<script type="text/javascript" src="${ctx}/components/yunm/yunm.combox.js"></script>
<div class="form-group">
 <div class="row">
 <div class="col-md-6">
 <select name="province_code" class="form-control combox" ref="city_select"
 refUrl="${ctx}/procity?pro_code={value}&city_code=HSLY">
 </select>
 </div>
 <div class="col-md-6">
 <select name="city_code" id="city_select" class="form-control">
 </select>
 </div>
 </div>
</div>
<script type="text/javascript">
<!--
 $(function() {
 if ($.fn.combox) {
 $("select.combox", $p).combox();
 }
 });
//-->
</script>

(function($) {
 var _onchange = function(event) {
 var $ref = $("#" + event.data.ref);
 if ($ref.size() == 0)
 return false;

 var refUrl = event.data.refUrl;
 var value = encodeURIComponent(event.data.$this.val());
 YUNM.debug(value);

 $.ajax({
 type : 'POST',
 dataType : "json",
 url : refUrl.replace("{value}", value),
 cache : false,
 data : {},
 success : function(response) {
 $ref.empty();

 addHtml(response, $ref);
 $ref.trigger("change").combox();
 },
 error : YUNM.ajaxError
 });

 };

 var addHtml = function(response, $this) {
 var json = YUNM.jsonEval(response);
 if (!json)
 return;

 var html = '';
 $.each(json, function(i) {
 if (json[i]) {

 html += '<option value="' + json[i].value + '"';

 if (json[i].selected) {
  html += ' selected="' + json[i].selected;
 }

 html += '">' + json[i].name + '</option>';
 }
 });

 $this.html(html);
 };

 $.extend($.fn, {
 combox : function() {

 return this.each(function(i) {
 var $this = $(this);

 var value = $this.val() || '';
 var ref = $this.attr("ref");

 var refUrl = $this.attr("refUrl") || "";
 if (refUrl) {
  refUrl = refUrl.replace("{value}", encodeURIComponent(value));
 }

 if (refUrl) {
  $.ajax({
  type : 'POST',
  dataType : "json",
  url : refUrl,
  cache : false,
  data : {},
  success : function(response) {
  addHtml(response, $this);

  if (ref && $this.attr("refUrl")) {
  $this.unbind("change", _onchange).bind("change", {
   ref : ref,
   refUrl : $this.attr("refUrl"),
   $this : $this,
  }, _onchange).trigger("change");
  }
  },
  error : YUNM.ajaxError
  });
 }

 });
 }
 });
})(jQuery);

package com.honzh.spring.controller;

import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import com.honzh.biz.database.entity.City;
import com.honzh.biz.database.entity.Option;
import com.honzh.biz.database.entity.Provincial;
import com.honzh.common.util.JsonUtil;
import com.honzh.spring.service.CityService;
import com.honzh.spring.service.ProvincialService;

@Controller
@RequestMapping(value = "/procity")
public class ProcityController extends BaseController {
 private static Logger logger = Logger.getLogger(ProcityController.class);

 /**
 * 当传递city_code，则表明下拉框要被选中，否则不选中
 */
 @RequestMapping("")
 public void index(@RequestParam(value = "city_code", required = false) String city_code,
 @RequestParam(value = "pro_code", required = false) String pro_code, HttpServletResponse response) {
 try {
 logger.debug("获取所在地区" + city_code + ", 省" + pro_code);

 // 如果pro_code为””，则表明要获取城市菜单，否则获取市级菜单
 if (!pro_code.equals("")) {
 Integer pro_id = ProvincialService.getInstance().getByProvincialcode(pro_code).getId();
 List<City> citys = CityService.getInstance().getCitysByProvincialId(pro_id);
 List<Option> coptions = new ArrayList<Option>(citys.size());

 for (City city : citys) {
  Option coption = new Option();
  coption.setId(city.getId());
  coption.setName(city.getCname());
  coption.setValue(city.getCode());

  // 市级菜单被选中
  if (city_code != null && !city_code.equals("")) {
  if (city.getCode().equals(city_code)) {
  coption.setSelected("selected");
  }
  }
  coptions.add(coption);
 }
 renderJson(response, coptions);
 } else {
 List<Provincial> provincials = ProvincialService.getInstance().getProvincials();

 // 转换成标准的option属性（name,value,selected）
 List<Option> options = new ArrayList<Option>(provincials.size());

 // 被选中的省市
 // 则说明是展示页面，此时需要为省级菜单和市级菜单设置选择项
 if (city_code != null && !city_code.equals("")) {
  Provincial selected_provincial = ProvincialService.getInstance().getProvincialByCitycode(city_code);

  pro_code = selected_provincial.getProcode();
 } else {
  pro_code = provincials.get(0) == null ? "" : provincials.get(0).getProcode();
 }

 for (Provincial provincial : provincials) {
  Option option = new Option();
  option.setId(provincial.getId());
  option.setName(provincial.getProname());
  option.setValue(provincial.getProcode());

  if (!pro_code.equals("") && provincial.getProcode().equals(pro_code)) {
  option.setSelected("selected");
  }

  options.add(option);
 }

 renderJson(response, JsonUtil.toJson(options));
 }

 } catch (Exception e) {
 logger.error(e.getMessage());
 logger.error(e.getMessage(), e);

 renderJson(response, null);
 }
 }

}

package com.honzh.spring.service;

import java.util.ArrayList;
import java.util.List;

import com.honzh.biz.database.entity.City;
import com.honzh.biz.database.entity.Provincial;
import com.honzh.biz.database.mapper.ProvincialMapper;
import com.honzh.common.spring.SpringContextHolder;

public class ProvincialService {

 private static Object lock = new Object();
 private static ProvincialService config = null;

 private ProvincialService() {
 provincials = new ArrayList<Provincial>();

 ProvincialMapper mapper = SpringContextHolder.getBean(ProvincialMapper.class);
 provincials.addAll(mapper.getProvincials());
 }

 public static ProvincialService getInstance() {
 synchronized (lock) {
 if (null == config) {
 config = new ProvincialService();
 }
 }
 return (config);
 }

 public Provincial getByProvincialcode(String provincial_code) {
 for (Provincial provincial : provincials) {
 if (provincial.getProcode().equals(provincial_code)) {
 return provincial;
 }
 }
 return null;
 }

 private List<Provincial> provincials = null;

 public List<Provincial> getProvincials() {
 return provincials;
 }

 public Provincial getProvincialByCitycode(String city_code) {
 City city = CityService.getInstance().getCityByCode(city_code);

 for (Provincial provincial : provincials) {
 if (provincial.getId().intValue() == city.getProid().intValue()) {
 return provincial;
 }
 }
 return null;
 }

 public Provincial getProvincialByCode(String province_code) {
 for (Provincial provincial : provincials) {
 if (provincial.getProcode().equals(province_code)) {
 return provincial;
 }
 }
 return null;
 }

}

 /**
 * 如果出错的话，response直接返回404
 */
 protected void renderJson(HttpServletResponse response, Object responseObject) {
 PrintWriter out = null;
 try {
 if (responseObject == null) {
 response.sendError(404);
 return;
 }
 // 将实体对象转换为JSON Object转换
 String responseStr = JsonUtil.toJson(responseObject);
 response.setCharacterEncoding("UTF-8");
 response.setContentType("application/json; charset=utf-8");

 out = response.getWriter();
 out.append(responseStr);

 logger.debug("返回是：" + responseStr);
 } catch (IOException e) {
 logger.error(e.getMessage());
 logger.error(e.getMessage(), e);
 } finally {
 if (out != null) {
 out.close();
 }
 }
 }