中间件：ElasticSearch组件RestHighLevelClient用法详解
本文源码：GitHub·点这里 || GitEE·点这里
一、基础API简介
1、RestHighLevelClient
RestHighLevelClient的API作为ElasticSearch备受推荐的客户端组件，其封装系统操作ES的方法，包括索引结构管理，数据增删改查管理，常用查询方法，并且可以结合原生ES查询原生语法，功能十分强大。
在使用RestHighLevelClient的语法时，通常涉及上面几个方面，在掌握基础用法之上可以根据业务特点进行一些自定义封装，这样可以更优雅的解决业务需求。
2、核心依赖
使用RestHighLevelClient需要依赖rest-high-level-client包，和ES相关基础依赖。
<dependency> <groupId>org.elasticsearch</groupId> <artifactId>elasticsearch</artifactId></dependency><dependency> <groupId>org.elasticsearch.client</groupId> <artifactId>elasticsearch-rest-client</artifactId></dependency><dependency> <groupId>org.elasticsearch.client</groupId> <artifactId>elasticsearch-rest-high-level-client</artifactId></dependency>
二、索引管理
这里不做过多描述，注意一点：因为ES的数据结构特点，所以不需要索引更新方法，新的字段在更新数据时直接写入即可，不需要提前更新索引结构。
@Servicepublic class EsIndexOperation { @Resource private RestHighLevelClient client ; private final RequestOptions options = RequestOptions.DEFAULT; /** * 判断索引是否存在 */ public boolean checkIndex (String index) { try { return client.indices().exists(new GetIndexRequest(index), options); } catch (IOException e) { e.printStackTrace(); } return Boolean.FALSE ; } /** * 创建索引 */ public boolean createIndex (String indexName ,Map<String, Object> columnMap){ try { if(!checkIndex(indexName)){ CreateIndexRequest request = new CreateIndexRequest(indexName); if (columnMap != null && columnMap.size()>0) { Map<String, Object> source = new HashMap<>(); source.put("properties", columnMap); request.mapping(source); } this.client.indices().create(request, options); return Boolean.TRUE ; } } catch (IOException e) { e.printStackTrace(); } return Boolean.FALSE; } /** * 删除索引 */ public boolean deleteIndex(String indexName) { try { if(checkIndex(indexName)){ DeleteIndexRequest request = new DeleteIndexRequest(indexName); AcknowledgedResponse response = client.indices().delete(request, options); return response.isAcknowledged(); } } catch (Exception e) { e.printStackTrace(); } return Boolean.FALSE; }}
三、数据管理
这里在更新数据时，可以直接修改索引结构，在dataMap中放进新的字段即可。
@Servicepublic class EsDataOperation { @Resource private RestHighLevelClient client ; private final RequestOptions options = RequestOptions.DEFAULT; /** * 写入数据 */ public boolean insert (String indexName, Map<String,Object> dataMap){ try { BulkRequest request = new BulkRequest(); request.add(new IndexRequest(indexName,"doc").id(dataMap.remove("id").toString()) .opType("create").source(dataMap,XContentType.JSON)); this.client.bulk(request, options); return Boolean.TRUE ; } catch (Exception e){ e.printStackTrace(); } return Boolean.FALSE; } /** * 批量写入数据 */ public boolean batchInsert (String indexName, List<Map<String,Object>> userIndexList){ try { BulkRequest request = new BulkRequest(); for (Map<String,Object> dataMap:userIndexList){ request.add(new IndexRequest(indexName,"doc").id(dataMap.remove("id").toString()) .opType("create").source(dataMap,XContentType.JSON)); } this.client.bulk(request, options); return Boolean.TRUE ; } catch (Exception e){ e.printStackTrace(); } return Boolean.FALSE; } /** * 更新数据，可以直接修改索引结构 */ public boolean update (String indexName, Map<String,Object> dataMap){ try { UpdateRequest updateRequest = new UpdateRequest(indexName,"doc", dataMap.remove("id").toString()); updateRequest.setRefreshPolicy(WriteRequest.RefreshPolicy.IMMEDIATE); updateRequest.doc(dataMap) ; this.client.update(updateRequest, options); return Boolean.TRUE ; } catch (Exception e){ e.printStackTrace(); } return Boolean.FALSE; } /** * 删除数据 */ public boolean delete (String indexName, String id){ try { DeleteRequest deleteRequest = new DeleteRequest(indexName,"doc", id); this.client.delete(deleteRequest, options); return Boolean.TRUE ; } catch (Exception e){ e.printStackTrace(); } return Boolean.FALSE; }}
四、查询操作
注意：查询总数的CountRequest语法，SearchRequest查询结果中数据转换语法，分页查询中需要指定偏移位置和分页大小。
@Servicepublic class EsQueryOperation { @Resource private RestHighLevelClient client ; private final RequestOptions options = RequestOptions.DEFAULT; /** * 查询总数 */ public Long count (String indexName){ // 指定创建时间 BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery(); queryBuilder.must(QueryBuilders.termQuery("createTime", 1611378102795L)); SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); sourceBuilder.query(queryBuilder); CountRequest countRequest = new CountRequest(indexName); countRequest.source(sourceBuilder); try { CountResponse countResponse = client.count(countRequest, options); return countResponse.getCount(); } catch (Exception e) { e.printStackTrace(); } return 0L; } /** * 查询集合 */ public List<Map<String,Object>> list (String indexName) { // 查询条件,指定时间并过滤指定字段值 SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); BoolQueryBuilder queryBuilder = QueryBuilders.boolQuery(); queryBuilder.must(QueryBuilders.termQuery("createTime", 1611378102795L)); queryBuilder.mustNot(QueryBuilders.termQuery("name","北京-李四")); sourceBuilder.query(queryBuilder); SearchRequest searchRequest = new SearchRequest(indexName); searchRequest.source(sourceBuilder); try { SearchResponse searchResp = client.search(searchRequest, options); List<Map<String,Object>> data = new ArrayList<>() ; SearchHit[] searchHitArr = searchResp.getHits().getHits(); for (SearchHit searchHit:searchHitArr){ Map<String,Object> temp = searchHit.getSourceAsMap(); temp.put("id",searchHit.getId()) ; data.add(temp); } return data; } catch (Exception e) { e.printStackTrace(); } return null ; } /** * 分页查询 */ public List<Map<String,Object>> page (String indexName,Integer offset,Integer size) { // 查询条件,指定时间并过滤指定字段值 SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); sourceBuilder.from(offset); sourceBuilder.size(size); sourceBuilder.sort("createTime", SortOrder.DESC); SearchRequest searchRequest = new SearchRequest(indexName); searchRequest.source(sourceBuilder); try { SearchResponse searchResp = client.search(searchRequest, options); List<Map<String,Object>> data = new ArrayList<>() ; SearchHit[] searchHitArr = searchResp.getHits().getHits(); for (SearchHit searchHit:searchHitArr){ Map<String,Object> temp = searchHit.getSourceAsMap(); temp.put("id",searchHit.getId()) ; data.add(temp); } return data; } catch (Exception e) { e.printStackTrace(); } return null ; }}
五、排序方式
排序除了常规的指定字段升序降序规则之外，还可以基于原生的脚本语法，基于自定义规则排序让一些特定的数据沉底或者置顶。
@Servicepublic class EsSortOperation { @Resource private RestHighLevelClient client ; private final RequestOptions options = RequestOptions.DEFAULT; /** * 排序规则 */ public List<Map<String,Object>> sort (String indexName) { // 先升序时间，在倒序年龄 SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); sourceBuilder.sort("createTime", SortOrder.ASC); sourceBuilder.sort("age",SortOrder.DESC) ; SearchRequest searchRequest = new SearchRequest(indexName); searchRequest.source(sourceBuilder); try { SearchResponse searchResp = client.search(searchRequest, options); List<Map<String,Object>> data = new ArrayList<>() ; SearchHit[] searchHitArr = searchResp.getHits().getHits(); for (SearchHit searchHit:searchHitArr){ Map<String,Object> temp = searchHit.getSourceAsMap(); temp.put("id",searchHit.getId()) ; data.add(temp); } return data; } catch (Exception e) { e.printStackTrace(); } return null ; } /** * 自定义排序规则 */ public List<Map<String,Object>> defSort (String indexName) { // 指定置换顺序的规则 // [age 12-->60]\[age 19-->10]\[age 13-->30]\[age 18-->40],age其他值忽略为1 Script script = new Script("def _ageSort = doc['age'].value == 12?60:" + "(doc['age'].value == 19?10:" + "(doc['age'].value == 13?30:" + "(doc['age'].value == 18?40:1)));" + "_ageSort;"); ScriptSortBuilder sortBuilder = SortBuilders.scriptSort(script,ScriptSortBuilder.ScriptSortType.NUMBER); sortBuilder.order(SortOrder.ASC); SearchSourceBuilder sourceBuilder = new SearchSourceBuilder(); sourceBuilder.sort(sortBuilder); SearchRequest searchRequest = new SearchRequest(indexName); searchRequest.source(sourceBuilder); try { SearchResponse searchResp = client.search(searchRequest, options); List<Map<String,Object>> data = new ArrayList<>() ; SearchHit[] searchHitArr = searchResp.getHits().getHits(); for (SearchHit searchHit:searchHitArr){ Map<String,Object> temp = searchHit.getSourceAsMap(); temp.put("id",searchHit.getId()) ; data.add(temp); } return data; } catch (Exception e) { e.printStackTrace(); } return null ; }}
六、源代码地址
GitHub·地址https://github.com/cicadasmile/data-manage-parentGitEE·地址https://gitee.com/cicadasmile/data-manage-parent
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