用AJAX实现的级联菜单

package com.accp.biz; import java.util.ArrayList; import java.util.List; import com.accp.entity.Country; import com.accp.entity.Province; public class Manager { private static List places=new ArrayList(); static{ Country country=new Country(); places.add(country); country.setName("中国"); List provinces=new ArrayList(); country.setProvinces(provinces); Province p=new Province(); provinces.add(p); p.setName("辽宁"); List citys=new ArrayList(); p.setCitys(citys); citys.add("大连"); citys.add("铁岭"); citys.add("沈阳*"); p=new Province(); p.setName("山东"); provinces.add(p); citys=new ArrayList(); p.setCitys(citys); citys.add("青岛"); citys.add("济南*"); citys.add("泰安"); citys.add("潍坊"); p=new Province(); p.setName("河北"); provinces.add(p); citys=new ArrayList(); p.setCitys(citys); citys.add("石家庄*"); citys.add("保定"); citys.add("秦皇岛"); citys.add("唐山"); //美国 country=new Country(); places.add(country); country.setName("美国"); provinces=new ArrayList(); country.setProvinces(provinces); p=new Province(); p.setName("芝加哥"); provinces.add(p); citys=new ArrayList(); p.setCitys(citys); citys.add("saa*"); citys.add("fa"); p=new Province(); p.setName("华盛顿"); provinces.add(p); p=new Province(); p.setName("纽约"); provinces.add(p); } public String getAllCountry(){ StringBuffer results=new StringBuffer("<results>"); for(int i=0;i<places.size();i++){ Country c=(Country)places.get(i); results.append("<result>"); results.append(c.getName()); results.append("</result>"); } results.append("</results>"); return results.toString(); } //选择国家，返回省列表 public String selectCountry(int cid){ StringBuffer results=new StringBuffer("<results>"); Country c=(Country)places.get(cid); List ps=c.getProvinces(); if(ps==null||ps.isEmpty()){ results.append("</results>"); return results.toString(); } for(int i=0;i<ps.size();i++){ Province p=(Province)ps.get(i); results.append("<result>"); results.append(p.getName()); results.append("</result>"); } results.append("</results>"); return results.toString(); } //选择省，返回市 public String selectProvince(int cid,int pid){ StringBuffer results=new StringBuffer("<results>"); Country c=(Country)places.get(cid); List provinces=c.getProvinces(); Province p=(Province)provinces.get(pid); List citys=p.getCitys(); if(citys==null||citys.isEmpty()){ results.append("</results>"); return results.toString(); } for(int i=0;i<citys.size();i++){ results.append("<result>"); results.append(citys.get(i).toString()); results.append("</result>"); } results.append("</results>"); return results.toString(); } }