在此示例中，我们将实例化org.apache.struts2.util.Counter bean的新实例。然后我们将第一个属性设置为20，将最后一个属性设置为25.这意味着计数器将具有值20,21,22,23,24和25.我们给bean命名为“counter”。 struts bean标记实例化bean并将其放入值栈。我们现在可以使用迭代器来遍历Counter bean并打印出计数器的值。