struts2中拦截器defaultStack的使用

[ogiso_pest]

前台如下图

如果我在sector中做了选择，则onchange="loadDivisions()，然后使用ajax通信，告诉action当前sector的选项，而action则根据sector的选项值，返回相应的division值。
我在js里的回调函数，写了测试语句;alert("here");alert("Receive:"+data)
但是并没有执行alert，请问是怎么回事啊？是拦截器的问题么？
在action里，我也简单写了测试
this.getResponse().getWriter().print("Action say");
谢谢啦~

loadDivisions()内容如下：

function loadDivisions() {
				var selectedValue;
				var options = document.getElementById("sectorId").options;
				for ( var i = 0; i < options.length; i++) {
					if (options[i].selected == true)
						selectedValue = options[i].value;
				}
				
				if (selectedValue=="100") {
					document.getElementById("companyId").options.length = 0;
				}else{
					var params = {
						"parentSectorId" : selectedValue
					};
					var url = "getSubDivision";
					document.getElementById("divisionId").options.length = 0;
					alert("selectedValue:"+selectedValue);
					$.getJSON(url, params, function callback(data) {
						
						alert("here");
						alert("Receive:"+data);
						option = document.createElement('option');
						option.text= "";
						option.value = 100;
						document.getElementById("divisionId").add(option, 0);
						
						for ( var i = 0; i < data.length; i++) {
							option = document.createElement("option");
							option.text = data[i].name;
							option.value = data[i].id;
							alert("optione:"+option.text+"_"+option.value);
							var divPosition = document.getElementById("divisionId").options.length;
							document.getElementById("divisionId").add(option, divPosition);
						}
					});
				}
			}

如果做了一个非空选择，则根据当前选择，改变Division的选项。
在struts.xml里getSubDivision配置如下

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">

<struts>

    <constant name="struts.enable.DynamicMethodInvocation" value="false" />
    <constant name="struts.devMode" value="false" />

    <package name="default" namespace="/" extends="struts-default">
	
       <action name="toReport" class="action.ReportAction"
			method="toReport">
			<result name="success">/report.jsp</result>
		</action>
		<action name="getSubDivision" class="action.ReportAction"
			method="getSubDivision">
			<interceptor-ref name="defaultStack" />
		</action>
    </package>

</struts>

而ReportAction如下

package action;

import java.io.IOException;
import java.util.List;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.interceptor.ServletResponseAware;
import com.opensymphony.xwork2.ActionSupport;
import dao.DB;
import model.Organization;

public class ReportAction extends ActionSupport implements ServletResponseAware{

	private List<Organization> sectors;
	private List<Organization> divisions;
	private String parentSectorId;
	private HttpServletResponse response;
	
	public String toReport() {
		
		sectors = DB.getAllSectors();
		System.out.println("secots:"+sectors);
		return SUCCESS;
	}
	
	public String getSubDivision() {
		
		if (parentSectorId == "") {
			return null;
		}
		
		int secId = Integer.parseInt(parentSectorId);
		divisions = DB.getDivisionsBySecId(secId);
		System.out.println("SectorId "+ secId +"'s divisions:");
		String str = "";
		for(Organization div: divisions) {
			str += div.getId()+":"+div.getName();
		}
		try {
			this.getResponse().getWriter().print("Action say");
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return ERROR;
		}
		return null;
	}
	
	public List<Organization> getSectors() {
		return sectors;
	}
	
	public void setSectors(List<Organization> sectors) {
		this.sectors = sectors;
	}
	
	public List<Organization> getDivisions() {
		return divisions;
	}
	
	public void setDivisions(List<Organization> divisions) {
		this.divisions = divisions;
	}

	public String getParentSectorId() {
		return parentSectorId;
	}

	public void setParentSectorId(String parentSectorId) {
		this.parentSectorId = parentSectorId;
	}

	public HttpServletResponse getResponse() {
		return response;
	}

	@Override
	public void setServletResponse(HttpServletResponse response) {
		// TODO Auto-generated method stub
		this.response = response;
	}

	
}

[ogiso_pest]

谁能解决啊~
很着急啊！