# 設(shè)置 key 為 value, 并將過期時(shí)間設(shè)置為 10 秒鐘 
SET key value EX 10 # 獲取 key 的剩余過期時(shí)間 TTL key

// 設(shè)置鍵為mykey的值，確保它在30秒之后過期
redisTemplate.opsForValue().set("mykey", "Hello, Redis!");
redisTemplate.expire("mykey", 30, TimeUnit.SECONDS);

// 查看mykey的生存時(shí)間（以秒為單位）
redisTemplate.ttl("mykey");

// 查看mykey的生存時(shí)間（以毫秒為單位）
redisTemplate.pttl("mykey");

// 取消mykey的生存時(shí)間
redisTemplate.persist("mykey");

# 設(shè)置Redis最大內(nèi)存為100MB
maxmemory 100mb

# 設(shè)置淘汰策略為L(zhǎng)RU
maxmemory-policy allkeys-lru

// 將mykey的生存時(shí)間設(shè)置為10秒，并標(biāo)記為VOLATILE
redisTemplate.expire("mykey", 10, TimeUnit.SECONDS);
redisTemplate.execute(new RedisCallback<Boolean>() {
    @Override
    public Boolean doInRedis(RedisConnection connection) throws DataAccessException {
        // 將mykey標(biāo)記為VOLATILE
        connection.setEx(redisTemplate.getKeySerializer().serialize("mykey"), 10000L,
                redisTemplate.getValueSerializer().serialize("Hello, Redis!"));
        return true;
    }
});

redisTemplate.execute(new RedisCallback<String>() {
    @Override
    public String doInRedis(RedisConnection connection) throws DataAccessException {
        return connection.info();
    }
});
# 使用redis-cli工具查看Redis內(nèi)存使用情況
$ redis-cli info memory

public class CacheDemo {
    private static finalStringRedisTemplate redisTemplate = new StringRedisTemplate();

    static {
        // 設(shè)置Redis服務(wù)器的主機(jī)名和端口號(hào)
        RedisStandaloneConfiguration config = new RedisStandaloneConfiguration("localhost", 6379);
        // 創(chuàng)建連接池
        LettuceConnectionFactory factory = new LettuceConnectionFactory(config);
        factory.afterPropertiesSet();
        // 設(shè)置RedisTemplate的連接工廠
        redisTemplate.setConnectionFactory(factory);
        redisTemplate.afterPropertiesSet();
    }

    public static void main(String[] args) {
        // 設(shè)置鍵值對(duì)緩存
        redisTemplate.opsForValue().set("key1", "value1");
        redisTemplate.opsForValue().set("key2", "value2");

        // 設(shè)置key1的生存時(shí)間為10秒，并標(biāo)記為VOLATILE
        redisTemplate.expire("key1", 10, TimeUnit.SECONDS);
        redisTemplate.execute(new RedisCallback<Boolean>() {
            @Override
            public Boolean doInRedis(RedisConnection connection) throws DataAccessException {
                connection.setEx(redisTemplate.getKeySerializer().serialize("key1"), 10000L,
                        redisTemplate.getValueSerializer().serialize("value1"));
                return true;
            }
        });

        // 查看key1的剩余生存時(shí)間
        System.out.println(redisTemplate.getExpire("key1"));

        // 設(shè)置Redis的最大內(nèi)存為10MB，淘汰策略為L(zhǎng)RU
        redisTemplate.execute(new RedisCallback<String>() {
            @Override
            public String doInRedis(RedisConnection connection) throws DataAccessException {
                connection.getConfig("maxmemory");
                connection.getConfig("maxmemory-policy", "allkeys-lru");
                return null;
            }
        });

        // 查看Redis內(nèi)存使用情況
        System.out.println(redisTemplate.execute(RedisServerCommands::info).get("used_memory"));
    }
}