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jsonObjectMapper 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);