Struts2 遍历Map,List

最新推荐文章于 2015-12-31 11:57:19 发布

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最新推荐文章于 2015-12-31 11:57:19 发布

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分类专栏： SSH 文章标签： struts2 遍历 map list

本文链接：https://blog.youkuaiyun.com/sunlovefly2012/article/details/14129885

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本文详细介绍了在Struts2框架中如何遍历和使用Map数据结构，包括字符串映射、对象映射、字符串数组映射和列表映射，并通过示例展示了遍历方法。

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package com.sf.demo.action;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.opensymphony.xwork2.ActionSupport;
import com.sf.demo.model.Product;
import com.sf.demo.model.Student;
public class MapAction extends ActionSupport
{
    private Map<String,String> map;
   
	private Map<String,Student> studentMap;
	
	private Map<String,String[]> arrayMap;
	
	private Map<String,List<Student>> listMap;
	
	public String testMap(){
		map=new HashMap<String,String>();
		map.put("1", "one");
		map.put("2", "two");
		
		studentMap=new HashMap<String,Student>();
		studentMap.put("student1",new Student(new Long(1),"20034140201","张三1","男",25));
		studentMap.put("student2",new Student(new Long(2),"20034140202","张三2","女",26));
		studentMap.put("student3",new Student(new Long(3),"20034140202","张三3","男",27));
		
		arrayMap=new HashMap<String,String[]>();
		arrayMap.put("arr1", new String[]{"1","2003401","leejie","male","20"});
		arrayMap.put("arr2", new String[]{"2","2003402","huanglie","male","25"});
		arrayMap.put("arr3", new String[]{"3","2003403","lixiaoning","male","21"});
		
		listMap=new HashMap<String,List<Student>>();
		
		List<Student> list1=new ArrayList<Student>();
		list1.add(new Student(new Long(1),"20034140201","张三1","男",25));
		list1.add(new Student(new Long(2),"20034140202","张三2","男",25));
		list1.add(new Student(new Long(3),"20034140203","张三3","男",25));
		listMap.put("class1", list1);
		
		List<Student> list2=new ArrayList<Student>();
		list2.add(new Student(new Long(1),"20034140301","李四1","男",20));
		list2.add(new Student(new Long(2),"20034140302","李四2","男",21));
		list2.add(new Student(new Long(3),"20034140303","李四3","男",22));
		list2.add(new Student(new Long(4),"20034140304","李四4","男",23));
		listMap.put("class2", list2);
		 
		return SUCCESS;
		
	}
	
	
	public Map<String, String> getMap() {
		return map;
	}
	public void setMap(Map<String, String> map) {
		this.map = map;
	}
	
	public Map<String, Student> getStudentMap() {
		return studentMap;
	}
	public void setStudentMap(Map<String, Student> studentMap) {
		this.studentMap = studentMap;
	}
	public Map<String, String[]> getArrayMap() {
		return arrayMap;
	}
	public void setArrayMap(Map<String, String[]> arrayMap) {
		this.arrayMap = arrayMap;
	}
	public Map<String, List<Student>> getListMap() {
		return listMap;
	}
	public void setListMap(Map<String, List<Student>> listMap) {
		this.listMap = listMap;
	}
	
	
}

test.jsp

<%@ page contentType="text/html;charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title>struts2中的map遍历总结</title>
</head>
<body>
<b>1.map中的value为String字符串</b><br>
<s:iterator value="map" id="column">
<s:property value="#column"/><br>
key: <s:property value="key"/><br>
value:<s:property value="value"/><br>
******************************************<br>
</s:iterator>
<b>2.map中的value为Student对象</b>
<table border="1" width="50%" cellspacing="0" cellpadding="0">
<tr>
<td>key=value</td>
<td>ID</td>
<td>num</td>
<td>name</td>
<td>sex</td>
<td>age</td>
</tr>
<s:iterator value="studentMap" id="column">
<tr>
<td><s:property value="#column"/></td>
<td><s:property value="value.id"/></td>
<td><s:property value="value.num"/></td>
<td><s:property value="value.name"/></td>
<td><s:property value="value.sex"/></td>
<td><s:property value="value.age"/></td>
</tr>
</s:iterator>
</table>
<p>
<b>3.map中的value为String数组</b>
<table border="1" width="50%" cellspacing="0" cellpadding="0">
<tr>
<td>key=value</td>
<td>ID</td>
<td>num</td>
<td>name</td>
<td>sex</td>
<td>age</td>
</tr>
<s:iterator value="arrayMap" id="column">
<tr>
<td><s:property value="#column"/></td>
<td><s:property value="value[0]"/></td>
<td><s:property value="value[1]"/></td>
<td><s:property value="value[2]"/></td>
<td><s:property value="value[3]"/></td>
<td><s:property value="value[4]"/></td>
</tr>
</s:iterator>
</table>
<p>
<b>4.map中的value为list集合</b>
<table border="1" width="50%" cellspacing="0" cellpadding="0">
<tr>
<td>class</td>
<td>ID</td>
<td>num</td>
<td>name</td>
<td>sex</td>
<td>age</td>
</tr>
<s:iterator value="listMap" id="column">
<s:set name="total" value="#column.value.size"/>
<s:iterator value="#column.value" status="s">
<tr>
<s:if test="#s.first"><td rowspan="${total}"><s:property value="#column.key"/></td></s:if>
<td><s:property value="id"/></td>
<td><s:property value="num"/></td>
<td><s:property value="name"/></td>
<td><s:property value="sex"/></td>
<td><s:property value="age"/></td>
</tr>
</s:iterator>
</s:iterator>
</table>
</body>
</html>

struts2的s:iterator 可以遍历 数据栈里面的任何数组，集合等等,以下几个简单的demo： 

s:iterator 标签有3个属性：     value：被迭代的集合     id   ：指定集合里面的元素的id     status 迭代元素的索引

1:jsp页面定义元素写法 数组或list

<s:iterator value="{'1','2','3','4','5'}" id='number'>      

<s:property value='number'/>A

</s:iterator>  

打印结果为: 1A2A3A4A5A

2:索引的用法如果指定了status，每次的迭代数据都有IteratorStatus的实例，它有以下几个方法 

int getCount()返回当前迭代了几个元素; 

int getIndex()返回当前元素索引;

boolean isEven()当然的索引是否偶数;

boolean isFirst()当前是否第一个元素;

boolean isLast()当前是否最后一个元素; 

boolean isOdd()当前元素索引是否奇数;

<s:iterator value="{'a','b','c'}" id='char' status='st'>      

<s:if test="#st.Even">          

现在的索引是奇数为:<s:property value='#st.index'/>     

</s:if>      

当前元素值：<s:property value='char'/> 

</s:iterator>  

3:遍历map value可以直接定义为：

value="#{"1":"a","2":"b"}"  每个元素以都好隔开。元素之间的key和value 冒号隔开 value也可以是数据栈里面的java.util.Map对象遍历写法如下：

<s:iterator value="map" id="id" status="st">       

key : <s:property value='key'/>      

value:<s:property vlaue='value'/> 

</s:iterator>  

当然key 和value 都可以使java 的 Object

3:遍历数据栈.简单的List类， List<Attr>  class Attr{String attrName;String getAttrName(){return "123";}}

<s:iterator value="label" id="id">      

<s:property value="#id.attrName" />  

</s:iterator>  

当然value 还可以写成 value="%{label}" label可以有.操作 label的属性List 可以写成value="%{label.list}" 

相当于：getLabel().getList();

4:遍历2个list； List<AttrName> attrN {color,size,style} List<AttrValue> attrV {red,20,gay} 这2个list的元素是一一对应的，一个attrN对应一个attrV

<s:iterator value="%{attrN }" id="id"   status="status">  

index    is : <s:property value='status.index'/>  

attrName is : <s:property value='id'/> or<s:property value='%{id}'/>  

attrName is : <s:property value='%{attrV[#status.index]}'/> 

</s:iterator>