elasticsearch 操作

文档：https://www.elastic.co/guide/en/elasticsearch/reference/current/index.html

客户端：https://www.elastic.co/guide/en/elasticsearch/client/index.html

API:https://www.elastic.co/guide/en/elasticsearch/reference/6.4/search-request-from-size.html

.net

1.连接，项目中引用Nest包

var settings = new ConnectionSettings(new Uri("http://example.com:9200"))
    .DefaultIndex("people");

var client = new ElasticClient(settings);

2.索引

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

var person = new Person
{
    Id = ,
    FirstName = "Martijn",
    LastName = "Laarman"
};

var indexResponse = client.IndexDocument(person); 

var asyncIndexResponse = await client.IndexDocumentAsync(person); 

3.查询

var searchResponse = client.Search<Person>(s => s
    .From()
    .Size()
    .Query(q => q
         .Match(m => m
            .Field(f => f.FirstName)
            .Query("Martijn")
         )
    )
);

var people = searchResponse.Documents;

4.删除

var person = new Person
{
    Id =
};
var deleteResponse= client.Delete<Person>(dept);

在kibana中操作

查看

删除

添加一个新的Index

public class StudentQuery
    {
        public int StudentId { get; set; }
        public List<string> Items { get; set; }
    }

var settings = new ConnectionSettings(new Uri("http://10.15.4.155:9200/")).DefaultIndex("student");
            var client = new ElasticClient(settings);
            for (int i = ; i < ; i++)
            {
                StudentQuery student = new StudentQuery();
                student.StudentId = i;
                student.Items = new List<string>();
                student.Items.Add("Code"+i);
                student.Items.Add("Name"+i);
                student.Items.Add("CardId"+i);
                student.Items.Add("IdentityId"+i);
                var indexResponse = client.IndexDocument(student);
            }

查询

var searchResponse = client.Search<StudentQuery>(s => s.
                Query(q=>q.
                    Match(m=>m.
                        Field(f=>f.Items)
                        .Query("CardId1")
                    )
                )
            );

在kibana中查询

GET /student/studentquery/_search/
{
    "query": {
    "match": {
      "items": {
        "query": "Code8"
      }
    }
  }
}

对同一字段多个值查询

或者使用term

GET /_search
{
    "from" : 0, "size" : 10,
    "query" : {
        "term" : { "user" : "kimchy" }
    }
}

这里要注意match和term的区别

Why doesn’t the term query match my document?

简单来说就是string类型的字段在index之前会已fulltext的方式被es进行默认分词，比如放入“基金交易”，用term来查“基金”可能就查不到，用match就可以。

Java

@Service
public class ElasticService {
    @Value("${elastic.host}")
    private String host;
    @Value("${elastic.port}")
    private int port;

    private RestHighLevelClient client;

    public void index(String index, List<MetisQuestion> list) throws Exception {
        client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost(host, port, "http")));
        for(MetisQuestion o :list){
            IndexRequest request = new IndexRequest(index,"doc");
            ObjectMapper mapper=new ObjectMapper();
            String json=mapper.writeValueAsString(o);
            request.source(json, XContentType.JSON);
            IndexResponse response = client.index(request, RequestOptions.DEFAULT);
            System.out.println(response.status());
        }
    }

    public void search(String index,String key){
        client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost(host, port, "http")));
        SearchRequest searchRequest = new SearchRequest(index);
        searchRequest.types("doc");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(QueryBuilders.termQuery("question", key));
        searchRequest.source(sourceBuilder);
        getResponse(searchRequest);
    }

    public void search(String index,String key,String... values){
        client = new RestHighLevelClient(
                RestClient.builder(
                        new HttpHost(host, port, "http")));
        SearchRequest searchRequest = new SearchRequest(index);
        searchRequest.types("doc");
        SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
        sourceBuilder.query(QueryBuilders.termsQuery(key,values));
        sourceBuilder.size(5);
        searchRequest.source(sourceBuilder);
        getResponse(searchRequest);
    }

    private void getResponse(SearchRequest searchRequest) {
        try {
            SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
            SearchHits hits = searchResponse.getHits();
            for (SearchHit hit : hits) {
                String sourceAsString = hit.getSourceAsString();
                ObjectMapper mapper=new ObjectMapper();
                MetisQuestion question=mapper.readValue(sourceAsString,MetisQuestion.class);
                System.out.println(question.getQuestion());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}