Ajax级联菜单,通过dwr框架实现省份城市级联效果

package com.dwr.dao.impl; import java.util.ArrayList; import java.util.List; import com.dwr.dao.Dao; import com.dwr.model.City; import com.dwr.model.Province; import java.sql.*; /** * 数据访问类 * @author 马果 * */ public class DaoImpl implements Dao{ private Connection con = null; private PreparedStatement pst = null; private ResultSet rs = null; /** * 构造方法 */ public DaoImpl(){ String url = "jdbc:mysql://localhost:3306/ajax"; try { Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection(url,"root","root"); } catch (Exception e) { e.printStackTrace(); } } /** * 得到选中省份下所有的城市 * @param pid * @return {@link List} * */ public List<City> getCitys(Integer pid) { String sql = "select * from city where pid = ?"; List<City> list = new ArrayList<City>(); try { pst = con.prepareStatement(sql); pst.setInt(1,pid); rs = pst.executeQuery(); while(rs.next()){ City c = new City(); c.setCid(rs.getInt("cid")); c.setCname(rs.getString("cname")); list.add(c); } } catch (Exception e) { e.printStackTrace(); } return list; } /** * 得到所有的省份 * @return {@link List} * * */ public List<Province> getProvinces() { String sql = "select * from province"; List<Province> list = new ArrayList<Province>(); try { pst = con.prepareStatement(sql); rs = pst.executeQuery(); while(rs.next()){ Province p = new Province(); p.setPid(rs.getInt("pid")); p.setPname(rs.getString("pname")); list.add(p); } } catch (Exception e) { e.printStackTrace(); } return list; } }