Elasticsearch 简明教程
Elasticsearch - Search APIs
此 API 用于在 Elasticsearch 中搜索内容。用户可以通过使用查询字符串作为参数发送 GET 请求或在 POST 请求的信息主体中发布查询来进行搜索。基本上，所有搜索 API 都是多索引多类型。
This API is used to search content in Elasticsearch. A user can search by sending a get request with query string as a parameter or they can post a query in the message body of post request. Mainly all the search APIS are multi-index, multi-type.
Multi-Index
Elasticsearch 允许我们搜索所有索引或某些特定索引中存在的文档。例如，如果我们需要搜索名称中包含中心的所有文档，我们可以像这里所示的那样进行操作：
Elasticsearch allows us to search for the documents present in all the indices or in some specific indices. For example, if we need to search all the documents with a name that contains central, we can do as shown here −
GET /_all/_search?q=city:paprola在运行上述代码后，我们会得到以下响应：
On running the above code, we get the following response −
{
"took" : 33,
"timed_out" : false,
"_shards" : {
"total" : 7,
"successful" : 7,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 1,
"relation" : "eq"
},
"max_score" : 0.9808292,
"hits" : [
{
"_index" : "schools",
"_type" : "school",
"_id" : "5",
"_score" : 0.9808292,
"_source" : {
"name" : "Central School",
"description" : "CBSE Affiliation",
"street" : "Nagan",
"city" : "paprola",
"state" : "HP",
"zip" : "176115",
"location" : [
31.8955385,
76.8380405
],
"fees" : 2200,
"tags" : [
"Senior Secondary",
"beautiful campus"
],
"rating" : "3.3"
}
}
]
}
}URI Search
在搜索操作中可以使用统一资源标识符传入许多参数：
Many parameters can be passed in a search operation using Uniform Resource Identifier −
S.No |
Parameter & Description |
1 |
Q This parameter is used to specify query string. |
2 |
lenient This parameter is used to specify query string.Format based errors can be ignored by just setting this parameter to true. It is false by default. |
3 |
fields This parameter is used to specify query string. |
4 |
sort We can get sorted result by using this parameter, the possible values for this parameter is fieldName, fieldName:asc/fieldname:desc |
5 |
timeout We can restrict the search time by using this parameter and response only contains the hits in that specified time. By default, there is no timeout. |
6 |
terminate_after We can restrict the response to a specified number of documents for each shard, upon reaching which the query will terminate early. By default, there is no terminate_after. |
7 |
from The starting from index of the hits to return. Defaults to 0. |
8 |
size It denotes the number of hits to return. Defaults to 10. |
Request Body Search
我们还可以在请求正文中使用查询 DSL 指定查询，在之前的章节中已经给出了许多示例。这里给出了一个这样的示例：
We can also specify query using query DSL in request body and there are many examples already given in previous chapters. One such example is given here −
POST /schools/_search
{
"query":{
"query_string":{
"query":"up"
}
}
}在运行上述代码后，我们会得到以下响应：
On running the above code, we get the following response −
{
"took" : 11,
"timed_out" : false,
"_shards" : {
"total" : 1,
"successful" : 1,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : {
"value" : 1,
"relation" : "eq"
},
"max_score" : 0.47000363,
"hits" : [
{
"_index" : "schools",
"_type" : "school",
"_id" : "4",
"_score" : 0.47000363,
"_source" : {
"name" : "City Best School",
"description" : "ICSE",
"street" : "West End",
"city" : "Meerut",
"state" : "UP",
"zip" : "250002",
"location" : [
28.9926174,
77.692485
],
"fees" : 3500,
"tags" : [
"fully computerized"
],
"rating" : "4.5"
}
}
]
}
}