s:iterator usage and examples
s: Iterator attribute introduction
*IneratorStatus object introduction:
This type of object encapsulates the relevant information of this cycle, which is obtained by accessing its attributes. The main attributes are:
Index: The current loop to Index of the collection
Count: The number of times it has been cycled
First: Whether it is the first cycle
Last: Whether it is the last cycle
odd: Whether the current position is an odd number
Even: whether the current position is an even number
eg:
Create a new class Action1.java, the code is as follows:
package my.test;
import com.opensymphony.xwork2.ActionSupport;
public class Action1 extends ActionSupport{
private String[] arr=new String[5];
//一定要添加get/set方法，否则会出现空指针异常
public String[] getArr() {
return arr;
}
public void setArr(String[] arr) {
this.arr = arr;
}
public String execute(){
int i=101;
//下面的for循环的赋值不起作用
for(String a:arr){
a=""+i++;
}
arr[3]="this is 3";//这里验证上面的for循环对arr的赋值是不起作用的，这里由String数组和String的特性来决定，看运行结果即可
return SUCCESS;
}
}Create a new jsp file/iterator.jsp, remember to introduce the Struts tag
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<s:debug></s:debug>
<s:iterator var="one" value="arr" begin="2" status="sta">
<!-- 由于循环到的值保存到值栈中，所以下面通过s:property标签取值 -->
循环到的值为：<s:property value="one"/><br>
循环的次数为：<s:property value="#sta.count"/><br>
循环的索引为：<s:property value="#sta.index"/><br>
是否为奇数：<s:property value="#sta.odd"/><hr>
</s:iterator>
</body>
</html>The last configuration file is:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<constant name="struts.devMode" value="true" />
<package name="test" namespace="/" extends="struts-default">
<action name="iterator" class="my.test.Action1">
<result>/iterator.jsp</result>
</action>
<action name="index">
<result type="redirectAction">
<param name="actionName">HelloWorld</param>
<param name="namespace">/example</param>
</result>
</action>
</package>
<!-- Add packages here -->
</struts>The author is using Struts2 version 2.3.30 , the configuration files of different versions are different.
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