简介
ES是一个开源的高扩展的分布式全文搜索引擎，它可以近乎实时的存储、检索数据。
环境配置
Elasticsearch 7.8.0 | Elastic
最新版本的需要Java11的环境，7.8版本的java1.8可用。
windows上点击bin/elasticsearch.bat启动，localhost:9200
倒排索引
| keyword | id |
|---|
| name | 1001,1002 |
| zhang | 1001 |
使用内容搜索到id
索引的增删查
使用restfull风格的请求，发送PUT、DELETE、GET
URL：http://localhost:9200/shopping shopping是索引名称。
增加：PUT
删除：DELETE
查询：GET
查看全部索引信息：GET：http://localhost:9200/_cat/indices?v
文档的增删改
增加
POST：http://localhost:9200/shopping/_doc
request body中添加json字符串，如：
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| {
"name":"小猪",
"age":18
}
|
成功的响应：
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| {
"_index": "shopping",
"_type": "_doc",
"_id": "HKPeWH8BmpBnrMt18vUi",
"_version": 1,
"result": "created",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 0,
"_primary_term": 1
}
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从响应信息中看到，返回的ID为HKPeWH8BmpBnrMt18vUi，若想使用自定义的ID，则需要修改请求的URL，如：http://localhost:9200/shopping/_doc/1001 id为1001
查询
根据id查询
GET：http://localhost:9200/shopping/_doc/1001
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| {
"_index": "shopping",
"_type": "_doc",
"_id": "1001",
"_version": 2,
"_seq_no": 2,
"_primary_term": 1,
"found": true,
"_source": {
"name": "小猪",
"age": 18
}
}
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查询索引下的所有文档信息
GET：http://localhost:9200/shopping/_search
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| {
"took": 56,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "shopping",
"_type": "_doc",
"_id": "HKPeWH8BmpBnrMt18vUi",
"_score": 1.0,
"_source": {
"name": "小猪",
"age": 18
}
},
{
"_index": "shopping",
"_type": "_doc",
"_id": "1001",
"_score": 1.0,
"_source": {
"name": "小猪",
"age": 18
}
}
]
}
}
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修改
覆盖性修改
PUT：http://localhost:9200/shopping/_doc/1001
request Body：
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| {
"name":"小狗",
"age":18
}
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response：
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| {
"_index": "shopping",
"_type": "_doc",
"_id": "1001",
"_version": 3,
"result": "updated",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 3,
"_primary_term": 1
}
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局部数据修改
POST：http://localhost:9200/shopping/_update/1001
request body：
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| {
"doc":{
"age":20
}
}
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response：
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| {
"_index": "shopping",
"_type": "_doc",
"_id": "1001",
"_version": 5,
"result": "updated",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 5,
"_primary_term": 1
}
|
删除
DELETE：http://localhost:9200/shopping/_doc/1001
response：
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| {
"_index": "shopping",
"_type": "_doc",
"_id": "1001",
"_version": 6,
"result": "deleted",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"_seq_no": 6,
"_primary_term": 1
}
|
复杂查询
ES的搜索会对用户输入的内容进行分词操作，然后查询出与之相关的内容并按照相关度_score降序排列，比如：要查询的内容为{"name":"小猪"} ，则查询结果中包含所有name属性中包括小、猪的信息，例如：小猪、小鸡、大猪…..
条件查询
查询年龄为18的信息：
GET：http://localhost:9200/shopping/_search
request body：
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| {
"query":{
"match":{
"age":18
}
}
}
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response：
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| {
"took": 2,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "shopping",
"_type": "_doc",
"_id": "HKPeWH8BmpBnrMt18vUi",
"_score": 1.0,
"_source": {
"name": "小猪",
"age": 18
}
}
]
}
}
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分页查询
GET ：http://localhost:9200/shopping/_search
request body：
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| {
"query":{
"match_all":{
}
},
"from":0,
"size":1,
"_source":["name"],
"sort":{
"age":{
"order":"desc"
}
}
}
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参数：
from从那条开始查，第一个为0
size每页显示的数据的条数
_source指定要查询的属性，不加默认全部
sort对查询的内容进行排序后分页，此处的意思是根据age进行降序排序。降序：desc，升序：esc
response：
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| {
"took": 1,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": 1.0,
"hits": [
{
"_index": "shopping",
"_type": "_doc",
"_id": "HKPeWH8BmpBnrMt18vUi",
"_score": 1.0,
"_source": {
"name": "小猪",
"age": 18
}
}
]
}
}
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多条件参数
与关系
request body：
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| {
"query": {
"bool": {
"must": [
{
"match": {
"name": "小鸡"
}
},
{
"match": {
"age": 18
}
}
]
}
}
}
|
must为一个数组，代表必须满足的所有条件。
或关系
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| {
"query": {
"bool": {
"should": [
{
"match": {
"name": "小鸡"
}
},
{
"match": {
"age": 18
}
}
]
}
}
}
|
should为一个数组，进行查询时取或的关系。
范围限制
限制属性的取值范围，比如年龄>20
request body：
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| {
"query": {
"bool": {
"filter":{
"range":{
"age":{
"gt":20
}
}
}
}
}
}
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response：
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| {
"took": 5,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 2,
"relation": "eq"
},
"max_score": 0.0,
"hits": [
{
"_index": "shopping",
"_type": "_doc",
"_id": "IKMHWX8BmpBnrMt1ePVZ",
"_score": 0.0,
"_source": {
"name": "小鸡",
"age": 22
}
},
{
"_index": "shopping",
"_type": "_doc",
"_id": "IaMHWX8BmpBnrMt1qvUl",
"_score": 0.0,
"_source": {
"name": "阿姨",
"age": 60
}
}
]
}
}
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完全匹配
由前文可知，ES会对内容进行分词操作，如何进行完全匹配呢？
request body：
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| {
"query": {
"match_phrase":{
"name":"小猪"
}
},
"highlight":{
"fields":{
"name":{
}
}
}
}
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只会查询到name为“小猪”的信息，highlight设置高亮显示：
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| {
"took": 53,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 1,
"relation": "eq"
},
"max_score": 1.5606477,
"hits": [
{
"_index": "shopping",
"_type": "_doc",
"_id": "HKPeWH8BmpBnrMt18vUi",
"_score": 1.5606477,
"_source": {
"name": "小猪",
"age": 18
},
"highlight": {
"name": [
"<em>小</em><em>猪</em>"
]
}
}
]
}
}
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聚合查询
分组
request body：
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| {
"aggs":{
"age-group":{
"terms":{
"field":"age"
}
}
},
"size":0
}
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response
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| {
"took": 3,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": null,
"hits": []
},
"aggregations": {
"age-group": {
"doc_count_error_upper_bound": 0,
"sum_other_doc_count": 0,
"buckets": [
{
"key": 18,
"doc_count": 1
},
{
"key": 20,
"doc_count": 1
},
{
"key": 22,
"doc_count": 1
},
{
"key": 60,
"doc_count": 1
}
]
}
}
}
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平均值
response body：
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| {
"aggs":{
"age-group":{
"avg":{
"field":"age"
}
}
},
"size":0
}
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response：
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| {
"took": 3,
"timed_out": false,
"_shards": {
"total": 1,
"successful": 1,
"skipped": 0,
"failed": 0
},
"hits": {
"total": {
"value": 4,
"relation": "eq"
},
"max_score": null,
"hits": []
},
"aggregations": {
"age-group": {
"value": 30.0
}
}
}
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映射
创建映射
PUT：http://localhost:9200/user/_mapping
request body：
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| {
"properties":{
"name":{
"type":"text",
"index":true
},
"sex":{
"type":"keyword",
"index":true
},
"tel":{
"type":"keyword",
"index":false
}
}
}
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name可以被分词查询，sex必须是完全匹配，不能通过tel进行查询。
