【ES-实战入门】

1、document数据格式

面向文档的搜索分析引擎
（1）应用系统的数据结构都是面相对象的，复杂的。

public class Employee{
    private String email;
    private String firstName;
    private EmployeeInfo info;
}
public class EmployeeInfo{
    private String bio;
    private Integer age;
    private String[] interes;
}

EmployeeInfo info = new EmployeeInfo();
info.setBio("curios and modest")
    info.setage(30);
info.setInterests(new String[]{"bike","climb"});

Employee employee = new Employee();
employee.setEmail("zhangsna@164.com")
    employee.setFirstName("san")
        empolyee.setInfo(info)

employee对象；包含了Employee类自己的属性还有一个info对象，
当我们存到关系型数据库的时候，还需要拆开到两个表中，但是ES不用，所以是面相对象。
（2）对象数据存储到数据库中，只能拆解开来，变为扁平的多个表，每次查询的时候还得还原回原来对象格式，相当麻烦
(3) ES 是面相文档的，文档中存储的数据结构，与面向对象的数据结构是一样的。
（4）ES的document用JSON数据格式表达

2、电商网站商品管理案例背景介绍

（1）对商品CRUD
（2） 执行简单结构化查询
（3）可以执行简单的全文检索，以及复杂的短语检索

3、简单集群操作

（1）快速检查集群的健康状况

GET _cat/health?v

epoch      timestamp cluster       status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1663923665 09:01:05  elasticsearch green           1         1      3   3    0    0        0             0                  -                100.0%

如何快速了解集群的健康状况？green、yellow、red?
status

green:每个索引的primary shard和 replica shard都是active状态的
yellow: 每个索引的Primary shard都是active状态的，但是部分replica shard不是active状态，处于不可用状态
red: 不是所有索引的Primary shard都是active状态的，部分索引有数据丢失

（2）快速查看集群中有哪些索引

Get /_cat/indices?v

(3) 简单的索引操作

创建索引: PUT /test_index?pretty

{
  "acknowledged" : true,
  "shards_acknowledged" : true,
  "index" : "test_index"
}

删除索引: DELETE /test_index?pretty

{
  "acknowledged" : true
}

4、商品的CRUD的操作

(1) 新增商品: 新增文档，建立索引

put /index/type/id

PUT /ecommerce/product/1
{
  "name":"gaolujie yagao",
  "desc":"gaoxiao meibai",
  "price": 30,
  "producer": "gaolujie producer"
}

返回的值为：
{
  "_index" : "ecommerce",
  "_type" : "product",
  "_id" : "1",
  "_version" : 1,
  "result" : "created",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 0,
  "_primary_term" : 1
}
PUT /ecommerce/product/1
{
  "name":"gaolujie yagao",
  "desc":"gaoxiao meibai",
  "price": 30,
  "producer": "gaolujie producer"
}
PUT /ecommerce/product/2
{
  "name":"jiajieshi yagao",
  "desc":"youxiaofangzhu",
  "price": 25,
  "producer": "jiajieshi producer"
}
PUT /ecommerce/product/3
{
  "name":"zhonghua yagao",
  "desc":"caobenzhiwu",
  "price": 40,
  "producer": "zhonghua producer"
}

es 会自动创建index和type ,不需要提前创建，而且es默认会对ducument每个field都建立倒排索引

(2) 查询商品:检索文档

GET /index/type/id
GET /ecommerce/product/1
{
  "_index" : "ecommerce",
  "_type" : "product",
  "_id" : "1",
  "_version" : 1,
  "_seq_no" : 0,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "gaolujie yagao",
    "desc" : "gaoxiao meibai",
    "price" : 30,
    "producer" : "gaolujie producer"
  }
}

（3） 修改商品：替换文档

PUT /ecommerce/product/1
{
  "name":"jiajiehsi yagao",
  "desc":"gaoxiao meibai",
  "price": 30,
  "producer": "gaolujie producer"
}

{
  "_index" : "ecommerce",
  "_type" : "product",
  "_id" : "1",
  "_version" : 2,
  "result" : "updated",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 3,
  "_primary_term" : 1
}

这里变成了updated

替换方式有一个不好，必须带上所有的filed，才能去进行信息的修改。

（4）修改商品：更新文档

POST /ecommerce/product/1/_update (API)
{
  "doc":{
    "name":"jiaqiangban gaolujieyagao"
  }
}

{
  "_index" : "ecommerce",
  "_type" : "product",
  "_id" : "1",
  "_version" : 3,
  "result" : "updated",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 4,
  "_primary_term" : 1
}

(5) 删除商品

DELETE /ecommerce/product/1

{
  "_index" : "ecommerce",
  "_type" : "product",
  "_id" : "1",
  "_version" : 4,
  "result" : "deleted",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 5,
  "_primary_term" : 1
}


GET /ecommerce/product/1


{
  "_index" : "ecommerce",
  "_type" : "product",
  "_id" : "1",
  "found" : false
}