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众所周知，Elasticsearch作为搜索引擎被广泛应用在各个领域， 索引作为Elasticsearch搜索实现核心之一，Elasticsearch底层使用倒排索引对分词进行文档映射，默认使用大数据常用的相似推荐算法(TF-IDF)进行打分，既实现文档高效检索，又完成文档评分排序。在上一篇基础上，本章将说明如何定义索引，并实现完整检索客户端。

1.索引定义

下面以实战商品搜索为例，说明复杂的商品索引定义，常用关键点如下：

1. 分片和副本：定义索引分片数和副本数;
2. 分词器：analyzer，如果搜索中文，可自定义索引字段的分词器；
3. 标准化：normalizer，对字段标准化统一处理；
4. 嵌套：Elasticsearch支持嵌套搜索，常用在商品优惠活动(子文档)与商品(主文档)一起搜索。

{  "aliases": {    "index_product": {}  },  "settings": {    "index": {      "number_of_shards": 5,      "number_of_replicas": 1    },    "analysis": {      "normalizer": {        "lowercase": {          "type": "custom",          "filter": [            "lowercase"          ]        }      }    }  },  "mappings": {    "index_product": {      "_all": {        "enabled": false      },      "dynamic_templates": [        {          "attribute_values": {            "match_mapping_type": "*",            "mapping": {              "type": "keyword"            }          }        }      ],      "properties": {        "id": {          "type": "long"        },        "spuId": {          "type": "long"        },        "categoryId": {          "type": "long"        },        "categoryIds": {          "type": "long"        },        "productCode": {          "type": "keyword"        },        "shopId": {          "type": "long"        },        "shopName": {          "type": "keyword"        },        "brandId": {          "type": "long"        },        "brandName": {          "type": "text",          "analyzer": "keyword"        },        "name": {          "type": "text",          "analyzer": "ik_max_word"        },        "nameKw": {          "type": "keyword",          "normalizer": "lowercase"        },        "mainImage": {          "type": "keyword",          "index": false        },        "status": {          "type": "integer"        },        "type": {          "type": "integer"        },        "businessType": {          "type": "integer"        },        "bitTag": {          "type": "long",          "index": false        },        "updatedAt": {          "type": "date",          "format": "yyyy-MM-dd HH:mm:ss||epoch_millis"        },        "lowPrice": {          "type": "long"        },        "highPrice": {          "type": "long"        },        "keyword": {          "type": "text",          "analyzer": "ik_max_word"        },        "saleQuantity": {          "type": "long"        },        "inStock": {          "type": "integer"        },        "shopCategoryIds": {          "type": "long"        },        "source": {          "type": "integer"        },        "channelList": {          "type": "long"        },        "integral": {          "type": "long"        },        "version": {          "type": "keyword"        },        "颜色": {          "type": "keyword"        },        "尺寸": {          "type": "keyword"        },        "长度": {          "type": "keyword"        },        "priceJson": {          "type": "keyword",          "index": false        },        "activityObject": {          "type": "nested",          "properties": {            "id": {              "type": "long"            },            "code": {              "type": "keyword"            },            "warmStartAt": {              "type": "long"            },            "startAt": {              "type": "long"            },            "expiredAt": {              "type": "long"            }          }        }      }    }  }}

2. 索引客户端

搜索客户端包括如下两部分核心内容；

• 检索：查询转移，请求分发，请求结果处理，下载资源地址：；
• 定义：索引、聚合、查询，详细的实现可以参考：，下载资源地址：；

2.1 调用接口封装

/** * Copyright (c) 2020-2088 LEE POSSIBLE All Rights Reserved * Project:product-center * Package:com.leepossible.search.client * Version 1.0 * 搜索客户端接口定义 * @author 

2.2 聚合

/** * Copyright (c) 2020-2088 LEE POSSIBLE All Rights Reserved * Project:product-center * Package:com.leepossible.search.client.builder * Version 1.0 * Aggregate聚合Builder * @author 

2.3 排序

/** * Copyright (c) 2020-2088 LEE POSSIBLE All Rights Reserved * Project:product-center * Package:com.leepossible.search.client.builder * Version 1.0 * 排序builder模式 * @author 

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