struts2标签 遍历map集合

首先我们来构造几个map集合。
 
 假设如下代码 都是在ssh配置环境下搭建好，(至少struts2开发环境搭建好)
 
(1).java 代码  
 
     下面的student对象包含的字段为
 
     private Long id;
     private String num;
     private String name;
     private String sex;
     private Integer age;
      Action中的代码
 
           private Map<String,String> map; 
           private Map<String,Student> studentMap; 
           private Map<String,String[]> arrayMap; 
           private Map<String,List<Student>> listMap;   // 实现 四个map对象的get 和set方法。
 
 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); 
 
(2).通过上述java代码我们已经构建好了4个map集合。 接下来的重头戏就是如何通过strut2的标签来获取map集合中的值。
 
<b>1.map中的value为String字符串</b><br>    
 
<s:iterator value="map" id="column">    
<s:property value="#column"/><br>      //这里获取到的值为key=value    即：键值对
key: <s:property value="key"/><br>      //这里的key为内置的，我们只要在value中写上key 即会有值
value:<s:property value="value"/><br>    //同样这里的value也为内置的
</s:iterator>    
 
 <b>2.map中的value为Student对象</b>    
  <s:iterator value="studentMap" id="column">    
  <tr>    
   <td><s:property value="#column"/></td>    
   <td><s:property value="key"/></td>   
   <td><s:property value="value"/></td>   //这里的value返回的是一个student对象
   <td><s:property value="value.id"/></td>    //这里获取student对象中的属性值
   <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>    
 
遍历studentMap 还可以用下面方式，跟上面方式效果是一样的
 
<b>2.map中的value为Student对象</b>    
  <s:iterator value="studentMap" id="column">    
  <tr>    
   <td><s:property value="#column"/></td>    
   <td><s:property value="key"/></td>   
   <s:iterator value="value">
   <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>    
    </s:iterator>
  </tr>    
  </s:iterator>  
 
 
  
  
  <b>3.map中的value为String数组</b>    
 <s:iterator value="arrayMap" id="column">    
   <tr>    
    <td><s:property value="#column"/></td>  <!--同时取出键和值-->
    <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>   
   
     <b>4.map中的value为list集合</b>    
      <s:iterator value="listMap" id="column">    
    <s:set name="total" value="#column.value.size"/>    //注意<s:set 标签的用法
    <s:iterator value="#column.value" status="s">     //这里#column.value 还是一个student的list集合，因而需要再次迭代一次
     <tr>    
     <s:property value="#s.first"/>     //判断是不是集合中的第一个对象
       <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>   
转自：http://www.2cto.com/kf/201310/252442.html