Ajax实现省市县三级联动代码示例

本篇文章小编给大家分享一下Ajax实现省市县三级联动代码示例，文章代码介绍的很详细，小编觉得挺不错的，现在分享给大家供大家参考，有需要的小伙伴们可以来看看。

首先建立数据库，如下所示

接口

省

import java.util.List;
public interface ProvinceDao {
 List findAll();
}

市

import java.util.List;
public interface CityDao {
 List findCityByPid(int pid);
}

县

import java.util.List;
public interface AreaDao {
 List findAreaByCid(int cid);
}

接口实现类

省

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class ProvinceDaoImpl implements ProvinceDao{
 public List findAll(){
 Connection conn = DBHelper.getConn();
 ArrayList provinces = new ArrayList();
 String sql = "select * from aprovince";
 try {
 PreparedStatement ps = conn.prepareStatement(sql);
 ResultSet rs = ps.executeQuery();
 while (rs.next()){
 Province p = new Province();
 p.setPid(rs.getInt(1));
 p.setPname(rs.getString(2));
 provinces.add(p);
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 return provinces;
 }
}

市

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class CityDaoImpl implements CityDao {
 @Override
 public List findCityByPid(int pid) {
 Connection conn = DBHelper.getConn();

 ArrayList cities = new ArrayList<>();

 String sql = "select * from acity where pid=?";

 try {
 PreparedStatement ps = conn.prepareStatement(sql);
 ps.setInt(1,pid);
 ResultSet rs = ps.executeQuery();
 while (rs.next()){
 City city = new City();
 city.setPid(rs.getInt(3));
 city.setCid(rs.getInt(1));
 city.setCname(rs.getString(2));
 cities.add(city);
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 return cities;
 }
}

县

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class AreaDaoImpl implements AreaDao {
 @Override
 public List findAreaByCid(int cid) {
 Connection conn = DBHelper.getConn();
 ArrayList areas = new ArrayList<>();
 String sql = "select * from aarea where cid=?";

 try {
 PreparedStatement ps = conn.prepareStatement(sql);
 ps.setInt(1,cid);
 ResultSet rs = ps.executeQuery();
 while (rs.next()){
 Area area = new Area();
 area.setCid(rs.getInt(3));
 area.setAid(rs.getInt(1));
 area.setAname(rs.getString(2));
 areas.add(area);
 }
 } catch (SQLException e) {
 e.printStackTrace();
 }
 return areas;
 }
}

servlet

省

package cn.zhc.servlet;

import cn.zhc.dao.Impl.ProvinceDaoImpl;
import cn.zhc.dao.ProvinceDao;
import cn.zhc.domin.Province;
import com.alibaba.fastjson.JSONObject;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@WebServlet("/findAll")
public class FindAll extends HttpServlet {
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 request.setCharacterEncoding("utf-8");
 response.setContentType("text/html;charset=utf-8");

 ProvinceDao provinceDao = new ProvinceDaoImpl();
 List lists=provinceDao.findAll();

 response.getWriter().write(JSONObject.toJSONString(lists));
 }
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 this.doPost(request, response);
 }
}

市

package cn.zhc.servlet;

import cn.zhc.dao.CityDao;
import cn.zhc.dao.Impl.CityDaoImpl;
import cn.zhc.domin.City;
import com.alibaba.fastjson.JSONObject;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@WebServlet("/findCityByPid")
public class FindCityByPid extends HttpServlet {
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 request.setCharacterEncoding("utf-8");
 response.setContentType("text/html;charset=utf-8");

 String pid = request.getParameter("pid");

 CityDao cityDao = new CityDaoImpl();
 List cityList = cityDao.findCityByPid(Integer.parseInt(pid));

 response.getWriter().write(JSONObject.toJSONString(cityList));
 }

 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 this.doPost(request, response);
 }
}

县

package cn.zhc.servlet;

import cn.zhc.dao.AreaDao;
import cn.zhc.dao.Impl.AreaDaoImpl;
import cn.zhc.domin.Area;
import com.alibaba.fastjson.JSONObject;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@WebServlet("/findAreaByCid")
public class FindAreaByCid extends HttpServlet {
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 request.setCharacterEncoding("utf-8");
 response.setContentType("text/html;charset=utf-8");

 String cid = request.getParameter("cid");

 AreaDao areaDao = new AreaDaoImpl();
 List areas = areaDao.findAreaByCid(Integer.parseInt(cid));

 response.getWriter().write(JSONObject.toJSONString(areas));
 }

 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 this.doPost(request, response);
 }
}

JSP页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>


 
 




 请选择
省

 请选择
市

 请选择
县

实现结果如下：