Redis 模糊查询key, SCAN、KEYS

Redis 模糊查询key, SCAN、KEYS

keys

keys的操作会导致数据库暂时被锁住，其他的请求都会被堵塞；业务量大的时候会出问题

redisTemplate.keys(pattern + "*")

参考：https://blog.youkuaiyun.com/a774630093/article/details/102606343

redisTemplate.executeWithStickyConnection

    /**
     * 获得缓存的基本对象列表
     *
     * @param pattern 字符串前缀
     * @param pageSize 分页大小
     * @return 对象列表
     */
    public List<String> scan(String pattern, int pageSize) {
        List<String> result = new ArrayList<>();
        try {
            ScanOptions options = ScanOptions.scanOptions().count(pageSize).match(pattern+"*").build();
            RedisSerializer<String> redisSerializer = redisTemplate.getKeySerializer();
            Cursor cursor = (Cursor) redisTemplate.executeWithStickyConnection(redisConnection ->
                    new ConvertingCursor<>(redisConnection.scan(options), redisSerializer::deserialize));
            result = JSON.parseObject(JSON.toJSONString(cursor), List.class);
            //关闭cursor
            cursor.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

使用spring-data-redis封装好的scan方法

redisConnection.scan

参考：https://note.dolyw.com/cache/10-Redis-Scan-Keys.html

public List<String> scan(String pattern) {
        List<String> result = new ArrayList<>();
        Cursor<byte[]> cursor = null;
        try {
            cursor = (Cursor) redisTemplate.execute((RedisCallback) redisConnection ->
              redisConnection.scan(ScanOptions.scanOptions().match(pattern + "*").count(1000).build()));
            while (cursor.hasNext()) {
                result.add(new String(cursor.next()));
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (cursor != null) {
                try {
                    cursor.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return result;
    }