ajax实现省市三级联动效果（ajax级联查询）深度揭秘

import DButil.DataSourceUtil;
import com.alibaba.fastjson.JSON;
import domain.City;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import javax.jws.WebService;
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.sql.SQLException;
import java.util.List;

@WebServlet(“/getCitys”)
public class CityServlet extends HttpServlet
{
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
{
resp.setContentType(“application/json;charset=utf8”);
QueryRunner queryRunner=new QueryRunner(DataSourceUtil.getDataSource());
String pid=req.getParameter(“pid”);
String sql=”select * from City where pid=?”;
try
{
List<City> cities=queryRunner.query(sql, new BeanListHandler<City>(City.class), pid);
Object toJSON=JSON.toJSON(cities);
resp.getWriter().print(toJSON);
} catch (SQLException e)
{
e.printStackTrace();
}
}
}