어떻게 Redis를 캐시로 사용하여 사용자가 데이터에 접근하는 사용자 체험을 강화합니까

/**     
         1、        mysql Provice ，    nosql   redis   
         2、    ，     jar 
         3、  jedis/utils/domain/dao/service/web     
         4、      
*/
//  
span style="color:#bababa;">html>
lang="en">

 charset="UTF-8">
 
 src=<span style="color:#a5c261;">"js/jquery-3.3.1.min.js"<span style="color:#e8bf6a;">>
 <br><span style="color:#e8bf6a;"> <span style="color:#9876aa;">$(<span style="color:#cc7832;font-weight:bold;">function () {<br><span style="color:#278009;">//  ajax  <br><span style="color:#278009;"> <span style="color:#9876aa;">$.<span style="color:#ffc66d;">get(<span style="color:#6a8759;">"provinceServlet"<span style="color:#cc7832;">,{}<span style="color:#cc7832;">,<span style="color:#cc7832;font-weight:bold;">function (data) {<br><span style="color:#278009;">//1、  select<br><span style="color:#278009;"> <span style="color:#cc7832;font-weight:bold;">var province=<span style="color:#9876aa;">$(<span style="color:#6a8759;">"#province")<span style="color:#cc7832;">;<br><span style="color:#cc7832;"> <span style="color:#278009;">//2、  json  <br><span style="color:#278009;"> <span style="color:#9876aa;">$(data).<span style="color:#ffc66d;">each(<span style="color:#cc7832;font-weight:bold;">function () {<br><span style="color:#278009;">//3、  option<br><span style="color:#278009;"> <span style="color:#cc7832;font-weight:bold;">var option =<span style="color:#6a8759;">"<option name ='"+<span style="color:#cc7832;font-weight:bold;">this.<span style="color:#9876aa;">id+<span style="color:#6a8759;">"'>"+<span style="color:#cc7832;font-weight:bold;">this.<span style="color:#9876aa;">name+<span style="color:#6a8759;">"</option>"<span style="color:#cc7832;">;<br><span style="color:#cc7832;"> <span style="color:#278009;">//4、  select append  option<br><span style="color:#278009;"> province.<span style="color:#ffc66d;">append(option)<span style="color:#cc7832;">;<br><span style="color:#cc7832;"> })<span style="color:#cc7832;">;<br><span style="color:#cc7832;"> })<span style="color:#cc7832;">;<br><span style="color:#cc7832;"> })<span style="color:#cc7832;">;<br><span style="color:#cc7832;"> <span style="color:#e8bf6a;">


 name="province" id="province"> --     -- 



//Web     

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、  service  
 ProvinceService service = new ProvinceServiceImpl();
 List provinces = service.findAll();
 //2、   list json  
 ObjectMapper mapper = new ObjectMapper();
 String json = mapper.writeValueAsString(provinces);*/
// System.out.println(json);
 //1、  service  
 ProvinceService service = new ProvinceServiceImpl();
 String json = service.findAllJson();
 //3、    
 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 

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 {
//  dao
 private ProvinceDao dao = new ProvinceDaoImpl();
 @Override
 public List findAll() {
return dao.findAll();
 }

@Override
 public String findAllJson() {
//1、       redis  
 Jedis jedis = JedisPoolUtils.getJedis();
 //2、  redis province  
 String province_json = jedis.get("province");
 //3、  province_json    null
 if(province_json == null || province_json.length()<=0){
//4、  redis   province   ,           
 List ps = dao.findAll();
 ObjectMapper mapper = new ObjectMapper();
 try {
 province_json = mapper.writeValueAsString(ps);
 } catch (JsonProcessingException e) {
 e.printStackTrace();
 }
 System.out.println("     redis，       。。。。");
 jedis.set("province",province_json);
 //  jedis，     
 jedis.close();
 }else {
 System.out.println("    redis  。。。。");
 }
return province_json;
 }
}

//dao 

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、      JdbcTemplate
 private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
 @Override
 public List findAll() {
//1、  sql  
 String sql = "select * from province";
 //2、  sql
 List list = template.query(sql, new BeanPropertyRowMapper(Province.class));
 System.out.println(list);
 return list;
 }
}

//Jedis   

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   
 *       ，         
 *          
 */
public class JedisPoolUtils {
private static JedisPool jedisPool;
 static {
//      
 InputStream is = JedisPoolUtils.class.getClassLoader().getResourceAsStream("jedis.properties");
 //  Properties  
 Properties prop = new Properties();
 try {
 prop.load(is);
 } catch (IOException e) {
 e.printStackTrace();
 }
//    ，   JedisPoolConfig() 
 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")));
 }

/**
 *       
 * @return
 */
 public static Jedis getJedis(){
return jedisPool.getResource();
 }
}

//JDBCUtils   

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      Durid   
 */
public class JDBCUtils {

private static DataSource ds ;

 static {

try {
//1.      
 Properties pro = new Properties();
 //  ClassLoader      ，       
 InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
 pro.load(is);

 //2.        
 ds = DruidDataSourceFactory.createDataSource(pro);

 } catch (IOException e) {
 e.printStackTrace();
 } catch (Exception e) {
 e.printStackTrace();
 }
 }

/**
 *        
 */
 public static DataSource getDataSource(){
return ds;
 }


/**
 *     Connection  
 */
 public static Connection getConnection() throws SQLException {
return ds.getConnection();
 }
}