/**完成步骤 1、创建关系型数据库mysql的Provice库，同时启动nosql系列的redis数据库 2、创建项目，导入相关的jar包 3、创建jedis/utils/domain/dao/service/web项目框架包 4、书写相关代码*///页面<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>Title</title> <script src="js/jquery-3.3.1.min.js"></script> <script> $(function () { //发送ajax请求 $.get("provinceServlet",{},function (data) { //1、获取select var province=$("#province"); //2、遍历json数组 $(data).each(function () { //3、创建option var option ="<option name =‘"+this.id+"‘>"+this.name+"</option>"; //4、调用select的append追加option province.append(option); }); }); }); </script></head><body> <select name="province" id="province"> <option>--请选择省份--</option> </select></body></html>
//Web层代码实现
package cn.hope.web.servlet;
import cn.hope.domain.Province;import cn.hope.service.ProvinceService;import cn.hope.service.impl.ProvinceServiceImpl;import com.fasterxml.jackson.databind.ObjectMapper;
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.util.List;
/** * @author newcityman * @date 2019/9/20 - 23:57 */@WebServlet("/provinceServlet")public class ProvinceServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /* //1、调用service查询 ProvinceService service = new ProvinceServiceImpl(); List<Province> provinces = service.findAll(); //2、序列化list为json数据 ObjectMapper mapper = new ObjectMapper(); String json = mapper.writeValueAsString(provinces);*/// System.out.println(json); //1、调用service查询 ProvinceService service = new ProvinceServiceImpl(); String json = service.findAllJson(); //3、响应结果 response.setContentType("application/json;charset=utf-8"); response.getWriter().write(json); }
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); }}
//service层
package cn.hope.service.impl;
import cn.hope.dao.ProvinceDao;import cn.hope.dao.impl.ProvinceDaoImpl;import cn.hope.domain.Province;import cn.hope.jedis.utils.JedisPoolUtils;import cn.hope.service.ProvinceService;import com.fasterxml.jackson.core.JsonProcessingException;import com.fasterxml.jackson.databind.ObjectMapper;import redis.clients.jedis.Jedis;import redis.clients.jedis.JedisPool;
import java.util.List;
/** * @author newcityman * @date 2019/9/20 - 23:50 */public class ProvinceServiceImpl implements ProvinceService { //申明dao private ProvinceDao dao = new ProvinceDaoImpl(); @Override public List<Province> findAll() { return dao.findAll(); }
@Override public String findAllJson() { //1、通过工具类获取redis连接 Jedis jedis = JedisPoolUtils.getJedis(); //2、获取redis中province的值 String province_json = jedis.get("province"); //3、判断province_json值是否为null if(province_json == null || province_json.length()<=0){ //4、说明redis中没有province的数据,需要从数据库中查找数据 List<Province> ps = dao.findAll(); ObjectMapper mapper = new ObjectMapper(); try { province_json = mapper.writeValueAsString(ps); } catch (JsonProcessingException e) { e.printStackTrace(); } System.out.println("第一次访问redis，数据来之数据库。。。。"); jedis.set("province",province_json); //释放jedis，回归连接池 jedis.close(); }else { System.out.println("数据来之redis缓存。。。。"); } return province_json; }}
//dao层
package cn.hope.dao.impl;
import cn.hope.dao.ProvinceDao;import cn.hope.domain.Province;import cn.hope.utils.JDBCUtils;import org.springframework.jdbc.core.BeanPropertyRowMapper;import org.springframework.jdbc.core.JdbcTemplate;
import java.util.List;
/** * @author newcityman * @date 2019/9/20 - 23:29 */public class ProvinceDaoImpl implements ProvinceDao { //1、声明成员变量JdbcTemplate private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource()); @Override public List<Province> findAll() { //1、定义sql语句 String sql = "select * from province"; //2、执行sql List<Province> list = template.query(sql, new BeanPropertyRowMapper<Province>(Province.class)); System.out.println(list); return list; }}
//Jedis工具包
package cn.hope.jedis.utils;
import redis.clients.jedis.Jedis;import redis.clients.jedis.JedisPool;import redis.clients.jedis.JedisPoolConfig;
import java.io.IOException;import java.io.InputStream;import java.util.Properties;
/** * @author newcityman * @date 2019/9/20 - 0:33 * JedisPool工具类 * 加载配置文件，配置连接池的连接池 * 提供获取连接的方法 */public class JedisPoolUtils { private static JedisPool jedisPool; static { //读取配置文件 InputStream is = JedisPoolUtils.class.getClassLoader().getResourceAsStream("jedis.properties"); //创建Properties对象 Properties prop = new Properties(); try { prop.load(is); } catch (IOException e) { e.printStackTrace(); } //获取数据，设置到JedisPoolConfig()中 JedisPoolConfig config = new JedisPoolConfig(); config.setMaxIdle(Integer.parseInt( prop.getProperty("maxTotal"))); config.setMaxTotal(Integer.parseInt(prop.getProperty("maxIdle"))); jedisPool=new JedisPool(config,prop.getProperty("host"),Integer.parseInt(prop.getProperty("port"))); }
/** * 获取连接方法 * @return */ public static Jedis getJedis(){ return jedisPool.getResource(); }}
//JDBCUtils工具包
package cn.hope.utils;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;import java.io.IOException;import java.io.InputStream;import java.sql.Connection;import java.sql.SQLException;import java.util.Properties;
/** * JDBC工具类 使用Durid连接池 */public class JDBCUtils {
private static DataSource ds ;
static {
try { //1.加载配置文件 Properties pro = new Properties(); //使用ClassLoader加载配置文件，获取字节输入流 InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"); pro.load(is);
//2.初始化连接池对象 ds = DruidDataSourceFactory.createDataSource(pro);
} catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } }
/** * 获取连接池对象 */ public static DataSource getDataSource(){ return ds; }
/** * 获取连接Connection对象 */ public static Connection getConnection() throws SQLException { return ds.getConnection(); }}
原文地址：https://www.cnblogs.com/newcityboy/p/11565158.html
时间： 2024-12-11 07:18:48