ElasticSearch版本：lucene_version: "6.6.1"
报错原因：ElasticSearch无法对类型为text的字段进行聚合查询。
方案一：
因此我们需要将es对应的索引库中的字段增加一个 fielddata:true; fielddata 默认被禁用，因为使用之后聚合查询会消耗大量的堆内存。因此慎用。
方案二：（推荐）
一般来说使用 将text类型修改为keyword 即可 因此 对应的pojo实体类也要修改
@Field(index = true,store = true,type = FieldType.Keyword)
private String brandName;
若使用 fielddata 操作如下
注意：若查询城市 "成都" 聚合之后为 "成" ，"都"
开启如下：
可以使用postman 直接update
格式：
put请求
http://ip地址:端口/索引库名/存储类型/_mapping
eg:
{
"docs":{
"properties":{
"brandName":{
"store":true,
"type":"text",
"fielddata":true
}
}
}
}
对应异常：
java.lang.IllegalArgumentException: Fielddata is disabled on text fields by default. Set fielddata=true on [brandName] 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.
at org.elasticsearch.index.mapper.TextFieldMapper$TextFieldType.fielddataBuilder(TextFieldMapper.java:336) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.index.fielddata.IndexFieldDataService.getForField(IndexFieldDataService.java:111) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.index.query.QueryShardContext.getForField(QueryShardContext.java:166) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.aggregations.support.ValuesSourceConfig.resolve(ValuesSourceConfig.java:96) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder.resolveConfig(ValuesSourceAggregationBuilder.java:297) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder.doBuild(ValuesSourceAggregationBuilder.java:290) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.aggregations.support.ValuesSourceAggregationBuilder.doBuild(ValuesSourceAggregationBuilder.java:39) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.aggregations.AbstractAggregationBuilder.build(AbstractAggregationBuilder.java:126) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.aggregations.AggregatorFactories$Builder.build(AggregatorFactories.java:347) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.SearchService.parseSource(SearchService.java:655) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.SearchService.createContext(SearchService.java:485) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.SearchService.createAndPutContext(SearchService.java:461) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.search.SearchService.executeDfsPhase(SearchService.java:226) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.action.search.SearchTransportService$5.messageReceived(SearchTransportService.java:332) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.action.search.SearchTransportService$5.messageReceived(SearchTransportService.java:329) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.transport.RequestHandlerRegistry.processMessageReceived(RequestHandlerRegistry.java:69) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.transport.TransportService$7.doRun(TransportService.java:654) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:674) ~[elasticsearch-6.4.3.jar:6.4.3]
at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37) ~[elasticsearch-6.4.3.jar:6.4.3]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[na:1.8.0_202]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[na:1.8.0_202]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_202]
