需要的jar包：
数据库代码：
create database school character set utf8; use school; CREATE table provice ( pid INT PRIMARY KEY auto_increment, pname varchar(20) ); INSERT into provice VALUES (null,"河南省"); INSERT into provice VALUES (null,"山东省"); INSERT into provice VALUES (null,"河北省"); CREATE table city ( cid INT PRIMARY KEY auto_increment, cname varchar(20), pid int ); -- 河南省 INSERT into city VALUES (null,"郑州市",1); INSERT into city VALUES (null,"开封市",1); INSERT into city VALUES (null,"洛阳市",1); -- 山东 INSERT into city VALUES (null,"济南市",2); INSERT into city VALUES (null,"青岛市",2); INSERT into city VALUES (null,"淄博市",2); -- 河北 INSERT into city VALUES (null,"石家庄市",3); INSERT into city VALUES (null,"唐山市",3); INSERT into city VALUES (null,"秦皇岛市",3); CREATE table street ( sid INT PRIMARY KEY auto_increment, sname varchar(20), cid int ); -- 郑州市 INSERT into street VALUES (null,"中原区",1); INSERT into street VALUES (null,"二七区",1); INSERT into street VALUES (null,"管城回族区",1); -- 开封市 INSERT into street VALUES (null,"龙亭区",2); INSERT into street VALUES (null,"顺河回族区",2); INSERT into street VALUES (null,"鼓楼区",2); -- 洛阳市 INSERT into street VALUES (null,"汝阳",3); INSERT into street VALUES (null,"宜阳",3); INSERT into street VALUES (null,"洛宁",3); -- 济南市 INSERT into street VALUES (null,"商河县",4); INSERT into street VALUES (null,"济阳县",4); INSERT into street VALUES (null,"平阴县",4); -- 青岛市 INSERT into street VALUES (null,"七区五市",5); INSERT into street VALUES (null,"市南区",5); INSERT into street VALUES (null,"市北区",5); -- 淄博市 INSERT into street VALUES (null,"博山",6); INSERT into street VALUES (null,"周村",6); INSERT into street VALUES (null,"临淄",6); -- 石家庄市 INSERT into street VALUES (null,"正定县",7); INSERT into street VALUES (null,"行唐县",7); INSERT into street VALUES (null,"灵寿县",7); -- 唐山市 INSERT into street VALUES (null,"乐亭县",8); INSERT into street VALUES (null,"迁西县",8); INSERT into street VALUES (null,"玉田县",8); -- 秦皇岛市 INSERT into street VALUES (null,"青龙满族自治县",9); INSERT into street VALUES (null,"昌黎县",9); INSERT into street VALUES (null,"卢龙县",9);
省：
package cn.hp.dao;
import cn.hp.model.Provice;
import java.util.List;
public interface ProviceInfoDao {
public List findAll();
}
package cn.hp.impl;
import cn.hp.dao.ProviceInfoDao;
import cn.hp.model.Provice;
import cn.hp.util.DBHelper;
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 ProviceInfoDaoImpl implements ProviceInfoDao {
@Override
public List findAll() {
Connection conn = DBHelper.getConn();
List list = new ArrayList();
String sql = "select * from provice";
try {
PreparedStatement ps=conn.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
while (rs.next()){
Provice p = new Provice();
p.setPid(rs.getInt(1));
p.setPname(rs.getString(2));
list.add(p);
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
}
package cn.hp.model;
public class Provice {
private int pid;
private String pname;
public Provice() {
}
public Provice(int pid, String pname) {
this.pid = pid;
this.pname = pname;
}
@Override
public String toString() {
return "Provice{" +
"pid=" + pid +
", pname='" + pname + '\'' +
'}';
}
public int getPid() {
return pid;
}
public void setPid(int pid) {
this.pid = pid;
}
public String getPname() {
return pname;
}
public void setPname(String pname) {
this.pname = pname;
}
}
package cn.hp.servlet;
import cn.hp.dao.ProviceInfoDao;
import cn.hp.impl.ProviceInfoDaoImpl;
import cn.hp.model.Provice;
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("/findprovice")
public class FindProviceServlet extends HttpServlet {
public FindProviceServlet() {
super();
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// super.doGet(req, resp);
req.setCharacterEncoding("utf-8");
resp.setContentType("text/html;charset=utf-8");
ProviceInfoDao pid = new ProviceInfoDaoImpl();
List plist=pid.findAll();
//把这个省份的集合转换成json格式的数据发送到前端页面
resp.getWriter().write(JSONObject.toJSONString(plist));
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doPost(req, resp);
}
}
市：
package cn.hp.dao;
import cn.hp.model.City;
import java.util.List;
public interface CityInfoDao {
public List findAllCity(int pid);
}
package cn.hp.impl;
import cn.hp.dao.CityInfoDao;
import cn.hp.model.City;
import cn.hp.model.Provice;
import cn.hp.util.DBHelper;
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 CityInfoDaoImpl implements CityInfoDao {
@Override
public List findAllCity(int pid) {
Connection conn = DBHelper.getConn();
List list = new ArrayList();
String sql = "select * from city where pid=?";
try {
PreparedStatement ps=conn.prepareStatement(sql);
ps.setInt(1,pid);
ResultSet rs = ps.executeQuery();
while (rs.next()){
City c=new City();
c.setCid(rs.getInt(1));
c.setCname(rs.getString(2));
c.setPid(rs.getInt(3));
list.add(c);
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
}
package cn.hp.model;
public class City {
private int cid;
private String cname;
private int pid;
public City() {
}
public City(int cid, String cname, int pid) {
this.cid = cid;
this.cname = cname;
this.pid = pid;
}
@Override
public String toString() {
return "City{" +
"cid=" + cid +
", cname='" + cname + '\'' +
", pid=" + pid +
'}';
}
public int getCid() {
return cid;
}
public void setCid(int cid) {
this.cid = cid;
}
public String getCname() {
return cname;
}
public void setCname(String cname) {
this.cname = cname;
}
public int getPid() {
return pid;
}
public void setPid(int pid) {
this.pid = pid;
}
}
package cn.hp.servlet;
import cn.hp.dao.CityInfoDao;
import cn.hp.impl.CityInfoDaoImpl;
import cn.hp.model.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("/findcitypid")
public class FindCityPidServlet extends HttpServlet{
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
resp.setContentType("text/html;charset=utf-8");
String id = req.getParameter("id");
CityInfoDao cid = new CityInfoDaoImpl();
List list = cid.findAllCity(Integer.parseInt(id));
//把城市的集合转换成json格式的字符串发送到前端页面
resp.getWriter().write(JSONObject.toJSONString(list));
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doPost(req, resp);
}
}
区：
package cn.hp.dao;
import cn.hp.model.Street;
import java.util.List;
public interface StreetInfoDao {
public List findAllStreet(int cid);
}
package cn.hp.impl;
import cn.hp.dao.StreetInfoDao;
import cn.hp.model.Provice;
import cn.hp.model.Street;
import cn.hp.util.DBHelper;
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 StreetInfoDaoImpl implements StreetInfoDao {
@Override
public List findAllStreet(int cid) {
Connection conn = DBHelper.getConn();
List list = new ArrayList();
String sql = "select * from Street where cid=?";
try {
PreparedStatement ps=conn.prepareStatement(sql);
ps.setInt(1,cid);
ResultSet rs = ps.executeQuery();
while (rs.next()){
Street s = new Street();
s.setDid(rs.getInt(1));
s.setDname(rs.getString(2));
s.setCid(rs.getInt(3));
list.add(s);
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
}
package cn.hp.model;
public class Street {
private int did;
private String dname;
private int cid;
public Street() {
}
public Street(int did, String dname, int cid) {
this.did = did;
this.dname = dname;
this.cid = cid;
}
@Override
public String toString() {
return "Street{" +
"did=" + did +
", dname='" + dname + '\'' +
", cid=" + cid +
'}';
}
public int getDid() {
return did;
}
public void setDid(int did) {
this.did = did;
}
public String getDname() {
return dname;
}
public void setDname(String dname) {
this.dname = dname;
}
public int getCid() {
return cid;
}
public void setCid(int cid) {
this.cid = cid;
}
}
package cn.hp.servlet;
import cn.hp.dao.CityInfoDao;
import cn.hp.dao.ProviceInfoDao;
import cn.hp.dao.StreetInfoDao;
import cn.hp.impl.CityInfoDaoImpl;
import cn.hp.impl.ProviceInfoDaoImpl;
import cn.hp.impl.StreetInfoDaoImpl;
import cn.hp.model.City;
import cn.hp.model.Provice;
import cn.hp.model.Street;
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("/findstreetdid")
public class FindStreetServlet extends HttpServlet {
public FindStreetServlet() {
super();
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
resp.setContentType("text/html;charset=utf-8");
String id = req.getParameter("id");
StreetInfoDao did = new StreetInfoDaoImpl();
List list=did.findAllStreet(Integer.parseInt(id));
//把这个省份的集合转换成json格式的数据发送到前端页面
resp.getWriter().write(JSONObject.toJSONString(list));
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
super.doPost(req, resp);
}
}
页面展示代码：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
Title
省
市
区
DBHelper类：
package cn.hp.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBHelper {
private static String Driver = "com.mysql.jdbc.Driver";
private static String Url = "jdbc:mysql://localhost:3306/school?characterEncoding=utf8";
private static String user = "root";
private static String pwd = "root";
public static Connection conn;
// 创建数据库连接
public static Connection getConn() {
try {
Class.forName(Driver);
conn = DriverManager.getConnection(Url, user, pwd);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return conn;
}
// 关闭数据库连接
public static void getClose() {
try {
if (conn != null) {
conn.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
// 测试数据库连接
public static void main(String[] args) {
System.out.println(getConn());
if (getConn()!=null) {
System.out.println("链接成功");
}
}
}
总结
本篇文章就到这里了，希望能给你带来帮助，也希望你能够多多关注脚本之家的更多内容！