elasticsearch的学习（二）：Java api操作elasticsearch

简介

使用Java api操作elasticsearch

创建maven项目

pom.xml文件

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>elasticsearchTest</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>elasticsearchTest</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.elasticsearch</groupId>
      <artifactId>elasticsearch</artifactId>
      <version>7.8.0</version>
    </dependency>
    <!-- elasticsearch 的客户端 -->
    <dependency>
      <groupId>org.elasticsearch.client</groupId>
      <artifactId>elasticsearch-rest-high-level-client</artifactId>
      <version>7.8.0</version>
    </dependency>
    <!-- elasticsearch 依赖 2.x 的 log4j -->
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-api</artifactId>
      <version>2.8.2</version>
    </dependency>
    <dependency>
      <groupId>org.apache.logging.log4j</groupId>
      <artifactId>log4j-core</artifactId>
      <version>2.8.2</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.9</version>
    </dependency>
    <!-- junit 单元测试 -->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
    </dependency>
  </dependencies>
</project>

创建索引

package org.christ.es;
import org.apache.http.HttpHost;
import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
import org.elasticsearch.action.admin.indices.create.CreateIndexResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestClientBuilder;
import org.elasticsearch.client.RestHighLevelClient;
import java.io.IOException;

public class elasticSearchTest {
    public static void main(String[] args) throws IOException {
        //es客户端
        RestHighLevelClient restHighLevelClient = new RestHighLevelClient(
                RestClient.builder(new HttpHost("localhost",9200,"http"))
        );
        //创建索引
        CreateIndexRequest request = new CreateIndexRequest("user");
        CreateIndexResponse createIndexResponse = restHighLevelClient.indices().create(request, RequestOptions.DEFAULT);
       //响应状态
        boolean acknowledged = createIndexResponse.isAcknowledged();
        System.out.println("操作是否成功："+ acknowledged);
        //关闭es客户端
        restHighLevelClient.close();
    }
}

验证

使用postman发送get请求：http://localhost:9200/_cat/indices?v

查询索引

       GetIndexRequest request = new GetIndexRequest("user");
        GetIndexResponse getIndexResponse = restHighLevelClient.indices().get(request, RequestOptions.DEFAULT);
        System.out.println(getIndexResponse.getMappings());
        System.out.println(getIndexResponse.getAliases());
        System.out.println(getIndexResponse.getSettings());

删除索引

        DeleteIndexRequest request = new DeleteIndexRequest("user");
        AcknowledgedResponse delete = restHighLevelClient.indices().delete(request, RequestOptions.DEFAULT);
        System.out.println(delete.isAcknowledged());

添加数据

创建user类

```java
package org.christ.pojo;

public class user {
    private String name;
    private String sex;
    private Integer age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }
}

插入数据

        //插入数据
        IndexRequest indexRequest = new IndexRequest();
        indexRequest.index("user").id("1");
        user user = new user();
        user.setName("christ");
        user.setSex("man");
        user.setAge(20);
        //转换成json
        ObjectMapper objectMapper = new ObjectMapper();
        String s = objectMapper.writeValueAsString(user);
        indexRequest.source(s, XContentType.JSON);
        
        IndexResponse index = restHighLevelClient.index(indexRequest, RequestOptions.DEFAULT);
        System.out.println(index.getResult());

验证

postman发送get请求：http://localhost:9200/user/_doc/1

修改数据

        UpdateRequest updateRequest = new UpdateRequest();
        updateRequest.index("user").id("1");
        updateRequest.doc(XContentType.JSON,"sex","superman");
        UpdateResponse update = restHighLevelClient.update(updateRequest, RequestOptions.DEFAULT);
        System.out.println(update.getResult());

验证

postman发送get请求：http://localhost:9200/user/_doc/1

查询数据

        GetRequest getRequest = new GetRequest();
        getRequest.index("user").id("1");
        GetResponse documentFields = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);
        System.out.println(documentFields.getSourceAsString());

删除数据

        DeleteRequest deleteRequest = new DeleteRequest();
        deleteRequest.index("user").id("1");
        DeleteResponse delete = restHighLevelClient.delete(deleteRequest, RequestOptions.DEFAULT);
        System.out.println(delete.status());

批量插入数据

        BulkRequest bulkRequest = new BulkRequest();
        bulkRequest.add(new IndexRequest().index("user").id("2").source(XContentType.JSON,"name","jack"));
        bulkRequest.add(new IndexRequest().index("user").id("3").source(XContentType.JSON,"name","john"));
        BulkResponse bulk = restHighLevelClient.bulk(bulkRequest, RequestOptions.DEFAULT);
        System.out.println(bulk.getItems());

批量删除数据

        //批量删除数据
        BulkRequest bulkRequest = new BulkRequest();
        bulkRequest.add(new DeleteRequest().index("user").id("2"));
        bulkRequest.add(new DeleteRequest().index("user").id("3"));
        BulkResponse bulk = restHighLevelClient.bulk(bulkRequest, RequestOptions.DEFAULT);
        System.out.println(bulk);

验证

postman发送get请求：http://localhost:9200/user/_search

全量查询

 SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()));
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        System.out.println(hits);
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

条件查询

        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");
        searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.termQuery("sex","girl")));
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

和全量查询的区别是：

searchRequest.source(new SearchSourceBuilder().query(QueryBuilders.termQuery("sex","girl")));

QueryBuilders.matchAllQuery()换成了有条件的QueryBuilders.termQuery(“sex”,“girl”)

分页查询

 SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");
        //SearchSourceBuilder提取出来
        SearchSourceBuilder query = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());
        //第1页，展示两条数据
        query.from(0);
        query.size(2);
        searchRequest.source(query);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        System.out.println(hits);
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

把全量查询中的searchRequest.source()括号中的条件提取出来，设置from和size属性。

排序查询

        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");
        SearchSourceBuilder query = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());
        query.sort("age", SortOrder.DESC);
        searchRequest.source(query);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        System.out.println(hits);
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

把全量查询中的searchRequest.source()括号中的条件提取出来，设置sort属性。

查询过滤字段

 SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");
        SearchSourceBuilder query = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());
        String[] excludes={};
        String[] includes={"name"};
        query.fetchSource(includes,excludes);
        searchRequest.source(query);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        System.out.println(hits);
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

SearchSourceBuilder 构建条件的时候，有一个fetchSource（）方法，第一个参数就是包含哪些字段，第二个参数就是排除哪些字段。

条件查询

        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");

        SearchSourceBuilder query = new SearchSourceBuilder();
        BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
//        boolQueryBuilder.should(QueryBuilders.matchQuery("age","23"));
//        boolQueryBuilder.should(QueryBuilders.matchQuery("age","18"));
        boolQueryBuilder.must(QueryBuilders.matchQuery("name","christ"));
        query.query(boolQueryBuilder);
        searchRequest.source(query);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        System.out.println(hits);
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

范围查询

        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");

        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        RangeQueryBuilder age = QueryBuilders.rangeQuery("age");
        age.gt(20);
        searchSourceBuilder.query(age);
        searchRequest.source(searchSourceBuilder);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        System.out.println(hits);
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

模糊查询

        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");

        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        //name字符有一个不同也可以查出来
        searchSourceBuilder.query(QueryBuilders.fuzzyQuery("name","chris").fuzziness(Fuzziness.ONE));
        searchRequest.source(searchSourceBuilder);
        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        SearchHits hits = search.getHits();
        System.out.println(hits);
        for (SearchHit h:hits) {
            System.out.println(h.getSourceAsString());
        }

聚合查询

查询最大值

        //聚合查询
        SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        MaxAggregationBuilder field = AggregationBuilders.max("maxAge").field("age");

        searchSourceBuilder.aggregation(field);
        searchRequest.source(searchSourceBuilder);


        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        System.out.println(search);

分组查询

       SearchRequest searchRequest = new SearchRequest();
        searchRequest.indices("user");
        SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
        TermsAggregationBuilder field = AggregationBuilders.terms("groupAge").field("age");

        searchSourceBuilder.aggregation(field);
        searchRequest.source(searchSourceBuilder);


        SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        System.out.println(search);