我搭建的是SSM 框架：
以省市区为例：
我的想法很简单 ，可能想的有点少，首先遍历省份，当数据发生改变调用方法请求根据省的id去查询市区的信息，当市区信息发生改变调用另一个方法去查询县区的信息
1、实体类entity：area
package com.htzn.entity;
public class Area {
private String id ;
private String name;
private String pid;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPid() {
return pid;
}
public void setPid(String pid) {
this.pid = pid;
}
}2、接口层 dao
package com.htzn.dao;
import java.util.List;
import com.htzn.entity.Area;
public interface AreaDao {
//获取省的信息
public List<Area> getProvince();
//获取市区信息
public List<Area> getCity(Integer pid);
//获取所有县区信息
public List<Area> getArea(Integer pid);
}3、接口service层，（个人觉得两个接口层公用一个也行，就像那种公用一个的改为mapper接口层那种的也很方便，可能这样比较不规范吧）
package com.htzn.service;
import java.util.List;
import com.htzn.entity.Area;
public interface AreaService {
public List<Area> getProvince();
public List<Area> getCity(Integer pid);
public List<Area> getArea(Integer pid);
}4、接口实现类serviceImpl
package com.htzn.serviceImpl;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.htzn.dao.AreaDao;
import com.htzn.entity.Area;
import com.htzn.service.AreaService;
@Service
public class AreaServiceImpl implements AreaService {
@Autowired
AreaDao areadao;
@Override
public List<Area> getProvince() {
// TODO Auto-generated method stub
return areadao.getProvince();
}
@Override
public List<Area> getCity(Integer pid) {
// TODO Auto-generated method stub
return areadao.getCity(pid);
}
@Override
public List<Area> getArea(Integer pid) {
// TODO Auto-generated method stub
return areadao.getArea(pid);
}
}5、控制器：contoller
package com.htzn.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import com.htzn.dao.AreaDao;
import com.htzn.entity.Area;
@Controller
public class AreaController {
//自动注入
@Autowired
AreaDao areadao;
//获取省份映射到页面
@RequestMapping("/getpervice")
public String privce(Model model) {
List<Area> list = areadao.getProvince();
model.addAttribute("province", list);
return "arealist";
}
//根据省份id获取对应市区
@ResponseBody
@RequestMapping("/getcity")
public List<Area> city(@RequestParam(value="pid",required=false) Integer id) {
List<Area> city = areadao.getCity(id);
return city;
}
//根据市区id获取相应的县区
@ResponseBody
@RequestMapping("/getarea")
public List<Area> area(@RequestParam(value="pid",required=false) Integer id) {
List<Area> area = areadao.getArea(id);
return area;
}
}6、最后映射页面：jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" isELIgnored="false"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fm"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
</head>
<body>
省：
<select name="province" id="province" onchange="changeCity()">
<c:forEach items="${province }" var="list">
<option value="${list.id }" >${list.name }</option>
</c:forEach>
</select>
市：
<select id="city" name="city" onchange="changeDistrict()">
<option value="">-- 请选择市 --</option>
</select>
区（县）：
<select id="district" name="district" onchange="changehidden()">
<option value="">-- 请选择县(区) --</option>
</select> -->
</body>
<script type="text/javascript">
function changeCity(){
//当省的内容发生变化的时候，响应的改变省的隐藏域的值
$("#phidden").val($("#province option:selected").html());
//页面加载完成，将省的信息加载完成
//下拉列表框标签对象的val()方法就是选中的option标签的value的属性值
var pid = $("#province").val();
alert(pid);
$.ajax({
url:"/sky-ssm/getcity",
type:'post',
data:{"pid":pid},
dataType: "json",
success:function(data){
//清空城市下拉列表框的内容
$("#city").html("<option value=''>-- 请选择市 --</option>");
$("#district").html("<option value=''>-- 请选择区/县 --</option>");
//遍历json，json数组中每一个json，都对应一个省的信息，都应该在省的下拉列表框下面添加一个<option>
for(var i=0;i<data.length;i++){
var $option = $("<option value='"+data[i].id+"'>"+data[i].name+"</option>");
$("#city").append($option);
}
},
error:function(data){
alert("失败了");
}
});
}
function changeDistrict(){
//当城市的内容发生变化的时候，相应的改变城市的隐藏域的值
$("#chidden").val($("#city option:selected").html());
//页面加载完成，将省的信息加载完成
//下拉列表框标签对象的val()方法就是选中的option标签的value的属性值
var pid = $("#city").val();
$.ajax({
url:"/sky-ssm/getarea",
data:{"pid":pid},
dataType:"json",
success:function(data){
//清空城市下拉列表框的内容
$("#district").html("<option value=''>-- 请选择区/县 --</option>");
for(var i=0;i<data.length;i++){
var $option = $("<option value='"+data[i].id+"'>"+data[i].name+"</option>");
$("#district").append($option);
}
}
});
}
function changehidden(){
//当城市的内容发生变化的时候，相应的改变城市的隐藏域的值
$("#dhidden").val($("#district option:selected").html());
}
</script>
</html>7、mapper.xml文件：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.htzn.dao.AreaDao">
<resultMap id="BaseResultMap" type="com.htzn.entity.Area">
<!--
WARNING - @mbg.generated
This element is automatically generated by MyBatis Generator, do not modify.
This element was generated on Thu Jan 09 17:01:48 CST 2020.
-->
<id column="id" jdbcType="VARCHAR" property="id" />
<result column="name" jdbcType="VARCHAR" property="name" />
<result column="pid" jdbcType="VARCHAR" property="pid" />
</resultMap>
<sql id="Base_Column_List">
<!--
WARNING - @mbg.generated
This element is automatically generated by MyBatis Generator, do not modify.
This element was generated on Thu Jan 09 17:01:48 CST 2020.
-->
id, name, pid
</sql>
<select id="getProvince" resultMap="BaseResultMap">
select
<include refid="Base_Column_List" />
from area
where pid = 0
</select>
<select id="getCity" resultMap="BaseResultMap">
select
<include refid="Base_Column_List" />
from area
where pid = #{pid}
</select>
<select id="getArea" resultMap="BaseResultMap">
select
<include refid="Base_Column_List" />
from area
where pid = #{pid}
</select>
<select id="selectByPrimaryKey" parameterType="java.lang.Integer" resultMap="BaseResultMap">
<!--
WARNING - @mbg.generated
This element is automatically generated by MyBatis Generator, do not modify.
This element was generated on Thu Jan 09 17:01:48 CST 2020.
-->
select
<include refid="Base_Column_List" />
from dept
where id = #{id,jdbcType=INTEGER}
</select>
</mapper>因为就是测试可不可行直接写的select下拉框，结果图：
