1.ElasticSearch简介
Elasticsearch是一个分布式搜索服务，提供Restful API，底层基于Lucene，采用多shard（分片）的方式保证数据安全，并且提供自动resharding的功能，github等大型的站点也是采用了ElasticSearch作为其搜索服务。
我们经常需要添加检索功能，开源的 ElasticSearch 是目前全文搜索引擎的首选。因为它可以快速的存储、搜索和分析海量数据。Spring Boot通过整合Spring Data ElasticSearch为我们提供了非常便捷的检索功能支持。
2.ElasticSearch概念
3.ElasticSearch搭建
(1).docker搭建ElasticSearch
在docker上搭建ElasticSearch环境
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[root@hosystem ~]# docker search elasticsearch NAME DESCRIPTION STARS OFFICIAL AUTOMATED elasticsearch Elasticsearch is a powerful open source sear… 4675 [OK] [root@hosystem ~]# docker pull elasticsearch:6.8.4 6.8.4: Pulling from library/elasticsearch d8d02d457314: Pull complete d3dfcf2fdd68: Pull complete c8ffe81b87d5: Pull complete 3fdfbe1a7641: Pull complete dba32acd6977: Pull complete cf006e61e0b6: Pull complete a9425533f3f3: Pull complete Digest: sha256:f4be4f53677e009df3db81f3f6a98908040968bd9a27bdfdf936c651d78e0319 Status: Downloaded newer image for elasticsearch:6.8.4 docker.io/library/elasticsearch:6.8.4 [root@hosystem ~]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE redis latest 62f1d3402b78 5 days ago 104MB rabbitmq 3-management 68898be27496 4 weeks ago 186MB rabbitmq latest ea2bf0a30abf 4 weeks ago 156MB hello-world latest bf756fb1ae65 10 months ago 13.3kB elasticsearch 6.8.4 25476914cc66 12 months ago 955MB |
注：若出现manifest for elasticsearch:latest not found: manifest unknown: manifest unknown问题；
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只需要指定版本号即可 elasticsearch:latest |
(2).启动ElasticSearch
启动ElasticSearch的时候我们需要指定内存大小，否则会出现错误.
由于elasticsearch默认分配jvm空间大小为2g，内存不足分配导致错误.max virtual memory areas vm.max_count(65530) is too low...
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[root@hosystem ~]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE redis latest 62f1d3402b78 5 days ago 104MB rabbitmq 3-management 68898be27496 4 weeks ago 186MB rabbitmq latest ea2bf0a30abf 4 weeks ago 156MB hello-world latest bf756fb1ae65 10 months ago 13.3kB elasticsearch 6.8.4 25476914cc66 12 months ago 955MB [root@hosystem ~]# docker run -e ES_JAVA_OPTS="-Xms256m -Xmx256m" -d -p 9200:9200 -p 9300:9300 --name ES01 25476914cc66 6c91eee08c02a2c3eeda3264d215c73678518881011dc494c121dc4fb658ed06 [root@hosystem ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 6c91eee08c02 25476914cc66 "/usr/local/bin/dock…" 10 seconds ago Up 7 seconds 0.0.0.0:9200->9200/tcp,0.0.0.0:9300->9300/tcp ES01 |
(3).访问ElasticSearch管理界面
[1].防火墙设置
如果访问出现我们需要检查下是否配置成功，启动是否成功。还有就是防火墙是否已经配置可允许通过9200端口.
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[root@hosystem ~]# firewall-cmd --zone=public --add-port=9200/tcp --permanent |
[2].vm.max_map_count
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[root@hosystem ~]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 7ed1a0faa39a 25476914cc66 "/usr/local/bin/dock…" About a minute ago Exited (78) 55 seconds ago ES01 [root@hosystem ~]# docker logs -f -t --tail 10 7ed1a0faa39a #内存不足 https://blog.csdn.net/qq_34756221/article/details/105550037 2020-11-02T14:58:05.423337218Z [1]: max virtual memory areas vm.max_map_count [65530] is too low,increase to at least [262144] 2020-11-02T14:58:05.502461403Z [2020-11-02T14:58:05,497][INFO ][o.e.n.Node ] [5KFPGEX] closed 2020-11-02T14:58:05.506628526Z [2020-11-02T14:58:05,506][INFO ][o.e.x.m.p.NativeController] [5KFPGEX] Native controller process has stopped - no new native processes can be started |
4.ElasticSearch使用
官方文档：https://www.elastic.co/guide/index.html
(1).下载postmanCanary
(2).创建数据
通过postman的put请求增加员工数据
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PUT /megacorp/employee/1 { "first_name" : "John", "last_name" : "Smith", "age" : 25, "about" : "I love to go rock climbing", "interests": [ "sports","music" ] }
PUT /megacorp/employee/2 { "first_name" : "Jane", "last_name" : "Smith", "age" : 32, "about" : "I like to collect rock albums", "interests": [ "music" ] }
PUT /megacorp/employee/3 { "first_name" : "Douglas", "last_name" : "Fir", "age" : 35, "about": "I like to build cabinets", "interests": [ "forestry" ] } |
(3).检索文档
将 HTTP 命令由 PUT 改为 GET 可以用来检索文档，同样的，可以使用 DELETE 命令来删除文档，以及使用 HEAD 指令来检查文档是否存在。如果想更新已存在的文档，只需再次 PUT .
[1].获取员工
使用GET请求
[2].检验员工是否存在
使用HEAD请求
(4).轻量搜索
[1].搜索所有雇员
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GET /megacorp/employee/_search |
[2].搜索姓氏为Smith的雇员
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GET /megacorp/employee/_search?q=last_name:Smith |
(5).查询表达式
参考文档：
https://www.elastic.co/guide/index.html
https://www.elastic.co/guide/cn/elasticsearch/guide/current/index.html
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