使用ajax+servlet+jsp+jdbc实现分级选择省市.zip

package com.example.dao; import com.example.entity.City; import com.example.entity.Province; import java.sql.*; import java.util.ArrayList; import java.util.List; public class QueryDao { private Connection conn; private PreparedStatement pst; private ResultSet rs; private String url="jdbc:mysql://127.0.0.1:3306/springdb"; private String username = "root"; private String password = "123"; String sql = ""; //查询所有的省份信息 public List<Province> queryProvinceList(){ List<Province> provinces = new ArrayList<>(); Province p = null; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(url,username,password); sql = "select id,name,jiancheng,shenghui from province order by id"; pst = conn.prepareStatement(sql); rs = pst.executeQuery(); while(rs.next()){ p = new Province(); p.setId(rs.getInt("id")); p.setName(rs.getString("name")); p.setJiancheng(rs.getString("jiancheng")); p.setShenghui(rs.getString("shenghui")); provinces.add(p); } }catch (Exception e){ System.out.println(e); }finally { try { if (rs != null){ rs.close(); } if (pst != null){ pst.close(); } if (conn != null){ pst.close(); } }catch (Exception e){ System.out.println(e); } } return provinces; } //查询所有的市信息 public List<City > queryCityList(Integer provinceId){ List<City> cities = new ArrayList<>(); City c = null; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(url,username,password); sql = "select id, name from city where provinceid=?"; pst = conn.prepareStatement(sql); pst.setInt(1,provinceId); rs = pst.executeQuery(); while(rs.next()){ c = new City(); c.setId(rs.getInt("id")); c.setName(rs.getString("name")); cities.add(c); } }catch (Exception e){ System.out.println(e); }finally { try { if (rs != null){ rs.close(); } if (pst != null){ pst.close(); } if (conn != null){ pst.close(); } }catch (Exception e){ System.out.println(e); } } return cities; } }