Java+ajax无刷新实现省市县三级联动

package servlet; import java.io.IOException; import java.io.PrintWriter; import java.util.ArrayList; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import dao.AreaDao; import dao.CityDao; import net.sf.json.JSONArray; import net.sf.json.JSONObject; public class LinkageServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); response.setContentType("text/html;charset=utf-8"); PrintWriter out=response.getWriter(); String link=request.getParameter("action"); JSONObject jsonb=JSONObject.fromObject(link); String action=jsonb.get("action").toString(); String father=jsonb.get("id").toString(); System.out.println(action); ArrayList ar=null; if(action.equals("province")){ CityDao city=new CityDao(); ar=city.getCSelectFather(father); } else if(action.equals("city")) { AreaDao are=new AreaDao(); ar=are.getASelectFather(father); } JSONArray arr=JSONArray.fromObject(ar); out.print(action+"="+arr.toString()); out.flush(); out.close(); } /** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request the request send by the client to the server * @param response the response send by the server to the client * @throws ServletException if an error occurred * @throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }