Bootstrap每天必学之级联下拉菜单_javascript技巧

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 citys = CityService.getInstance().getCitysByProvincialId(pro_id);
 List coptions = new ArrayList(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 provincials = ProvincialService.getInstance().getProvincials();

 // 转换成标准的option属性（name,value,selected）
 List options = new ArrayList(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();

 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 provincials = null;

 public List 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();
 }
 }
 }