簡略解釋Java的Struts框架中merge標簽的應用辦法。本站提示廣大學習愛好者：（簡略解釋Java的Struts框架中merge標簽的應用辦法）文章只能為提供參考，不一定能成為您想要的結果。以下是簡略解釋Java的Struts框架中merge標簽的應用辦法正文
merge標簽歸並標志須要兩個或兩個以上的列表作為參數，並把它們歸並在一路，以下所示：
<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>
假如有兩個列表A和B的值，A1，A2和B1，B2。歸並列表，會給出A1，B1，A2，B2。
創立舉措類：
起首，讓我們創立一個簡略的類叫做Employee.java，它看起來像：
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。我們有一個辦法叫做getRecruitmentDecider，前往Decider 對象。Decider 完成前往true，假如雇員雇用部分任務，不然前往false。
接上去，讓我們創立一個DepartmentComparator 比擬Employee對象：
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;
}
}
在下面的例子所示，部分比擬的基本上按字母次序分列的部分員工停止比擬。
創立視圖
創立一個文件叫做employee.jsp以下內容：
<%@ 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>
歸並標志須要兩個或兩個以上的列表作為參數。我們須要給歸並一個id，如許我們便可以重用它。在這個例子中，我們供給了作為參數傳遞給員工和承包商的歸並標簽。然後，我們應用“allemployees”ID歸並列表遍歷並打印員工的細節。
設置裝備擺設文件
struts.xml中應當像如許：
<?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，應當像如許：
<?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>
右鍵點擊項目稱號，並單擊 Export > WAR File創立一個WAR文件。然後安排此WAR在Tomcat的webapps目次下。最初，啟動Tomcat辦事器和測驗考試拜訪URL http://localhost:8080/HelloWorldStruts2/employee.action。這會給出以下畫面：
