一、概述
Elasticsearch，简称为 ES， ES 是一个开源的高扩展的分布式全文搜索引擎,同时也是面向文档型数据库，在ES中一条数据就是一个文档。在学习ES之前需要先了解一些概念：
Index（索引）：不同于Mysql的索引，ES中的索引相当于Mysql的数据库，当我们向ES插入数据的时候，需要指定要插入到哪个索引之下。
Document（文档）：ES中存储的就是一条条文档，ES可以通过关键字检索到相应的文档。
Fields（字段）：与MySQL中的字段相同
二、使用
1.索引-创建
在Postman中，向ES服务器发送PUT请求：
localhost:9200/lol
请求后，服务器返回响应：
{
"acknowledged": true, //响应结果
"shards_acknowledged": true,//分片结果
"index": "lol" //索引名称
}
2.索引-查询
在 Postman 中，向 ES 服务器发 GET 请求 ：
localhost:9200/_cat/indices?v
3.文档-创建
在Postman中，向ES服务器发送POST请求：
localhost:9200/lol/_doc
请求体JSON内容为：
{
"名字":"卡沙",
"称号":"虚空之女",
"定位":"下路、中路"
}
4.主键查询&全查询
全查询:在 Postman 中，向 ES 服务器发 GET 请求 ：
localhost:9200/lol/_search
响应：
{
"took": 442,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 5,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "lol",
"_type": "_doc",
"_id": "uI6dVoEB32Jj3QrMO2F-",
"_score": 1.0,
"_source": {
"名字": "卡沙",
"称号": "虚空之女",
"定位": "下路、中路"
}
},
{
"_index": "lol",
"_type": "_doc",
"_id": "vY4HV4EB32Jj3QrMIGHs",
"_score": 1.0,
"_source": {
"名字": "易",
"称号": "无极剑圣",
"定位": "打野"
}
},
{
"_index": "lol",
"_type": "_doc",
"_id": "vo4HV4EB32Jj3QrMiGF0",
"_score": 1.0,
"_source": {
"名字": "艾希",
"称号": "寒冰射手",
"定位": "下路、辅助"
}
},
{
"_index": "lol",
"_type": "_doc",
"_id": "v44HV4EB32Jj3QrMtmEa",
"_score": 1.0,
"_source": {
"名字": "孙悟空",
"称号": "齐天大圣",
"定位": "上路、打野"
}
},
{
"_index": "lol",
"_type": "_doc",
"_id": "wI4HV4EB32Jj3QrMzGHj",
"_score": 1.0,
"_source": {
"名字": "阿狸",
"称号": "九尾狐妖",
"定位": "中单"
}
}
]
}
}
主键查询：
localhost:9200/lol/_doc/vY4HV4EB32Jj3QrMIGHs
{
"_index": "lol",
"_type": "_doc",
"_id": "vY4HV4EB32Jj3QrMIGHs",
"_version": 1,
"_seq_no": 1,
"_primary_term": 1,
"found": true,
"_source": {
"名字": "易",
"称号": "无极剑圣",
"定位": "打野"
}
}
5.条件查询
在 Postman 中，向 ES 服务器发 GET 请求 ：
localhost:9200/lol/_search
同时带上查询条件:
{
"query":{
"match":{
"名字":"齐天大圣"
}
}
}
查询结果：
{
"took": 262,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 3.4526575,
"hits": [
{
"_index": "lol",
"_type": "_doc",
"_id": "v44HV4EB32Jj3QrMtmEa",
"_score": 3.4526575,
"_source": {
"名字": "孙悟空",
"称号": "齐天大圣",
"定位": "上路、打野"
}
}
]
}
6.多条件查询
查询条件：
“must”相当于与，“should”相当于或
{
"query":{
"bool":{
"must":[{
"match":{
"名字":"艾希"
}
},{
"match":{
"名字":"卡沙"
}
}]
}
}
}
7.全文检索
查询条件:
{
"query":{
"match":{
"名字":"孙易"
}
}
}
响应：
{
"took": 69,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 1.7427702,
"hits": [
{
"_index": "lol",
"_type": "_doc",
"_id": "vY4HV4EB32Jj3QrMIGHs",
"_score": 1.7427702,
"_source": {
"名字": "易",
"称号": "无极剑圣",
"定位": "打野"
}
},
{
"_index": "lol",
"_type": "_doc",
"_id": "v44HV4EB32Jj3QrMtmEa",
"_score": 1.1508858,
"_source": {
"名字": "孙悟空",
"称号": "齐天大圣",
"定位": "上路、打野"
}
}
]
}
}
8.聚合查询
在 Postman 中，向 ES 服务器发 GET请求 ：
localhost:9200/lol/_search
{
"aggs":{
//聚合操作
"定位聚合":{
"terms":{
//分组
"field":"定位"
}
}
}
}