ElasticSearch 学习笔记 - 5. 文档

1、新建文档

（1）一般格式

PUT blog/segmentfault/1
{
  "id":1,
  "title":"Elasticsearch简介",
  "author":"kyle",
  "content":"Elasticsearch是一个基于Lucene的搜索引擎"
}

名称	参数	说明
blog	_index	索引名
segmentfault	_type	类型名
1	_id	文档ID
1	_version	版本号

（2）未指定文档ID

POST blog/segmentfault
{
  "id":3,
  "title":"Java编程",
  "author":"kyle",
  "content":"Java面向对象程序设计"
}

（3）添加多个type
6.x之后不允许添加多个type

POST blog/csdn
{
  "id":3,
  "title":"Java编程",
  "author":"chengyuqiang",
  "content":"Java面向对象程序设计"
}

{
  "error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "Rejecting mapping update to [blog] as the final mapping would have more than 1 type: [csdn, segmentfault]"
      }
    ],
    "type": "illegal_argument_exception",
    "reason": "Rejecting mapping update to [blog] as the final mapping would have more than 1 type: [csdn, segmentfault]"
  },
  "status": 400
}

2、获取文档

GET /blog/segmentfault/1

{
  "_index": "blog",
  "_type": "segmentfault",
  "_id": "1",
  "_version": 1,
  "found": true,
  "_source": {
    "id": 1,
    "title": "Elasticsearch简介",
    "author": "kyle",
    "content": "Elasticsearch是一个基于Lucene的搜索引擎"
  }
}

3、文档搜索

（1）、检索全部

GET /blog/_search

(2)、term查询
term查询用于查找指定字段中包含指定分词的文件，只有当查询分词和文档中的分词精确匹配时才被检索到。

GET /blog/_search
{
  "query": {
    "term": {
      "content": {
        "value": "程"
      }
    }
  }
}

{
  "took": 2,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 0.2876821,
    "hits": [
      {
        "_index": "blog",
        "_type": "segmentfault",
        "_id": "V0JLZmYBnUSb-hp-GzV6",
        "_score": 0.2876821,
        "_source": {
          "id": 3,
          "title": "Java编程",
          "author": "kyle",
          "content": "Java面向对象程序设计"
        }
      }
    ]
  }
}

当查询”程序”时，title字段中找不到这样的分词，默认汉字被分为单字词。

GET /blog/_search
{
  "query": {
    "term": {
      "content": {
        "value": "程序"
      }
    }
  }
}

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 0,
    "max_score": null,
    "hits": []
  }
}

（3）terms查询

GET /blog/_search
{
  "query": {
    "terms": {
      "title": [
        "java",
        "git"
      ]
    }
  }
}
注意，经过分词后英文单词变成了小写，比如”Java”词项变成了”java”


{
  "took": 4,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 2,
    "max_score": 1,
    "hits": [
      {
        "_index": "blog",
        "_type": "segmentfault",
        "_id": "V0JLZmYBnUSb-hp-GzV6",
        "_score": 1,
        "_source": {
          "id": 3,
          "title": "Java编程",
          "author": "kyle",
          "content": "Java面向对象程序设计"
        }
      },
      {
        "_index": "blog",
        "_type": "segmentfault",
        "_id": "2",
        "_score": 1,
        "_source": {
          "id": 2,
          "title": "Git简介",
          "author": "lalala",
          "content": "Git是一个版本控制软件"
        }
      }
    ]
  }
}

（4）match查询
与term精确查询不同，对于match查询，只要被查询字段中存在任何一个词项被匹配，就会搜索到该文档。

GET /blog/_search
{
  "query": {
    "match": {
      "content": "程序"
    }
  }
}

{
  "took": 18,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 0.5753642,
    "hits": [
      {
        "_index": "blog",
        "_type": "segmentfault",
        "_id": "V0JLZmYBnUSb-hp-GzV6",
        "_score": 0.5753642,
        "_source": {
          "id": 3,
          "title": "Java编程",
          "author": "kyle",
          "content": "Java面向对象程序设计"
        }
      }
    ]
  }
}

4、更新文档

（1）更新数据
文档在Elasticsearch中是不可变的，不能修改。如果我们需要修改文档，Elasticsearch实际上重建新文档替换掉旧文档。

POST /blog/segmentfault/2
{
  "id":2,
  "title":"Git简介",
  "author":"hahaha",
  "content":"Git是一个分布式版本控制软件"
}

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

NOTE:

• 版本加1。
• "result": "updated"，因为同索引同类型下已经存在同ID的文档。
• 在ES内部，_version为1的文件已经被标记“删除”，并添加了一个完整的新文档。旧文档不会立即消失，但是不能再访问它。

（2）更新字段

POST /blog/segmentfault/2/_update
{
  "script": {
    "source": "ctx._source.content=\"GIT是一个开源的分布式版本控制软件\""  
  }
}

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

（3）添加新字段

POST /blog/segmentfault/2/_update
{
  "script": "ctx._source.posttime=\"2018-10-09\""
}

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

（4）查询更新

POST blog/_update_by_query
{
  "script": {
    "source": "ctx._source.category=params.category",
    "lang":"painless",
    "params":{"category":"git"}
  },
  "query":{
    "term": {"title":"git"}
  }
}

5、删除文档

DELETE /blog/segmentfault/2

{
  "_index": "blog",
  "_type": "segmentfault",
  "_id": "2",
  "_version": 7,
  "result": "deleted",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "_seq_no": 6,
  "_primary_term": 1
}