redis使用示例

package com.atguigu.gulimall.product;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import org.junit.jupiter.api.Test;
import org.junit.platform.commons.util.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import java.util.List;
import java.util.Map;
import java.util.UUID;

@SpringBootTest
public class RedisTest {

    @Autowired
    StringRedisTemplate redisTemplate;

    @Test
    public void testRedis() {
        ValueOperations<String, String> ops = redisTemplate.opsForValue();

        //保存
        ops.set("hello", "world" + UUID.randomUUID().toString());

        //查询
        String hello = ops.get("hello");
        System.out.println("之前保存的数据是：" + hello);
    }

    @Test
    public Map<String, List<Catelog2Vo>> getCatelogJson() {
        String catelogJSON = redisTemplate.opsForValue().get("catelogJSON");
        if(StringUtils.isBlank(catelogJSON)) {
            //缓存中没有，查询数据库
            Map<String, List<Catelog2Vo>> catelogJsonFromDb = getCatelogJsonFromDb();
            //查到的数据再放入缓存，并将对象转为json类型
            String s = JSON.toJSONString(catelogJsonFromDb);
            redisTemplate.opsForValue().set("catelogJSON", s);
            return catelogJsonFromDb;
        }

        //转换为我们指定的对象。反序列化：因为之前存入redis前序列换为json类型的数据了，现在取出来也要转为最初的对象类型数据。
        Map<String, List<Catelog2Vo>> result = JSON.parseObject(catelogJSON, new TypeReference<Map<String, List<Catelog2Vo>>>() {});
        return result;
    }

    private Map<String, List<Catelog2Vo>> getCatelogJsonFromDb() {
        return null;
    }
    public class Catelog2Vo {
    }

}