利用Redis对MySQL查询做缓存提高查询速度

MySQL配置

2. application.properties中配置数据源

spring.datasource.url=jdbc:mysql://localhost:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8&useSSL=false

spring.datasource.username=root

spring.datasource.password=root

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

3. 添加maven依赖

		

		    org.mybatis.spring.boot

		    mybatis-spring-boot-starter

		    2.0.0

		

4. 编写mapper接口并在其中写实体类(实体类写在外面也可以)

import org.apache.ibatis.annotations.Insert;

import org.apache.ibatis.annotations.Mapper;

import org.apache.ibatis.annotations.Select;



import java.util.List;



@Mapper

public interface MapTestMapper {



    public class MapTest{

        private String start_ip;

        private String end_ip;

        private String info_json;



        public String getStart_ip() {

            return start_ip;

        }



        public void setStart_ip(String start_ip) {

            this.start_ip = start_ip;

        }



        public String getEnd_ip() {

            return end_ip;

        }



        public void setEnd_ip(String end_ip) {

            this.end_ip = end_ip;

        }



        public String getInfo_json() {

            return info_json;

        }



        public void setInfo_json(String info_json) {

            this.info_json = info_json;

        }

    }

    @Insert("INSERT INTO map_geo VALUES (#{start_ip},#{end_ip},#{info_json})")

    public void insertMap(MapTest maptest);



    @Select("SELECT info_json FROM map_geo WHERE start_ip <= #{ipNum} and end_ip > #{ipNum}")

    public List selectMap(String ipNum);


}

5. 使用

@Service
public class MapUtil {
    @Autowired
    private MapTestMapper mapTestMapper;
    
    public void insertMapIntoMysql() throws Exception{
            geoSql.setIp("127.0.0.1");
            geoSql.setInfo_json("本机");
            mapGeoMapper.inserGeotMap(geoSql);
        }
    }

Redis配置

2. application.properties中配置Redis源

spring.redis.database=0
spring.redis.host=localhost
spring.redis.port=6379
spring.redis.password=
spring.redis.pool.max-active=8
spring.redis.pool.max-wait=-1
spring.redis.pool.max-idle=8
spring.redis.pool.min-idle=0
spring.redis.timeout=5000

3. 添加maven依赖

		org.springframework.boot
		spring-boot-starter-data-redis
	

4. 编写redis工具类

   StringRedisTemplate继承了RedisTemplate类，唯一的区别就是其是专门针对String字符串进行了转码，如果是字符串操作，没有转码，则推荐使用StringRedisTemplate。

import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import com.alibaba.fastjson.JSON;

@Service
public class RedisUtil {

	@Autowired
	private StringRedisTemplate redisTemplate;
	
	public void setString(String key, String value){
		redisTemplate.opsForValue().set(key, value);
		redisTemplate.expire(key, 0, TimeUnit.SECONDS);
	}
	public void getString(String key){
		redisTemplate.opsForValue().get(key);
	}

}

使用

@Service

public class CacheService {

    private final Logger logger = LoggerFactory.getLogger(getClass());
    @Autowired
    private EsUtil esUtil;
    @Autowired
    private RedisUtil redisUtil;
    @Autowired
    private MapTestMapper mapTestMapper;
    public JSONObject getIpInfo(String ipNum){
        JSONObject jsonObject = new JSONObject();
        //若redis存在，则直接从redis中取
        String geoInfo = redisUtil.getString(ipNum);
        if(StringUtils.isEmpty(geoInfo)){
        //若redis中不存在，则从数据库中取值并赋给redis
            List list = mapTestMapper.selectMap(ipNum);
            if(list != null && list.size() > 0){
                geoInfo = list.get(0).getInfo_json();
                redisUtil.setString(ipNum, geoInfo);
            }else{
                return jsonObject;
            }
        }
        jsonObject = JSONObject.parseObject(geoInfo);
        return jsonObject;
    }