環境：springboot2.4.12 + elasticsearch7.8.0dfn28資訊網——每日最新資訊28at.com

      Elasticsearch是一種開源的、分布式的、實時的搜索和分析引擎。它允許你存儲，搜索和分析大量數據，通常用于為網站或應用程序提供強大的搜索功能。dfn28資訊網——每日最新資訊28at.com

      Java API是Elasticsearch提供的官方客戶端，它允許Java開發者輕松地與Elasticsearch服務器進行交互。下面是一些關于如何使用Java API來調用Elasticsearch的常用方法。dfn28資訊網——每日最新資訊28at.com

注意：這里為了方便使用springboot項目（避免還要單獨引用其它包）dfn28資訊網——每日最新資訊28at.com

相關依賴

<dependency>  <groupId>org.springframework.boot</groupId>  <artifactId>spring-boot-starter-web</artifactId></dependency><dependency>  <groupId>org.elasticsearch</groupId>  <artifactId>elasticsearch</artifactId>  <version>7.8.0</version><!--$NO-MVN-MAN-VER$--></dependency><dependency>  <groupId>org.elasticsearch.client</groupId>  <artifactId>elasticsearch-rest-high-level-client</artifactId>  <version>7.8.0</version><!--$NO-MVN-MAN-VER$--></dependency>

索引操作

高級別的Rest客戶端對象dfn28資訊網——每日最新資訊28at.com

private static RestHighLevelClient client =   new RestHighLevelClient(RestClient.builder(    new HttpHost("localhost", 9200, "http"))) ;

1. 創建索引

public static void createIndex(String index) throws Exception {  CreateIndexRequest request = new CreateIndexRequest(index) ;  CreateIndexResponse response = client.indices().create(request, RequestOptions.DEFAULT) ;  boolean ack = response.isAcknowledged() ;  System.out.println("ack = " + ack) ;}

2. 查看索引

public static void viewIndex(String index) throws Exception {  GetIndexRequest request = new GetIndexRequest(index) ;  GetIndexResponse response = client.indices().get(request, RequestOptions.DEFAULT) ;  System.out.println("aliases: " + response.getAliases() + "/n"    + "mappings: " + response.getMappings() + "/n"    + "settings: " + response.getSettings()) ;}

3. 刪除索引

public static void deleteIndex(String index) throws Exception {  DeleteIndexRequest request = new DeleteIndexRequest(index) ;  AcknowledgedResponse response = client.indices().delete(request, RequestOptions.DEFAULT) ;  System.out.println("ack: " + response.isAcknowledged()) ;}

文檔操作

private static RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(new HttpHost("localhost", 9200, "http"))) ;

1. 創建文檔

public static void createDoc(String index, Users users) throws Exception {  IndexRequest request = new IndexRequest() ;  // 設置索引及唯一標識  request.index(index).id("1001") ;  ObjectMapper objectMapper = new ObjectMapper() ;  String jsonString = objectMapper.writeValueAsString(users) ;  // 添加文檔數據及數據格式  request.source(jsonString, XContentType.JSON) ;  IndexResponse response = client.index(request, RequestOptions.DEFAULT) ;  System.out.println("_index: " + response.getIndex() + "/n"      + "_id: " + response.getId() + "/n"      + "_result: " + response.getResult()) ;}

2. 更新文檔

public static void updateDoc(String index, String id) throws Exception {  UpdateRequest request = new UpdateRequest() ;  // 配置修改參數  request.index(index).id(id) ;  Map<String, Object> source = new HashMap<>() ;  source.put("sex", "女") ;  request.doc(source, XContentType.JSON) ;  UpdateResponse response = client.update(request, RequestOptions.DEFAULT) ;  System.out.println("_index: " + response.getIndex() + "/n"      + "_id: " + response.getId() + "/n"      + "_result: " + response.getResult()) ;}

3. 查詢文檔

public static void viewDoc(String index, String id) throws Exception {  GetRequest request = new GetRequest().index(index).id(id) ;  GetResponse response = client.get(request, RequestOptions.DEFAULT) ;  System.out.println("_index: " + response.getIndex() + "/n"      + "_type: " + response.getType() + "/n"      + "_id: " + response.getId() + "/n"      + "source: " + response.getSourceAsString()) ;}

4. 刪除文檔

public static void deleteIndex(String index, String id) throws Exception {  DeleteRequest request = new DeleteRequest().index(index).id(id) ;  DeleteResponse response = client.delete(request, RequestOptions.DEFAULT) ;  System.out.println(response.toString()) ;}

5. 批量操作

public static void batchOperator(String index) throws Exception {  BulkRequest request = new BulkRequest() ;  request.add(new IndexRequest().index(index).id("1002").source(XContentType.JSON, "name","老六", "sex", "男", "age", 20)) ;  request.add(new IndexRequest().index(index).id("1003").source(XContentType.JSON, "name","外網", "sex", "女", "age", 10)) ;  request.add(new IndexRequest().index(index).id("1004").source(XContentType.JSON, "name","莉莉", "sex", "女", "age", 35)) ;  BulkResponse response = client.bulk(request, RequestOptions.DEFAULT) ;  System.out.println("took: " + response.getTook() + "/n"      + "items: " + new ObjectMapper().writeValueAsString(response.getItems())) ;}

6. 高級查詢

public static void highSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.query(QueryBuilders.matchAllQuery()) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString()) ;  }}

7. term精確查詢

public static void highTermSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.query(QueryBuilders.termQuery("age", "20")) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString()) ;  }}

8. 分頁查詢

public static void highPagingSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.query(QueryBuilders.matchAllQuery()) ;  builder.from(1) ;  builder.size(2) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString()) ;  }}

9. 分頁&排序查詢

public static void highPagingAndSortSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.query(QueryBuilders.matchAllQuery()) ;  builder.from(0) ;  builder.size(20) ;  builder.sort("age", SortOrder.ASC) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString()) ;  }}

10. 分頁&排序&過濾字段查詢

public static void highPagingAndSortAndFilterFieldSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.query(QueryBuilders.matchAllQuery()) ;  builder.from(0) ;  builder.size(20) ;  builder.sort("age", SortOrder.ASC) ;  String[] includes = {"name"} ;  String[] excludes = {} ;  builder.fetchSource(includes, excludes) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString()) ;  }}

11. 范圍查詢

public static void highBoolSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.query(QueryBuilders.matchAllQuery()) ;  builder.from(0) ;  builder.size(20) ;  builder.sort("age", SortOrder.ASC) ;  RangeQueryBuilder rangeBuilder = QueryBuilders.rangeQuery("age");  rangeBuilder.gte(15) ;  rangeBuilder.lte(30) ;  builder.query(rangeBuilder) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString()) ;  }}

12. 高亮查詢

public static void highHighLightSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.query(QueryBuilders.matchQuery("name", "莉莉")) ;  HighlightBuilder highLightBuilder = new HighlightBuilder() ;  highLightBuilder.preTags("<font color='red'>") ;  highLightBuilder.postTags("</font>") ;  highLightBuilder.field("name") ;  builder.highlighter(highLightBuilder) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString() + "/n"        + "highlight: " + hit.getHighlightFields()) ;  }}

13. 聚合查詢

public static void highAggsSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.aggregation(AggregationBuilders.avg("avg_age").field("age")) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString())  ;  }  System.out.println(((ParsedAvg)response.getAggregations().iterator().next()).getValue()) ;}

14. 分組統計

public static void highGroupSearch(String index) throws Exception {  SearchRequest request = new SearchRequest().indices(index) ;  SearchSourceBuilder builder = new SearchSourceBuilder() ;  builder.aggregation(AggregationBuilders.terms("age_groupby").field("age")) ;  request.source(builder) ;  SearchResponse response = client.search(request, RequestOptions.DEFAULT) ;  SearchHits hits = response.getHits() ;  System.out.println("took: " + response.getTook() + "/n"      + "timeout: " + response.isTimedOut() + "/n"      + "total: " + hits.getTotalHits() + "/n"      + "MaxScore: " + hits.getMaxScore()) ;  for (SearchHit hit : hits) {    System.out.println(hit.getSourceAsString()) ;  }  System.out.println(response) ;}

完畢！??！dfn28資訊網——每日最新資訊28at.com

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