merge標簽合并標記需要兩個或兩個以上的列表作為參數，并把它們合并在一起，如下所示：
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<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> |
如果有兩個列表A和B的值，A1，A2和B1，B2。合并列表，會給出A1，B1，A2，B2。
創建動作類：
首先，讓我們創建一個簡單的類叫做Employee.java，它看起來像：
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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類有兩個屬性 - name 和 department，我們也有兩個員工名單 - employees 和contractors。我們有一個方法叫做getRecruitmentDecider，返回Decider 對象。Decider 實現返回true，如果雇員招聘部門工作，否則返回false。
接下來，讓我們創建一個DepartmentComparator 比較Employee對象：
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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，部門比較的基礎上按字母順序排列的部門員工進行比較。
創建視圖
創建一個文件叫做employee.jsp以下內容：
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<%@ 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> |
合并標記需要兩個或兩個以上的列表作為參數。我們需要給合并一個id，這樣我們就可以重用它。在這個例子中，我們提供了作為參數傳遞給員工和承包商的合并標簽。然后，我們使用“allemployees”ID合并列表遍歷并打印員工的細節。
配置文件
struts.xml中應該像這樣：
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<?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="employee" class="com.yiibai.struts2.Employee" method="execute"> <result name="success">/employee.jsp</result> </action> </package></struts> |
web.xml中，應該像這樣：
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<?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> |
右鍵點擊項目名稱，并單擊 Export > WAR File創建一個WAR文件。然后部署此WAR在Tomcat的webapps目錄下。最后，啟動Tomcat服務器和嘗試訪問URL http://localhost:8080/HelloWorldStruts2/employee.action。這會給出以下畫面：
