基于mybatis实现省市县三级联动

需求：省市县首先只展示出来省，用户选择省份后，出现对应的市，选择城市后，展示对应的县/区

分析：

1.界面上首先展示出省，可以用监听器初始化数据就获得对应的省份

2.点击省份获得市对应的可以用异步传输即ajax

3.只有当用户选择才会将数据传回后端调用数据，否则不发出申请

初始化数据：InitializeListener

import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

import com.oracle.pojo.Provinces;
import com.oracle.service.ProvincesService;

import jdk.nashorn.internal.ir.RuntimeNode.Request;
@WebListener
public class InitializeListener  implements ServletContextListener{
    @Override
    public void contextInitialized(ServletContextEvent sce) {
        ServletContext servletContext = sce.getServletContext();
        servletContext.setAttribute("root",servletContext.getContextPath());
        servletContext.setAttribute("js",servletContext.getContextPath()+"/js");
        //调用所有的
        ProvincesService ps=new ProvincesService();
        List proList = ps.findAllProvinces();
        //数据保存在servletContext中
        servletContext.setAttribute("proList",proList);
       
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
       
    }
}

index.jsp界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>  











省份：
	请选择省份
	
	${pro.province}
	


城市
请选择城市


县/区
请选择县/区

AddressCityServlet.java

@WebServlet(urlPatterns="/address")
public class AddressServlet extends HttpServlet{

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//获得前端页面的provinceid
		String provinceid = req.getParameter("provinceid");
		//调用方法
		CitiesService cs=new CitiesService();
		List citiesList = cs.findCitiesByProvinceid(provinceid);
		System.out.println("citiesList"+citiesList);
		JSonArray jsonArray=JSONArray.fromObject(citiesList);
		resp.setCharacterEncoding("utf-8");
		PrintWriter out=resp.getWriter();
		out.print(jsonArray);
		out.flush();
		out.close();
	}

AddressCityServlet.java

@WebServlet(urlPatterns="/addressCity")
public class AddressCityServlet extends HttpServlet{

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doGet(req, resp);
	}
	
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//获得城市Id
		String cityid = req.getParameter("cityid");
		//调用方法
		AreasService as=new AreasService();
		List areaList = as.findAreaAllBycityid(cityid);
		System.out.println("areaList"+areaList);
		JSonArray jsonArray = JSONArray.fromObject(areaList);
		//以响应的形式传递给前端页面
        PrintWriter out = resp.getWriter();
        out.println( jsonArray );
        out.flush();
        out.close();
	}
}

service层和mapper层代码就不写啦，是很常见的方法，希望会有所帮助，如果发现错误的地方欢迎指出