无法对 numFound 进行排序，因为 numFound 不是 Solr 中的字段.
检查提到它的讨论没有得到支持，我也没有找到针对该问题的 JIRA.

Sorting on the numFound is not possible as numFound is not an field in Solr.
Check the discussion mentioning it not being supported and I did not find a JIRA open for the issue as well.