struts2 遍历Map的N中方法

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struts2 遍历Map的N中方法

主要针对以下几种情况的Map:
private Map<String, String> strMap = new HashMap<String, String>();
private Map<String, Person> perMap = new HashMap<String, Person>();

private Map<String, String[]> strArryMap = new HashMap<String, String[]>();
private Map<String, List<Person>> perLstMap = new HashMap<String, List<Person>>();

下面给出一个示例
1).ExpressMapAction.java
package com.expre.struts2.action;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.expre.struts2.bean.Person;
import com.expre.struts2.bean.Phone;
import com.opensymphony.xwork2.ActionSupport;

public class ExpressMapAction extends ActionSupport {
private static final long serialVersionUID = -4251480679223607716L;

private Map<String, String> strMap = new HashMap<String, String>();

private Map<String, Person> perMap = new HashMap<String, Person>();

private Map<String, String[]> strArryMap = new HashMap<String, String[]>();

private Map<String, List<Person>> perLstMap = new HashMap<String, List<Person>>();

//get&set方法,这里都省略了
...................

@Override
public String execute() throws Exception {

  // 值为字符串
  strMap.put("first", "zxx");
  strMap.put("second", "lsx");
  strMap.put("third", "wxh");

  // 值为javabean对象
  Person person = new Person("001", "zxx", 22);
  person.setPhone(new Phone("apple", 18957157189L));

perMap.put("one", person);

  person = new Person("002", "lsx", 25);
  person.setPhone(new Phone("HTC", 18957157187L));
  perMap.put("two", person);

  // 数组处理
  strArryMap.put("arr1", new String[] { "1", "310000", "hz" });
  strArryMap.put("arr2", new String[] { "2", "310001", "xh" });
  strArryMap.put("arr3", new String[] { "3", "310002", "sc" });

  //list对象处理
  List<Person> list=new ArrayList<Person>();
  list.add(new Person("001", "zxx", 22));
  list.add(new Person("002", "lsx", 25));
  perLstMap.put("one", list);

  list=new ArrayList<Person>();
  list.add(new Person("003", "wlx", 26));
  list.add(new Person("004", "hzx", 28));
  perLstMap.put("two", list);

return "result";
}
}

2).struts.xml
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<package name="express" extends="struts-default" namespace="/exp">
  <action name="expressMap" class="com.expre.struts2.action.ExpressMapAction">
   <result name="result">/jsp/strMap.jsp</result>
  </action>
</package>
</struts>

3.web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<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>

<welcome-file-list>
<welcome-file>/first.jsp</welcome-file>
</welcome-file-list>
</web-app>

4).strMap.jsp
<%@ page language="java" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
<body>
  <ul>
   <li>访问Map:<s:property value="strMap"/></li>
   <li>访问Map中某个元素:
    <s:property value="strMap.first"/> |
    <s:property value="strMap['second']"/> |
    <s:property value="strMap[\'third\']"/>
   </li>
   <li>访问Map中所有的key:<s:property value="strMap.keys"/></li>
   <li>访问Map中所有的value:<s:property value="strMap.values"/></li>
   <li>访问容器的大小：
    <s:property value="strMap.size()"/> |
    <s:property value="strMap.size"/>//这是map特别的地方
    </li>

    <li>迭代循环取值,最简单
     <s:iterator value="strMap" id="entry">
      <s:property value="#entry"/>{
      key: <s:property value="key"/>
      value:<s:property value="value"/>}|
       </s:iterator>
      </li>

    <li>迭代循环取值
     <s:iterator value="strMap.keySet()" id="key">
      <s:property value="key"/>或<s:property value="#key"/>:
           <s:if test="strMap[#key]!=null">
          <s:property value="strMap.get(#key)"/> |
           </s:if>
       </s:iterator>
      </li>

      <li>迭代循环取数组值
     <s:iterator value="strMap" id="entry">
      <s:property value="#entry"/>{
      <s:property value="value[0]"/>
      <s:property value="value[1]"/> |
      <s:property value="value[2]"/> }
       </s:iterator>
      </li>

      <li>迭代循环取对象值,最直接:
     <ul>
       <s:iterator value="perMap" id="entry">
       <li>
          <s:property value="#entry"/> {
         ID：<s:property value="value.ID"/>
         Name：<s:property value="value.name"/>
         Age：<s:property value="value.age"/> }|
         </li>
       </s:iterator>
       </ul>
      </li>

      <li>迭代循环取对象的属性值
    <s:iterator value="perMap.keySet()" id="key">
          <s:property value="#key"/>:
           <s:iterator value="perMap.get(#key)">
               <s:property value="ID"/>
               <s:property value="name"/>
               <s:property value="phone.name"/>
           </s:iterator>|
      </s:iterator>
      </li>

      <li>稍复杂的迭代
       <s:iterator value="perLstMap" id="entry">
        <s:set name="total" value="#entry.value.size"/>
        <s:iterator value="#entry.value" status="s">
           <s:if test="#s.first">
           <s:property value="#entry.key"/>:共${total}条
           </s:if>   {
           <s:property value="ID"/> |
           <s:property value="name"/>   |
           <s:property value="age"/>
            };
        </s:iterator>
     </s:iterator>
   </li>
   </ul>
</body>
</html>

5).通过url：http://localhost:8080/struts2Jsp/exp/expressMap.action访问就会看到输出！

别的不多说，strMap.jsp已经把使用方法都写出来了！