二级下拉框

jsp

 <select id="AreaValues" onchange="AreaTypeChange()" style="width:100px;">
                <option value="-1">--</option>
               </select>
            <select id="TypeValues">
            <option value="-1">--</option>
            </select>

jquery代码

function AreaType() {
	$.getJSON("/locationsearch/LocationAreaAction.htm", AreaJson);
}

function AreaJson(json) {
	var data = (json.areavalues);
	for ( var theater in data) {
		var option = document.createElement("option");
		document.getElementById("AreaValues").appendChild(option);
		option.value = data[theater].areaseq;
		option.text = data[theater].areacode;

	}
}

function AreaTypeChange() {
	$("#TypeValues").children().remove();
	var areaseq = $("#AreaValues").find("option:selected").val();
	$.getJSON("/locationsearch/LocationTypeAction.htm",
			"twmsLocation.areaseq=" + areaseq, TypeJson);
}
function TypeJson(json) {
	var data = (json.typevalues);
	for ( var theater in data) {
		var option = document.createElement("option");
		document.getElementById("TypeValues").appendChild(option);
		option.value = data[theater].typeseq;
		option.text = data[theater].typecode;

	}
}

$(document).ready(function() {
	AreaType();

});

struts2配置

<!--locationaction对应的action文件   -->
<package name="locationsearch" extends="json-default" namespace="/locationsearch">
		<action name="LocationAreaAction" class="locationaction" method="AreaValues">
			<result type="json"/>
		</action>
		<action name="LocationTypeAction" class="locationaction" method="TypeValues">
			<result type="json"/>
		</action>
	</package>

java代码

	public void AreaValues()throws Exception {
		List<TwmsLocation> areavalues=null ;//查询获得结果
		
		JSONObject jsonobject = new JSONObject();
		JSONArray jsonarray = JSONArray.fromObject(areavalues);
		jsonobject.put("areavalues", jsonarray);
		Struts2Utils.renderJson(jsonobject.toString());
	}
	
	public void TypeValues()throws Exception {
		
		List<TwmsLocation> typevalues=null; //按照传递过来的areaseq查询出结果
		
		JSONObject jsonobject = new JSONObject();
		JSONArray jsonarray = JSONArray.fromObject(typevalues);
		jsonobject.put("typevalues", jsonarray);
		Struts2Utils.renderJson(jsonobject.toString());
	}

javabean文件

public class TwmsLocation extends BaseObject {

	private long areaseq;
	private String areacode;

	private long typeseq;
	private String typecode;

}
public long getAreaseq() {
		return areaseq;
	}

	public void setAreaseq(long areaseq) {
		this.areaseq = areaseq;
	}

	public String getAreacode() {
		return areacode;
	}

	public void setAreacode(String areacode) {
		this.areacode = areacode;
	}

	public long getTypeseq() {
		return typeseq;
	}

	public void setTypeseq(long typeseq) {
		this.typeseq = typeseq;
	}

	public String getTypecode() {
		return typecode;
	}

	public void setTypecode(String typecode) {
		this.typecode = typecode;
	}