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); 

 <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>  

<action name="updateCampaign" class="campaignAction" method="updateCampaign">      <result name="success" type="redirectAction">          <param name="actionName">viewCampaignDetail</param>          <param name="campaignId">${campaignId}</param>      </result>  </action>  

publicclass A {    private String param[];    public String[] getParam() {       returnparam;    }    publicvoid setParam(String[] param) {       this.param = param;    }    publicvoid execute(){       for(int i=0;i<this.param.length;i++){           System.out.println(this.param[i]);       }    }}