struts2 ajax json 实现下拉框

以下是java代码 ：AjaxJsonsj.java

package com.sj.json;
import java.util.ArrayList;
import java.util.List;
import net.sf.json.JSONArray;
import com.opensymphony.xwork2.ActionSupport;
import com.opensymphony.xwork2.Preparable;
import com.sj.pojo.Memberlevel1;
import com.sj.service.MemberLevelService;
@SuppressWarnings({"serial","unchecked"})
public class AjaxJsonsj extends ActionSupport implements Preparable{
	
	private MemberLevelService memberLevelService; // 采用spring注入的service
	private JSONArray result;  // 返回的结果传到前台去
	
	//清除显示多重显示方法
	public void prepare() throws Exception {
		clearErrorsAndMessages();
	}
	
	
	/**
	 * action默认的方法被调用
	 * @author su_jian
	 */
	public String execute(){
		try {
			List list= memberLevelService.browseMemberLevel2();
			// list是具有”键值对“的list 和map类似一个，两个属性
			List listsj = new ArrayList();
			JSONArray jsonArray = new JSONArray();  //json的数组
			Memberlevel1 Memberlevel2 =new Memberlevel1();
			listsj.add(Memberlevel2); 
			for (int i = 0; i <list.size() ; i++) {
				Memberlevel1 memberlevel1 =new Memberlevel1();
				Object[] obj = (Object[]) list.get(i);
				memberlevel1.setIdsj(obj[0]!=null?Integer.valueOf(obj[0].toString()):0);
				memberlevel1.setLevelName(obj[1]!=null?obj[1].toString():"");
				listsj.add(memberlevel1);
			}  //讲list 属性从object 转换成 属性
			jsonArray = JSONArray.fromObject(listsj); //把list方法换成json 对象
			this.result = jsonArray; //付给返回去的值
			System.out.println(this.result);
		} catch (Exception e) {
		  e.printStackTrace();
		}
		return SUCCESS;
	}
	
	
	//以下 是set get 方法
	public MemberLevelService getMemberLevelService() {
		return memberLevelService;
	}
	public void setMemberLevelService(MemberLevelService memberLevelService) {
		this.memberLevelService = memberLevelService;
	}
	public JSONArray getResult() {
		return result;
	}
	public void setResult(JSONArray result) {
		this.result = result;
	}
}

ajax js 代码如下：

	// 返回函数的数据集采用ajax json struts2	
	function showesay(dataResponse) {
		var data = eval('(' + dataResponse.responseText + ')');
		for(var i=0;i<data.length;i++){
					  	var op= document.createElement("option");
					  	var xl = document.getElementById('xl');
					  	op.text = data[i].levelName;
				 		op.value = data[i].idsj;
				 		xl.add(op);
			 }
			 selectMem();
	}
	
	// 返回去的时候重新选择刚才选择的
	function selectMem(){
		with(document.forms(0)){
	    	var len = xl.options.length;
	    	for(var i=0; i<len; i++){
		      if(xl.options[i].text==levelNamesj.value){
		    			xl.options[i].selected = true;
		     }
		    }
		}
	}
	
	
	//获取简单的json数据
	function getjson() {
		var url = 'ajax/ajaxJsonsj.action';
		var pars = '';
		var ajax = new Ajax.Request(url, {
			method :'post',
			parameters :pars,
			onComplete :showesay
		});
	}

struts2 配置文件 struts.xml 如下：

<!-- ajax  json  配置 -->
	<package name="ajax" extends="json-default" namespace="/admin">
			<action name="ajaxJsonsj" class="ajaxJsonsj">
				<result type="json">
				<param name="root">result</param>
				</result>
			</action>
	</package>

jsp 页面代码

<tr class="tr">
  						<th class="center">会员级别</th>
  					<td colspan="3">
  						<SELECT id="xl" name="xl" >
  							
  						</SELECT>
  					</td>
  				
  				</tr>

如愿的现实下拉列表