merge标签合并标记需要两个或两个以上的列表作为参数，并把它们合并在一起，如下所示：
<s:merge var="myMergedIterator"> <s:param value="%{myList1}" /> <s:param value="%{myList2}" /> <s:param value="%{myList3}" /> </s:merge> <s:iterator value="%{#myMergedIterator}"> <s:property /> </s:iterator>
如果有两个列表A和B的值，A1，A2和B1，B2。合并列表，会给出A1，B1，A2，B2。
创建动作类：
首先，让我们创建一个简单的类叫做Employee.java，它看起来像：
package com.yiibai.struts2; import java.util.ArrayList; import java.util.List; import org.apache.struts2.util.SubsetIteratorFilter.Decider; public class Employee { private String name; private String department; public Employee(){} public Employee(String name,String department) { this.name = name; this.department = department; } private List employees; private List contractors; public String execute() { employees = new ArrayList(); employees.add(new Employee("George","Recruitment")); employees.add(new Employee("Danielle","Accounts")); employees.add(new Employee("Melissa","Recruitment")); employees.add(new Employee("Rose","Accounts")); contractors = new ArrayList(); contractors.add(new Employee("Mindy","Database")); contractors.add(new Employee("Vanessa","Network")); return "success"; } public Decider getRecruitmentDecider() { return new Decider() { public boolean decide(Object element) throws Exception { Employee employee = (Employee)element; return employee.getDepartment().equals("Recruitment"); } }; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getDepartment() { return department; } public void setDepartment(String department) { this.department = department; } public List getEmployees() { return employees; } public void setEmployees(List employees) { this.employees = employees; } public List getContractors() { return contractors; } public void setContractors(List contractors) { this.contractors = contractors; } }
Employee类有两个属性 - name 和 department，我们也有两个员工名单 - employees 和contractors。我们有一个方法叫做getRecruitmentDecider，返回Decider 对象。Decider 实现返回true，如果雇员招聘部门工作，否则返回false。
接下来，让我们创建一个DepartmentComparator 比较Employee对象：
package com.yiibai.struts2; import java.util.Comparator; public class DepartmentComparator implements Comparator { public int compare(Employee e1, Employee e2) { return e1.getDepartment().compareTo(e2.getDepartment()); } @Override public int compare(Object arg0, Object arg1) { return 0; } }
在上面的例子所示，部门比较的基础上按字母顺序排列的部门员工进行比较。
创建视图
创建一个文件叫做employee.jsp以下内容：
<%@ page contentType="text/html; charset=UTF-8"%> <%@ taglib prefix="s" uri="/struts-tags"%> <html> <head> <title>Employees</title> </head> <body> <b>Employees and Contractors Merged together</b> <br /> <s:merge id="allemployees"> <s:param value="employees" /> <s:param value="contractors" /> </s:merge> <s:iterator value="allemployees"> <s:property value="name"/>, <s:property value="department"/><br/> </s:iterator> </body> </html>
合并标记需要两个或两个以上的列表作为参数。我们需要给合并一个id，这样我们就可以重用它。在这个例子中，我们提供了作为参数传递给员工和承包商的合并标签。然后，我们使用“allemployees”ID合并列表遍历并打印员工的细节。
配置文件
struts.xml中应该像这样：
<"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="employee" method="execute"> <result name="success">/employee.jsp</result> </action> </package> </struts>
web.xml中，应该像这样：
<"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>
右键点击项目名称，并单击 Export > WAR File创建一个WAR文件。然后部署此WAR在Tomcat的webapps目录下。最后，启动Tomcat服务器和尝试访问URL http://localhost:8080/HelloWorldStruts2/employee.action。这会给出以下画面：