Struts2 iterator标签

package com.h3.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.h3.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 有以下内容：

<%@ page contenttype="text/html; charset=utf-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>employees</title>
</head>
<body>
<b>example of iterator tag</b><br/>
<s:iterator value="employees">
	<s:property value="name"/> , 
	<s:property value="department"/><br/>
</s:iterator>
<br/><br/>
<b>employees sorted by department</b><br/>

<s:bean name="com.h3.struts2.departmentcomparator" 
   var="deptcomparator" />

<s:sort comparator="deptcomparator" source="employees">
   <s:iterator>
      <s:property value="name"/> , 
      <s:property value="department"/><br/>
   </s:iterator>
</s:sort>
<br/><br/>
<b>subset tag - employees working in recruitment department </b><br/>
<s:subset decider="recruitmentdecider" source="employees">
   <s:iterator>
      <s:property value="name"/> , 
      <s:property value="department"/><br/>
   </s:iterator>
</s:subset>
<br/><br/>
<b>subset tag - employees 2 and 3 </b><br/>
<s:subset start="1" count="2" source="employees">
   <s:iterator>
      <s:property value="name"/> , 
      <s:property value="department"/><br/>
   </s:iterator>
</s:subset>
</body>
</html>

让我们通过使用一个标签：

iterator标签

我们使用iterator标签要经过员工列表。我们提供“employees”属性iterator标签作为源。在body迭代器标签，我们现在有访问employee对象在员工列表。我们打印随后他们部门的员工的名字。

sort 标签

首先，我们声明一个bean departmentcomparator。我们给这个bean名称deptcomparator。然后，我们使用的形式的标记，并指定作为源和作为比较器使用的的“deptcomparator”的“雇员”列表中。然后，按照前面的例子中，我们遍历列表和打印员工。正如可以看到的输出，打印部门排序的员工列表

subset 标签

用来获取的列表或阵列的一个子集，该子集标记。我们有两种口味的子标签。在第一个例子，我们使用recrutimentdecider 招聘部（请参阅getrecruitmentdecider()方法在employee.java）工作的员工以获取列表。

在第二个例子中，我们没有使用任何决策者，而是我们所追求的元素列表中的第2和第3。子标记需要两个参数“count”和“start”。 “start”的子集确定的起点，“count”的子集确定的长度。

配置文件

struts.xml 应该像这样：

<?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.h3.struts2.employee"
         method="execute">
         <result name="success">/employee.jsp</result>
      </action>
   </package>

</struts>

web.xml中，应该像这样：

<?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：