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ajax实现省市三级联动效果(ajax级联查询)深度揭秘

文章摘要

这篇文章介绍了如何使用Spring Boot创建一个简单的Servlet(`CityServlet`),用于从数据库中获取城市信息并返回JSON格式的响应。代码中使用了`JDBC`数据源和`QueryRunner`来执行SQL查询,具体是通过`String pid`参数过滤特定的城市记录。同时,代码还实现了错误处理,能够捕获`SQLException`并打印出详细信息。文章重点突出了使用`JDBC`、`QueryRunner`以及`JSON`数据格式的相关功能。

 package servlet; 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(); } } }