大纲

 一、导入省市县数据表(t_region)

 二、引入jar包

三、导入所需util类（整体框架）

四、编写代码

 1、配置数据库相关信息(数据库名、用户名、密码)    config.propreties

#oracle9i
#driver=oracle.jdbc.driver.OracleDriver
#url=jdbc:oracle:thin:@localhost:1521:orcl
#user=scott
#pwd=123#sql2005
#driver=com.microsoft.sqlserver.jdbc.SQLServerDriver
#url=jdbc:sqlserver://localhost:1433;DatabaseName=test1
#user=sa
#pwd=123#mysql
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8
user=root
pwd=1234

 2、创建数据库中对应数据表（t_region）的省市县实体类，即 Region.java

package com.zking.jquery.entity;
/*** 地区实体类* @author gss**/
public class Region {private long id;//编号private long parent_id;//父级编号private long region_id;private long region_parent_id;private String region_name;//名称private Integer region_type;//类型 1省 2市 3县public long getId() {return id;}public void setId(long id) {this.id = id;}public long getParent_id() {return parent_id;}public void setParent_id(long parent_id) {this.parent_id = parent_id;}public long getRegion_id() {return region_id;}public void setRegion_id(long region_id) {this.region_id = region_id;}public long getRegion_parent_id() {return region_parent_id;}public void setRegion_parent_id(long region_parent_id) {this.region_parent_id = region_parent_id;}public String getRegion_name() {return region_name;}public void setRegion_name(String region_name) {this.region_name = region_name;}public Integer getRegion_type() {return region_type;}public void setRegion_type(Integer region_type) {this.region_type = region_type;}public Region() {super();}@Overridepublic String toString() {return "Region [id=" + id + ", parent_id=" + parent_id + ", region_id=" + region_id + ", region_parent_id="+ region_parent_id + ", region_name=" + region_name + ", region_type=" + region_type + "]";}	
}

3、 工具类  BaseDao.java

package com.zking.jquery.dao;import java.sql.Connection;
import java.sql.ParameterMetaData;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import com.zking.jquery.util.DBHelper;
import com.zking.jquery.util.PageBean;public class BaseDao {public static interface CallBack{public List forEach(ResultSet rs) throws SQLException;}/*** 增删改通用方法* @param sql* @param params*/public void executeUpdate(String sql,Object[] params) {Connection conn=null;PreparedStatement stmt=null;try {conn=DBHelper.getConnection();stmt=conn.prepareStatement(sql);ParameterMetaData metadata = stmt.getParameterMetaData();for (int i = 0; i < metadata.getParameterCount(); i++) {stmt.setObject(i+1, params[i]);}int i = stmt.executeUpdate();if(i<1)throw new RuntimeException("执行失败，影响行数为0");} catch (Exception e) {e.printStackTrace();throw new RuntimeException(e);}finally {DBHelper.close(conn, stmt, null);}}/*** 查询方法* @param sql* @param params*/public List executeQuery(String sql,PageBean pageBean,CallBack callBack){Connection conn=null;PreparedStatement stmt=null;ResultSet rs=null;try {conn=DBHelper.getConnection();//判断是否分页if(null!=pageBean&&pageBean.isPagination()) {//第一次查询返回总记录数String countSql=this.getCountSql(sql);stmt=conn.prepareStatement(countSql);rs=stmt.executeQuery();if(rs.next()) {Object obj=rs.getObject(1);pageBean.setTotal(Integer.parseInt(obj.toString()));}//第二次查询返回指定页码数并满足条件的分页结果集sql=this.getPagerSql(sql, pageBean);}stmt=conn.prepareStatement(sql);rs=stmt.executeQuery();//遍历结果集return callBack.forEach(rs);} catch (Exception e) {e.printStackTrace();}finally {DBHelper.close(conn, stmt, rs);}return null;}/*** 将普通SQL语句转换成查询总记录数的SQL语句* @param sql* @return*/private String getCountSql(String sql) {return "select count(1) from ("+sql+") t1";}/*** 将普通SQL语句转换成查询分页记录集的SQL语句* @param sql* @param pageBean* @return*/private String getPagerSql(String sql,PageBean pageBean) {return sql+" Limit "+pageBean.getStartIndex()+","+pageBean.getRows();}
}

4、数据操作类 RegionDao.java 继承BaseDao.java

package com.zking.jquery.dao;import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import com.zking.jquery.entity.Region;
import com.zking.jquery.util.CommonUtils;
import com.zking.jquery.util.StringUtils;public class RegionDao extends BaseDao{//查询public List queryRegionLst(Region region){String sql="select id,region_id,parent_id,region_parent_id,"+ "region_name,region_type from t_region where 1=1";//判断不为空if(StringUtils.isNotBlank(region.getParent_id()+""))sql+=" and parent_id="+region.getParent_id();return super.executeQuery(sql, null, new CallBack() {@Overridepublic List forEach(ResultSet rs) throws SQLException {try {return CommonUtils.toList(rs, Region.class);} catch (Exception e) {e.printStackTrace();}return null;}});}
}

5、 工具类 CommonUtils.java

package com.zking.jquery.util;import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;public class CommonUtils {/*** 根据ResultSet数据集，利用反射机制动态赋值并返回List* @param rs ResultSet数据集* @param clazz 实体类对象* @return 返回List实体集合* @throws Exception*/public static  List toList(ResultSet rs,Class clazz) throws Exception{//定义实体集合List lst=new ArrayList();//获取ResultSet的metadata列信息ResultSetMetaData metaData = rs.getMetaData();//获取对象属性集合Field[] fields=clazz.getDeclaredFields();//循环ResultSetwhile(rs.next()) {//反射机制实例化T obj = clazz.newInstance();for (int i = 0; i < metaData.getColumnCount(); i++) {//获取列名String columnName=metaData.getColumnLabel(i+1).toUpperCase();for (Field field : fields) {//判断属性名与列名是否相同if(field.getName().toUpperCase().equals(columnName)) {//获取属性对应的set方法名，方法名首字母大写String methodName="set"+field.getName().substring(0, 1).toUpperCase()+field.getName().substring(1);//获取属性对应的set方法Method method = obj.getClass().getDeclaredMethod(methodName, field.getType());//设置访问权限method.setAccessible(true);//执行set方法，将数据存储到对象中的相应属性中method.invoke(obj, rs.getObject(columnName));break;}}}lst.add(obj);}return lst;}/*** 多表查询时返回结果集,利用反射机制赋值 * @param rs* @return 返回List>* @throws Exception*/public static List> toList(ResultSet rs) throws Exception{//定义实体集合List> lst=new ArrayList>();//获取ResultSet的metadata列信息	ResultSetMetaData metaData = rs.getMetaData();Map set=null;while(rs.next()) {set=new HashMap();for (int i = 0; i < metaData.getColumnCount(); i++) {String columnName=metaData.getColumnLabel(i+1);set.put(columnName, rs.getObject(columnName));}lst.add(set);}return lst;}
}

6、测试Dao类是否有误        RegionDaoTest.java

package com.zking.jquery.dao;import static org.junit.jupiter.api.Assertions.*;
import java.util.List;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import com.zking.jquery.entity.Region;class RegionDaoTest {//实例化一个dao类对象private RegionDao regionDao = new RegionDao();private Region region;@BeforeEachvoid setUp() throws Exception {region=new Region();}@Testvoid testQueryRegionLst() {//给父级编号赋值region.setParent_id(7459);//调用Dao类查询方法List lst=regionDao.queryRegionLst(region);for (Region reg: lst) {System.out.print(reg);}}
}

测试结果没有报错，可以继续下一步

 7、RegionAction.java

package com.zking.jquery.action;import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.zking.jquery.dao.RegionDao;
import com.zking.jquery.entity.Region;
import com.zking.mvc.framework.Action;
import com.zking.mvc.framework.DriverModel;public class RegionAction extends Action implements DriverModel {private RegionDao regionDao=new RegionDao();private Region region=new Region();private ObjectMapper mapper=new ObjectMapper();@Overridepublic Region getModel() {return region;}@Overridepublic String execute(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {List lst = regionDao.queryRegionLst(region);mapper.writeValue(res.getOutputStream(), lst);return null;}
}

1、创建 address.jsp 页面。先在 js 中引入 jquery.min.js 。

 将 jquery.min.js 引入到 address.jsp 中

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







省市县三级联动 lxy
-----请选择----- -----请选择----- -----请选择-----

打印结果：

2、在 web.xml 中配置过滤器

Jquery_addressindex.htmlindex.htmindex.jspdefault.htmldefault.htmdefault.jspFilterEncodingcom.zking.jquery.util.EncodingFilterFilterEncoding/*ActionServletcom.zking.mvc.framework.ActionServletconfig/mvc.xmlActionServlet*.action

3、将 mvc.xml 导入到 src 根目录下  配置RegionAction

]>

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