Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is ElasticsearchStatusException[Elasticsearch exception [type=search_phase_execution_exception, reason=all shards failed]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Fielddata is disabled on text fields by default. Set fielddata=true on [category] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.]]; nested: ElasticsearchException[Elasticsearch exception [type=illegal_argument_exception, reason=Fielddata is disabled on text fields by default. Set fielddata=true on [category] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.]];] with root cause

这个异常信息是关于 Elasticsearch 的，大致意思是：在执行搜索时，所有分片都失败了。原因是在查询中使用了文本字段（text fields）的聚合（aggregation）功能，但是默认情况下，文本字段是禁用了 Fielddata（一个 ElasticSearch 中的内存结构，用于支持聚合、排序等操作）的。要解决这个问题，可以在查询中设置 `fielddata=true`，或者使用关键字字段（keyword field）代替文本字段。