Ajax+SpringMVC 二级联动

<div class="form-group">
<label for="orgId" class="col-sm-3 control-label">所属部门</label>
<div class="col-sm-9">
<select class="selectpicker" multiple=""  id="orgId" name="orgId" data-width="100%">
<optgroup label="${organizations[0].orgName}">
<c:forEach var="organization" items="${organizations}" begin="1">
${organization.hierarchy}
<c:if test="${organization.hierarchy == 2}">
</optgroup>
<optgroup label="${organization.orgName}">
</c:if>
<option value="${organization.id}">${organization.orgName}</option>
</c:forEach>
</optgroup>
</select>
</div>
</div>

$(function() {
$("#orgId").change(function() {// 改变组织框的值的时候，执行方法getUser();获取对应用户
getUser();
});

});
function getUser() {
var orgId = $("#orgId").find("option:checked").val();
if (orgId == null || orgId == "") {
return;
}
$.ajax({
type : 'get',
url : 'user/getUserByOrg',
async : false,
data : {
orgId : orgId,
},
success : function(msg) {
alert(msg);
if (msg.length > 0) {
for (i = 0; i < msg.length; i++) {
var responsibleUserId = msg[i].id;
var realName = msg[i].realName;

var $option = $("<option>").attr({
"value" : responsibleUserId
}).text(realName);
$("#responsibleUserId").append($option);
}
} else {
}
}
});
}

// 显示默认的页面
@Override
@RequestMapping
public ModelAndView showDefaultPage(HttpSession session) {
// 获取所有科室。每个节点包含其层次信息
List<Organization> organizations = organizationBiz.getOrgExceptRoot();
ModelAndView mav = new ModelAndView();
mav.addObject("organizations", organizations);
mav.setViewName(defaultPage);
return mav;

}

/**获取组织下的用户*/
@RequestMapping("getUserByOrg")
@ResponseBody
public List<User> getUserByOrg(Integer orgId){
return biz.getUserByOrg(orgId);
}