Ajax实现省市县三级联动

本文实例为大家分享了Ajax实现省市县三级联动的具体代码，供大家参考，具体内容如下

首先建立数据库，如下所示

接口

省

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

市

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

县

import java.util.List;
public interface AreaDao {
List<Area> 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<Province> findAll(){
Connection conn = DBHelper.getConn();
ArrayList<Province> provinces = new ArrayList<Province>();
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<City> findCityByPid(int pid) {
Connection conn = DBHelper.getConn();

ArrayList<City> 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<Area> findAreaByCid(int cid) {
Connection conn = DBHelper.getConn();
ArrayList<Area> 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<Province> 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;

@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<City> 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;

@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<Area> 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\” %>
<html>
<head>
<title>三级联动</title>
<script type=\”text/javascript\” src=\”js/jquery-1.8.3.js\”></script>
</head>
<body>
<script type=\”text/javascript\”>
$(function () {
$.ajax({
type:\”get\”,
url:\”findAll\”,
dataType:\”json\”,
success:function (data) {
var obj=$(\”#province\”);
for(var i=0;i<data.length;i++){
var ob=\”<option value=\’\”+data[i].pid+\”\’>\”+data[i].pname+\”</option>\”;
obj.append(ob);
}
}
})

$(\”#province\”).change(function () {
$(\”#city option\”).remove();
$.ajax({
type:\”get\”,
async:false,
url:\”findCityByPid?pid=\”+$(\”#province\”).val(),
dataType:\”json\”,
success:function (data) {
var obj=$(\”#city\”);
for(var i=0;i<data.length;i++){
var ob=\”<option value=\’\”+data[i].cid+\”\’>\”+data[i].cname+\”</option>\”;
obj.append(ob);
}
}
})
});

$(\”#city,#province\”).change(function () {
$(\”#area option\”).remove();
$.ajax({
type:\”get\”,
async:false,
url:\”findAreaByCid?cid=\”+$(\”#city\”).val(),
dataType:\”json\”,
success:function (data) {
var obj=$(\”#area\”);
for(var i=0;i<data.length;i++){
var ob=\”<option value=\’\”+data[i].aid+\”\’>\”+data[i].aname+\”</option>\”;
obj.append(ob);
}
}
})
});
});
</script>
<select name=\”province\” id=\”province\”>
<option value=\”0\”>请选择</option>
</select>省
<select name=\”city\” id=\”city\”>
<option value=\”0\”>请选择</option>
</select>市
<select name=\”area\” id=\”area\”>
<option value=\”0\”>请选择</option>
</select>县
</body>
</html>