操作ES有很多种方式，而官方推荐的是使用Java REST Client 本例使用的ES版本：7.6.2

ES提供了两个JAVA REST client 版本

Java Low Level REST Client: 低级别的REST客户端，通过http与集群交互，用户需自己编组请求JSON串，及解析响应JSON串。兼容所有ES版本。Java High Level REST Client: 高级别的REST客户端，基于低级别的REST客户端，增加了编组请求JSON串、解析响应JSON串等相关api。使用的版本需要保持和ES服务端的版本一致，否则会有版本问题。

Java Low Level REST Client 说明

特点、maven 引入、使用介绍： https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-low.html API doc：https://artifacts.elastic.co/javadoc/org/elasticsearch/client/elasticsearch-rest-client/6.2.4/index.html

Java High Level REST Client 说明

从6.0.0开始加入的，目的是以java面向对象的方式来进行请求、响应处理。 每个API 支持 同步/异步 两种方式，同步方法直接返回一个结果对象。异步的方法以async为后缀，通过listener参数来通知结果。 高级java REST 客户端依赖Elasticsearch core project

兼容性说明： 依赖 java1.8 和 Elasticsearch core project 请使用与服务端ES版本一致的客户端版本

官方文档

https://www.elastic.co/guide/en/elasticsearch/client/java-rest/7.9/java-rest-low.html

一、Maven依赖

<!-- https://mvnrepository.com/artifact/org.elasticsearch.client/elasticsearch-rest-high-level-client --> <dependency> <groupId>org.elasticsearch.client</groupId> <artifactId>elasticsearch-rest-high-level-client</artifactId> <version>7.6.2</version> </dependency>

二、配置

@Configuration public class RestClientConfig extends AbstractElasticsearchConfiguration { @Override public RestHighLevelClient elasticsearchClient() { ClientConfiguration clientConfiguration = ClientConfiguration.builder() .connectedTo("localhost:9200") .build(); return RestClients.create(clientConfiguration).rest(); } }

三、操作Elasticsearch

1.创建索引

package com.example; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.elasticsearch.action.admin.indices.alias.Alias; 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.RestHighLevelClient; import org.elasticsearch.common.settings.Settings; import org.elasticsearch.common.xcontent.XContentType; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.io.IOException; @SpringBootTest public class IndexCreateTest { @Autowired private RestHighLevelClient restHighLevelClient; private static Logger logger = LogManager.getRootLogger(); /** * 创建索引 * * @throws IOException */ @Test public void indexCreate() { try { // 1、创建索引twitter 参数：索引名 twitter CreateIndexRequest request = new CreateIndexRequest("twitter"); // 2、设置索引的settings request.settings(Settings.builder() // 分片数 // .put("index.number_of_shards", 3) // 副本数 // .put("index.number_of_replicas", 2) .put("analysis.analyzer.default.tokenizer", "ik_max_word") // 默认分词器 ); // 3、设置索引的mapping request.mapping("_doc", "{\n" + " \"properties\":{\n" + " \"id\":{\n" + " \"type\":\"long\",\n" + " \"store\":true\n" + " },\n" + " \"username\":{\n" + " \"type\":\"text\",\n" + " \"store\":true,\n" + " \"analyzer\":\"ik_max_word\"\n" + " },\n" + " \"email\":{\n" + " \"type\":\"text\",\n" + " \"store\":true,\n" + " \"analyzer\":\"ik_max_word\"\n" + " }\n" + " }\n" + "}", XContentType.JSON); // 4、 设置索引的别名 request.alias(new Alias("账户信息")); // 5、 发送请求 // 5.1 同步方式发送请求 CreateIndexResponse createIndexResponse = restHighLevelClient.indices() .create(request, RequestOptions.DEFAULT); // 6、处理响应 boolean acknowledged = createIndexResponse.isAcknowledged(); boolean shardsAcknowledged = createIndexResponse .isShardsAcknowledged(); logger.info("acknowledged = " + acknowledged); logger.info("shardsAcknowledged = " + shardsAcknowledged); // 5.1 异步方式发送请求 /*ActionListener<CreateIndexResponse> listener = new ActionListener<CreateIndexResponse>() { @Override public void onResponse( CreateIndexResponse createIndexResponse) { // 6、处理响应 boolean acknowledged = createIndexResponse.isAcknowledged(); boolean shardsAcknowledged = createIndexResponse .isShardsAcknowledged(); logger.info("acknowledged = " + acknowledged); logger.info( "shardsAcknowledged = " + shardsAcknowledged); } @Override public void onFailure(Exception e) { logger.info("创建索引异常：" + e.getMessage()); } }; client.indices().createAsync(request, listener); */ } catch (IOException e) { logger.error(e); } } }

2.修改type的mapping

/** * 自定义json字符串方式设置Mapping * * @throws IOException */ @Test public void putMappingRequest() { try { PutMappingRequest request = new PutMappingRequest("twitter"); request.type("_doc"); request.source( "{\n" + " \"properties\":{\n" + " \"id\":{\n" + " \"type\":\"long\",\n" + " \"store\":true\n" + " },\n" + " \"username\":{\n" + " \"type\":\"text\",\n" + " \"store\":true,\n" + " \"analyzer\":\"ik_max_word\"\n" + " },\n" + " \"email\":{\n" + " \"type\":\"text\",\n" + " \"store\":true,\n" + " \"analyzer\":\"ik_max_word\"\n" + " },\n" + " \"age\":{\n" + " \"type\":\"long\",\n" + " \"store\":true\n" + " }\n" + " }\n" + "}", XContentType.JSON); restHighLevelClient.indices().putMapping(request, RequestOptions.DEFAULT); } catch (IOException e) { System.out.println(e); } }

3.往索引里面放入文档数据

package com.example; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.elasticsearch.ElasticsearchException; import org.elasticsearch.action.DocWriteResponse; import org.elasticsearch.action.index.IndexRequest; import org.elasticsearch.action.index.IndexResponse; import org.elasticsearch.action.support.replication.ReplicationResponse; import org.elasticsearch.client.RequestOptions; import org.elasticsearch.client.RestHighLevelClient; import org.elasticsearch.common.xcontent.XContentType; import org.elasticsearch.rest.RestStatus; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.io.IOException; @SpringBootTest public class IndexDocumentTest { @Autowired private RestHighLevelClient restHighLevelClient; private static Logger logger = LogManager.getRootLogger(); /** * 索引文档，即往索引里面放入文档数据.类似于数据库里面向表里面插入一行数据，一行数据就是一个文档 * * @throws IOException */ @Test public void indexDocument() { try { // 1、创建索引请求 IndexRequest request = new IndexRequest( "twitter", //索引 "_doc", // mapping type "1"); //文档id // 2、准备文档数据 // 方式一：直接给JSON串 String jsonString = "{" + "\"id\":\"1\"," + "\"username\":\"JonssonYan\"," + "\"email\":\"yz808@outlook.com\"" + "}"; request.source(jsonString, XContentType.JSON); // 方式二：以map对象来表示文档 // Map<String, Object> jsonMap = new HashMap<>(); // jsonMap.put("id", "1"); // jsonMap.put("messageId", "20201008"); // jsonMap.put("content", "trying out Elasticsearch"); // request.source(jsonMap); // 方式三：用XContentBuilder来构建文档 // XContentBuilder builder = XContentFactory.jsonBuilder(); // builder.startObject(); // { // builder.field("id", "1"); // builder.field("messageId", "20201008"); // builder.field("content", "trying out Elasticsearch"); // } // builder.endObject(); // request.source(builder); // 方式四：直接用key-value对给出 // request.source("id", "1", // "messageId", "20201008", // "content", "trying out Elasticsearch", // 3、其他的一些可选设置 // 设置routing值 // request.routing("routing"); // 设置主分片等待时长 // request.timeout(TimeValue.timeValueSeconds(1)); // 设置重刷新策略 // request.setRefreshPolicy("wait_for"); // 设置版本号 // request.version(2); // 操作类别 // request.opType(DocWriteRequest.OpType.CREATE); //4、发送请求 IndexResponse indexResponse = null; try { // 同步方式 indexResponse = restHighLevelClient.index(request, RequestOptions.DEFAULT); } catch (ElasticsearchException e) { // 捕获，并处理异常 //判断是否版本冲突、create但文档已存在冲突 if (e.status() == RestStatus.CONFLICT) { System.out.println("冲突了，请在此写冲突处理逻辑！" + e.getDetailedMessage()); } System.out.println("索引异常"); } //5、处理响应 if (indexResponse != null) { String index = indexResponse.getIndex(); String type = indexResponse.getType(); String id = indexResponse.getId(); long version = indexResponse.getVersion(); if (indexResponse.getResult() == DocWriteResponse.Result.CREATED) { System.out.println("新增文档成功，处理逻辑代码写到这里。"); } else if (indexResponse.getResult() == DocWriteResponse.Result.UPDATED) { System.out.println("修改文档成功，处理逻辑代码写到这里。"); } // 分片处理信息 ReplicationResponse.ShardInfo shardInfo = indexResponse.getShardInfo(); if (shardInfo.getTotal() != shardInfo.getSuccessful()) { } // 如果有分片副本失败，可以获得失败原因信息 if (shardInfo.getFailed() > 0) { for (ReplicationResponse.ShardInfo.Failure failure : shardInfo.getFailures()) { String reason = failure.reason(); System.out.println("副本失败原因：" + reason); } } } } catch (IOException e) { logger.error(e); } } }

4.获取文档数据

package com.example; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.elasticsearch.ElasticsearchException; import org.elasticsearch.action.get.GetRequest; import org.elasticsearch.action.get.GetResponse; import org.elasticsearch.client.RequestOptions; import org.elasticsearch.client.RestHighLevelClient; import org.elasticsearch.common.Strings; import org.elasticsearch.rest.RestStatus; import org.elasticsearch.search.fetch.subphase.FetchSourceContext; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.io.IOException; import java.util.Map; @SpringBootTest public class GetDocumentTest { @Autowired private RestHighLevelClient restHighLevelClient; private static Logger logger = LogManager.getRootLogger(); @Test public void getDocument() { try { // 1、创建获取文档请求 GetRequest request = new GetRequest( "twitter", //索引 "_doc", // mapping type "1"); //文档id // 2、可选的设置 //request.routing("routing"); //request.version(2); //request.fetchSourceContext(new FetchSourceContext(false)); //是否获取_source字段 //选择返回的字段 String[] includes = new String[]{"id", "username", "email"}; String[] excludes = Strings.EMPTY_ARRAY; FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes); request.fetchSourceContext(fetchSourceContext); //也可写成这样 /*String[] includes = Strings.EMPTY_ARRAY; String[] excludes = new String[]{"message"}; FetchSourceContext fetchSourceContext = new FetchSourceContext(true, includes, excludes); request.fetchSourceContext(fetchSourceContext);*/ // 取stored字段 /*request.storedFields("message"); GetResponse getResponse = client.get(request); String message = getResponse.getField("message").getValue();*/ //3、发送请求 GetResponse getResponse = null; try { // 同步请求 getResponse = restHighLevelClient.get(request, RequestOptions.DEFAULT); } catch (ElasticsearchException e) { if (e.status() == RestStatus.NOT_FOUND) { logger.info("没有找到该id的文档"); } if (e.status() == RestStatus.CONFLICT) { logger.info("获取时版本冲突了，请在此写冲突处理逻辑！"); } logger.info("获取文档异常" + e); } //4、处理响应 if (getResponse != null) { String index = getResponse.getIndex(); String type = getResponse.getType(); String id = getResponse.getId(); if (getResponse.isExists()) { // 文档存在 long version = getResponse.getVersion(); String sourceAsString = getResponse.getSourceAsString(); //结果取成 String Map<String, Object> sourceAsMap = getResponse.getSourceAsMap(); // 结果取成Map byte[] sourceAsBytes = getResponse.getSourceAsBytes(); //结果取成字节数组 logger.info("index:" + index + " type:" + type + " id:" + id); logger.info(sourceAsString); } else { logger.info("没有找到该id的文档"); } } //异步方式发送获取文档请求 /* ActionListener<GetResponse> listener = new ActionListener<GetResponse>() { @Override public void onResponse(GetResponse getResponse) { } @Override public void onFailure(Exception e) { } }; client.getAsync(request, listener); */ } catch (IOException e) { logger.error(e); } } }

5.搜索数据

package com.example; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.apache.lucene.search.TotalHits; import org.elasticsearch.action.search.SearchRequest; import org.elasticsearch.action.search.SearchResponse; import org.elasticsearch.action.search.ShardSearchFailure; import org.elasticsearch.client.RequestOptions; import org.elasticsearch.client.RestHighLevelClient; import org.elasticsearch.common.unit.TimeValue; import org.elasticsearch.index.query.QueryBuilders; import org.elasticsearch.rest.RestStatus; import org.elasticsearch.search.SearchHit; import org.elasticsearch.search.SearchHits; import org.elasticsearch.search.builder.SearchSourceBuilder; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.io.IOException; import java.util.Map; import java.util.concurrent.TimeUnit; @SpringBootTest public class SearchTest { @Autowired private RestHighLevelClient restHighLevelClient; private static Logger logger = LogManager.getRootLogger(); @Test public void search() { try { // 1、创建search请求 //SearchRequest searchRequest = new SearchRequest(); SearchRequest searchRequest = new SearchRequest("twitter"); searchRequest.types("_doc"); // 2、用SearchSourceBuilder来构造查询请求体 ,请仔细查看它的方法，构造各种查询的方法都在这。 SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); // 构造QueryBuilder /*QueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("username", "JonssonYan") // 对匹配查询启用模糊匹配 .fuzziness(Fuzziness.AUTO) // 在匹配查询中设置前缀长度选项 .prefixLength(3) // 设置最大扩展选项以控制查询的模糊过程 .maxExpansions(10); sourceBuilder.query(matchQueryBuilder);*/ sourceBuilder.query(QueryBuilders.termQuery("email", "yz808@outlook.com")); // 设置from确定结果索引以开始搜索的选项。预设为0。 sourceBuilder.from(0); // 设置size用于确定要返回的搜索命中次数的选项。默认为10 sourceBuilder.size(10); // 设置一个可选的超时时间，以控制允许搜索的时间。 sourceBuilder.timeout(new TimeValue(60, TimeUnit.SECONDS)); //是否返回_source字段 //sourceBuilder.fetchSource(false); //设置返回哪些字段 /*String[] includeFields = new String[] {"username", "email", "innerObject.*"}; String[] excludeFields = new String[] {"_type"}; sourceBuilder.fetchSource(includeFields, excludeFields);*/ //指定排序 //sourceBuilder.sort(new ScoreSortBuilder().order(SortOrder.DESC)); //sourceBuilder.sort(new FieldSortBuilder("_uid").order(SortOrder.ASC)); // 设置返回 profile //sourceBuilder.profile(true); //将请求体加入到请求中 searchRequest.source(sourceBuilder); // 可选的设置 //searchRequest.routing("routing"); // 高亮设置 /*HighlightBuilder highlightBuilder = new HighlightBuilder(); HighlightBuilder.Field highlightTitle = new HighlightBuilder.Field("username"); highlightTitle.highlighterType("text"); highlightBuilder.field(highlightTitle); HighlightBuilder.Field highlightUser = new HighlightBuilder.Field("email"); highlightBuilder.field(highlightUser); sourceBuilder.highlighter(highlightBuilder);*/ //加入聚合 /*TermsAggregationBuilder aggregation = AggregationBuilders.terms("by_company") .field("company.keyword"); aggregation.subAggregation(AggregationBuilders.avg("average_age") .field("age")); sourceBuilder.aggregation(aggregation);*/ //做查询建议 /*SuggestionBuilder termSuggestionBuilder = SuggestBuilders.termSuggestion("user").text("kmichy"); SuggestBuilder suggestBuilder = new SuggestBuilder(); suggestBuilder.addSuggestion("suggest_user", termSuggestionBuilder); sourceBuilder.suggest(suggestBuilder);*/ //3、发送请求 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //4、处理响应 //搜索结果状态信息 RestStatus status = searchResponse.status(); TimeValue took = searchResponse.getTook(); Boolean terminatedEarly = searchResponse.isTerminatedEarly(); boolean timedOut = searchResponse.isTimedOut(); //分片搜索情况 int totalShards = searchResponse.getTotalShards(); int successfulShards = searchResponse.getSuccessfulShards(); int failedShards = searchResponse.getFailedShards(); for (ShardSearchFailure failure : searchResponse.getShardFailures()) { // failures should be handled here } //处理搜索命中文档结果 SearchHits hits = searchResponse.getHits(); TotalHits totalHits = hits.getTotalHits(); float maxScore = hits.getMaxScore(); SearchHit[] searchHits = hits.getHits(); for (SearchHit hit : searchHits) { // do something with the SearchHit String index = hit.getIndex(); String type = hit.getType(); String id = hit.getId(); float score = hit.getScore(); //取_source字段值 String sourceAsString = hit.getSourceAsString(); //取成json串 Map<String, Object> sourceAsMap = hit.getSourceAsMap(); // 取成map对象 //从map中取字段值 /* String documentTitle = (String) sourceAsMap.get("title"); List<Object> users = (List<Object>) sourceAsMap.get("user"); Map<String, Object> innerObject = (Map<String, Object>) sourceAsMap.get("innerObject"); */ logger.info("index:" + index + " type:" + type + " id:" + id); logger.info(sourceAsString); //取高亮结果 /*Map<String, HighlightField> highlightFields = hit.getHighlightFields(); HighlightField highlight = highlightFields.get("title"); Text[] fragments = highlight.fragments(); String fragmentString = fragments[0].string();*/ } // 获取聚合结果 /* Aggregations aggregations = searchResponse.getAggregations(); Terms byCompanyAggregation = aggregations.get("by_company"); Bucket elasticBucket = byCompanyAggregation.getBucketByKey("Elastic"); Avg averageAge = elasticBucket.getAggregations().get("average_age"); double avg = averageAge.getValue(); */ // 获取建议结果 /*Suggest suggest = searchResponse.getSuggest(); TermSuggestion termSuggestion = suggest.getSuggestion("suggest_user"); for (TermSuggestion.Entry entry : termSuggestion.getEntries()) { for (TermSuggestion.Entry.Option option : entry) { String suggestText = option.getText().string(); } } */ //异步方式发送获查询请求 /* ActionListener<SearchResponse> listener = new ActionListener<SearchResponse>() { @Override public void onResponse(SearchResponse getResponse) { //结果获取 } @Override public void onFailure(Exception e) { //失败处理 } }; client.searchAsync(searchRequest, listener); */ } catch (IOException e) { logger.error(e); } } }

6.高亮

package com.example; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.apache.lucene.search.TotalHits; import org.elasticsearch.action.search.SearchRequest; import org.elasticsearch.action.search.SearchResponse; import org.elasticsearch.client.RequestOptions; import org.elasticsearch.client.RestHighLevelClient; import org.elasticsearch.common.text.Text; import org.elasticsearch.index.query.QueryBuilder; import org.elasticsearch.index.query.QueryBuilders; import org.elasticsearch.rest.RestStatus; import org.elasticsearch.search.SearchHit; import org.elasticsearch.search.SearchHits; import org.elasticsearch.search.builder.SearchSourceBuilder; import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder; import org.elasticsearch.search.fetch.subphase.highlight.HighlightField; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.io.IOException; import java.util.Map; @SpringBootTest public class HighlightTest { @Autowired private RestHighLevelClient restHighLevelClient; private static Logger logger = LogManager.getRootLogger(); @Test public void highlight() { try { // 1、创建search请求 SearchRequest searchRequest = new SearchRequest("twitter"); // 2、用SearchSourceBuilder来构造查询请求体 ,请仔细查看它的方法，构造各种查询的方法都在这。 SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); //构造QueryBuilder QueryBuilder matchQueryBuilder = QueryBuilders.matchQuery("username", "JonssonYan"); sourceBuilder.query(matchQueryBuilder); //分页设置 /*sourceBuilder.from(0); sourceBuilder.size(5); ;*/ // 高亮设置 HighlightBuilder highlightBuilder = new HighlightBuilder(); highlightBuilder.requireFieldMatch(false).field("username").field("email") .preTags("<strong>").postTags("</strong>"); //不同字段可有不同设置，如不同标签 /*HighlightBuilder.Field highlightTitle = new HighlightBuilder.Field("title"); highlightTitle.preTags("<strong>").postTags("</strong>"); highlightBuilder.field(highlightTitle); HighlightBuilder.Field highlightContent = new HighlightBuilder.Field("content"); highlightContent.preTags("<b>").postTags("</b>"); highlightBuilder.field(highlightContent).requireFieldMatch(false);*/ sourceBuilder.highlighter(highlightBuilder); searchRequest.source(sourceBuilder); //3、发送请求 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //4、处理响应 if (RestStatus.OK.equals(searchResponse.status())) { //处理搜索命中文档结果 SearchHits hits = searchResponse.getHits(); TotalHits totalHits = hits.getTotalHits(); SearchHit[] searchHits = hits.getHits(); for (SearchHit hit : searchHits) { String index = hit.getIndex(); String type = hit.getType(); String id = hit.getId(); float score = hit.getScore(); //取_source字段值 //String sourceAsString = hit.getSourceAsString(); //取成json串 Map<String, Object> sourceAsMap = hit.getSourceAsMap(); // 取成map对象 //从map中取字段值 /*String title = (String) sourceAsMap.get("title"); String content = (String) sourceAsMap.get("content"); */ logger.info("index:" + index + " type:" + type + " id:" + id); logger.info("sourceMap : " + sourceAsMap); //取高亮结果 Map<String, HighlightField> highlightFields = hit.getHighlightFields(); HighlightField highlight = highlightFields.get("username"); if (highlight != null) { Text[] fragments = highlight.fragments(); //多值的字段会有多个值 if (fragments != null) { String fragmentString = fragments[0].string(); logger.info("username highlight : " + fragmentString); //可用高亮字符串替换上面sourceAsMap中的对应字段返回到上一级调用 //sourceAsMap.put("title", fragmentString); } } highlight = highlightFields.get("email"); if (highlight != null) { Text[] fragments = highlight.fragments(); //多值的字段会有多个值 if (fragments != null) { String fragmentString = fragments[0].string(); logger.info("email highlight : " + fragmentString); //可用高亮字符串替换上面sourceAsMap中的对应字段返回到上一级调用 //sourceAsMap.put("content", fragmentString); } } } } } catch (IOException e) { logger.error(e); } } }

7.查询建议

词项建议拼写检查，检查用户的拼写是否错误，如果有错给用户推荐正确的词，appel->apple

package com.example; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.elasticsearch.action.search.SearchRequest; import org.elasticsearch.action.search.SearchResponse; import org.elasticsearch.client.RequestOptions; import org.elasticsearch.client.RestHighLevelClient; import org.elasticsearch.rest.RestStatus; import org.elasticsearch.search.builder.SearchSourceBuilder; import org.elasticsearch.search.suggest.Suggest; import org.elasticsearch.search.suggest.SuggestBuilder; import org.elasticsearch.search.suggest.SuggestBuilders; import org.elasticsearch.search.suggest.SuggestionBuilder; import org.elasticsearch.search.suggest.term.TermSuggestion; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.io.IOException; @SpringBootTest public class SuggestTest { @Autowired private RestHighLevelClient restHighLevelClient; private static Logger logger = LogManager.getRootLogger(); /** * 词项建议拼写检查，检查用户的拼写是否错误，如果有错给用户推荐正确的词，appel->apple */ @Test public void termSuggest() { try { // 1、创建search请求 //SearchRequest searchRequest = new SearchRequest(); SearchRequest searchRequest = new SearchRequest("twitter"); // 2、用SearchSourceBuilder来构造查询请求体 ,请仔细查看它的方法，构造各种查询的方法都在这。 SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); sourceBuilder.size(0); //做查询建议 //词项建议 SuggestionBuilder termSuggestionBuilder = SuggestBuilders.termSuggestion("username").text("JonssonYa"); SuggestBuilder suggestBuilder = new SuggestBuilder(); suggestBuilder.addSuggestion("suggest_user", termSuggestionBuilder); sourceBuilder.suggest(suggestBuilder); searchRequest.source(sourceBuilder); //3、发送请求 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //4、处理响应 //搜索结果状态信息 if (RestStatus.OK.equals(searchResponse.status())) { // 获取建议结果 Suggest suggest = searchResponse.getSuggest(); TermSuggestion termSuggestion = suggest.getSuggestion("suggest_user"); for (TermSuggestion.Entry entry : termSuggestion.getEntries()) { logger.info("text: " + entry.getText().string()); for (TermSuggestion.Entry.Option option : entry) { String suggestText = option.getText().string(); logger.info(" suggest option : " + suggestText); } } } } catch (IOException e) { e.printStackTrace(); } } }

自动补全，根据用户的输入联想到可能的词或者短语

8.聚合分析

package com.example; import org.apache.logging.log4j.LogManager; import org.apache.logging.log4j.Logger; import org.elasticsearch.action.search.SearchRequest; import org.elasticsearch.action.search.SearchResponse; import org.elasticsearch.client.RequestOptions; import org.elasticsearch.client.RestHighLevelClient; import org.elasticsearch.rest.RestStatus; import org.elasticsearch.search.aggregations.AggregationBuilders; import org.elasticsearch.search.aggregations.Aggregations; import org.elasticsearch.search.aggregations.BucketOrder; import org.elasticsearch.search.aggregations.bucket.terms.Terms; import org.elasticsearch.search.aggregations.bucket.terms.TermsAggregationBuilder; import org.elasticsearch.search.aggregations.metrics.Avg; import org.elasticsearch.search.builder.SearchSourceBuilder; import org.junit.jupiter.api.Test; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.test.context.SpringBootTest; import java.io.IOException; @SpringBootTest public class AggregationTest { @Autowired private RestHighLevelClient restHighLevelClient; private static Logger logger = LogManager.getRootLogger(); @Test public void aggregation() { try { // 1、创建search请求 //SearchRequest searchRequest = new SearchRequest(); SearchRequest searchRequest = new SearchRequest("twitter"); // 2、用SearchSourceBuilder来构造查询请求体 ,请仔细查看它的方法，构造各种查询的方法都在这。 SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); sourceBuilder.size(0); //加入聚合 //字段值项分组聚合 TermsAggregationBuilder aggregation = AggregationBuilders.terms("by_age") .field("age").order(BucketOrder.aggregation("average_balance", true)); //计算每组的平均balance指标 aggregation.subAggregation(AggregationBuilders.avg("average_balance") .field("balance")); sourceBuilder.aggregation(aggregation); searchRequest.source(sourceBuilder); //3、发送请求 SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); //4、处理响应 //搜索结果状态信息 if (RestStatus.OK.equals(searchResponse.status())) { // 获取聚合结果 Aggregations aggregations = searchResponse.getAggregations(); Terms byAgeAggregation = aggregations.get("by_age"); logger.info("aggregation by_age 结果"); logger.info("docCountError: " + byAgeAggregation.getDocCountError()); logger.info("sumOfOtherDocCounts: " + byAgeAggregation.getSumOfOtherDocCounts()); logger.info("------------------------------------"); for (Terms.Bucket buck : byAgeAggregation.getBuckets()) { logger.info("key: " + buck.getKeyAsNumber()); logger.info("docCount: " + buck.getDocCount()); logger.info("docCountError: " + buck.getDocCountError()); //取子聚合 Avg averageBalance = buck.getAggregations().get("average_balance"); logger.info("average_balance: " + averageBalance.getValue()); logger.info("------------------------------------"); } //直接用key 来去分组 /*Bucket elasticBucket = byCompanyAggregation.getBucketByKey("24"); Avg averageAge = elasticBucket.getAggregations().get("average_age"); double avg = averageAge.getValue();*/ } } catch (IOException e) { logger.error(e); } } }

各种查询对应的QueryBuilder： https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-query-builders.html 各种聚合对应的AggregationBuilder： https://www.elastic.co/guide/en/elasticsearch/client/java-rest/current/java-rest-high-aggregation-builders.html