redisTemplate的有序集合(zset)实例

//场景是这样的，现在需要记录用户最近浏览的职位，按浏览的时间倒序排序，只记录最近浏览的5条

//redisTemplate怎么用就不多说了

@Resource(name = "jdkRedisTemplate")
    private RedisTemplate<String, Long> redisTempalte;
    @Override
    public void addRecentBrowsingPosition(long userId, long positionId) {
        String key = RedisKeyGenerator.genRecentBrowsingPositionsKey(String.valueOf(userId));
        // 获取已缓存的最近浏览的职位
        ZSetOperations<String, Long> zSetOperations = redisTempalte.opsForZSet();
                  //zset内部是按分数来排序的，这里用当前时间做分数
        zSetOperations.add(key, positionId, System.currentTimeMillis());
                  //环形结构--4,-3,-2,-1,0,1,2,3,4
        zSetOperations.removeRange(key, 0, -6);
    }
    @Override
    public List<Long> getRecentBrowsingPositionIds(long userId) {
        if (userId <= 0) {
            return Collections.emptyList();
        }
        // 获取用户最近浏览的职位id
        String key = RedisKeyGenerator.genRecentBrowsingPositionsKey(String.valueOf(userId));
        Set<Long> positionIds = redisTempalte.opsForZSet().reverseRange(key, 0, 4);
        return new ArrayList<>(positionIds);
    }