找到一个办法： While the same element can’t be repeated in a sorted set since every element is unique, it is possible to add multiple different elements having the same score. When multiple elements have the same score, they are ordered lexicographically (they are still ordered by score as a first key, however, locally, all the elements with the same score are relatively ordered lexicographically). 根据Redis文档，由于score相同时，将默认按照字典排序（即score对应的member值排序），所以讲时间戳拼接在member原有值之前即可。