ElasticSearch入门之HTTP和JavaAPI操作
ElasticSearch
1. 安装
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华为镜像下载，本次下载的是windows下的7.8.0版本。
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下载完成之后解压：
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启动：双击bin/elasticsearch.bat文件。
如图所示：9300为内部集群通信端口，9200为RESful端口。
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访问http://localhost:9200/，出现如下界面，就表示访问成功。
2. 数据格式
es是面向文档型数据库，一条数据就是一个文档。
- 与关系型数据库概念的类比：
需要注意的是在7.6版本之后types的概念已经被删除了。
3. HTTP操作es
3.1 索引
- 创建索引：发送put请求到es，
- 获取索引：发送get请求到es
- 获取全部索引：发送get请求到
http://localhost:9200/_cat/indices?v
- 删除索引：发送delete请求
3.2 文档操作
- 创建文档(类比关系性数据库表数据)：向es发送post请求
http://localhost:9200/new_index/_doc
这里使用postman了，apipost不行。。
- 携带id新建文档：
http://localhost:9200/new_index/_doc/1001
- 文档查询：发送get请求即可
- 查询当前索引下所有文档：
http://localhost:9200/new_index/_doc/_search
- 全量数据修改文档：使用幂等性的put请求，只传要修改的参数。
http://localhost:9200/new_index/_doc/1001
- 局部更新文档：需要使用post请求；
http://localhost:9200/new_index/_update/1001
- 删除文档：发送delete请求，
http://localhost:9200/new_index/_doc/1001
3.3 文档高级查询
- 查询category为分类的全部文档：
http://localhost:9200/new_index/_search?q=category:分类
- 使用json方式查询与上方相同的内容。
- 分页查询：
- 过滤响应数据：
- 数据排序：
- 多条件查询——同时成立
- 多条件查询——满足任意一个
- 范围查询：
- 全文检索：es会将文字拆解成一个个的关键字，然后进行倒排索引的匹配，匹配其中条件的数据全部列出来（类似于模糊查询）。
- 完全匹配：
- 高亮查询：
- 聚合查询：
- 映射关系：在创建文档时指定。
4. Java API操作es
4.1 搭建环境
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引入依赖：
<dependencies> <dependency> <groupId>org.elasticsearchgroupId> <artifactId>elasticsearchartifactId> <version>7.8.0version> dependency> <dependency> <groupId>org.elasticsearch.clientgroupId> <artifactId>elasticsearch-rest-high-level-clientartifactId> <version>7.8.0version> dependency> <dependency> <groupId>org.apache.logging.log4jgroupId> <artifactId>log4j-apiartifactId> <version>2.17.2version> dependency> <dependency> <groupId>org.apache.logging.log4jgroupId> <artifactId>log4j-coreartifactId> <version>2.13.3version> dependency> <dependency> <groupId>com.fasterxml.jackson.coregroupId> <artifactId>jackson-databindartifactId> <version>2.13.1version> dependency> <dependency> <groupId>junitgroupId> <artifactId>junitartifactId> <version>4.13version> dependency> <dependency> <groupId>org.projectlombokgroupId> <artifactId>lombokartifactId> <version>1.18.24version> dependency> dependencies> -
构建es操作客户端
/** * @Description es客户端 * @date 2022/7/14 9:33 */ public class ES_Client { private static final String HOST_NAME = "localhost"; private static final Integer PORT = 9200; private static final String SCHEME = "http"; public static void main(String[] args) throws IOException { // 创建es客户端 RestHighLevelClient esClient = new RestHighLevelClient(RestClient.builder(new HttpHost(HOST_NAME,PORT,SCHEME))); // 关闭es客户端 esClient.close(); }
4.2 封装连接工具类
/**
* @Description
* @date 2022/7/14 14:42
*/
public class ConnESUtil {
private static final String HOST_NAME = "localhost";
private static final Integer PORT = 9200;
private static final String SCHEME = "http";
public static RestHighLevelClient getEsClient(){
return new RestHighLevelClient(RestClient.builder(new HttpHost(HOST_NAME, PORT, SCHEME)));
}
}
4.3 索引操作
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创建索引：
/** * 创建索引 */ private static void createIndices() throws IOException { CreateIndexRequest user = new CreateIndexRequest("user_2"); CreateIndexResponse response = esClient.indices().create(user, RequestOptions.DEFAULT); System.out.println(response.isAcknowledged()); } -
查询索引：
/** * 查询索引信息 * @throws IOException */ private static void getIndices() throws IOException { GetIndexRequest request = new GetIndexRequest("user_2"); GetIndexResponse response = ES_Client.esClient.indices().get(request, RequestOptions.DEFAULT); // 获取当前索引的信息 System.out.println(response.getAliases()); System.out.println(response.getMappings()); System.out.println(response.getSettings() ); } -
删除索引：
/** * 删除索引 * @throws IOException */ private static void delIndices() throws IOException { DeleteIndexRequest request = new DeleteIndexRequest("user_2"); AcknowledgedResponse response = esClient.indices().delete(request, RequestOptions.DEFAULT); System.out.println(response.isAcknowledged()); }
4.4 文档基本操作
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封装数据模型：
@Data @ToString @AllArgsConstructor @NoArgsConstructor public class User3 { private String name; private String sex; private Integer age; } -
新增文档：
/** * 添加文档 * @throws IOException */ private static void addDoc() throws IOException { IndexRequest request = new IndexRequest(); // 指定索引名称 和 当前文档的id request.index("user3").id("1001"); User3 user = new User3("a", "男" ,30); // 对象转json ObjectMapper mapper = new ObjectMapper(); String jsonUser = mapper.writeValueAsString(user); // 指定请求传入数据 和 数据类型 request.source(jsonUser, XContentType.JSON); // 创建 IndexResponse res = esClient.index(request, RequestOptions.DEFAULT); System.out.println(res.getResult()); }添加之后去查询，可以看到新增的数据：
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修改文档：
/** * 修改文档 * @throws IOException */ private static void updateDoc() throws IOException { UpdateRequest request = new UpdateRequest(); // 指定要修改的索引 和 id request.index("user3").id("1001"); // 传入要修改的数据 request.doc(XContentType.JSON, "sex", "女"); UpdateResponse res = esClient.update(request, RequestOptions.DEFAULT); System.out.println(res.getResult()); }
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查询文档：
/** * 查询文档 * @throws IOException */ private static void getDoc() throws IOException { GetRequest request = new GetRequest(); // 指定索引 和 id request.index("user3").id("1001"); GetResponse res = esClient.get(request, RequestOptions.DEFAULT); System.out.println(res.getSourceAsString()); }
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删除文档：
/** * 删除文档 * @throws IOException */ private static void delDoc() throws IOException { DeleteRequest request = new DeleteRequest(); // 指定索引 和 id request.index("user3").id("1001"); DeleteResponse res = esClient.delete(request, RequestOptions.DEFAULT); }
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批量新增：
/** * 批量文档新增 * @throws IOException */ private static void addDocs() throws IOException { BulkRequest request = new BulkRequest(); // 添加多个请求，同时发送 // 这里的 source 方法，必须要使用 v ： k 的形式传入一个或者多个，不能使用对象转json字符串方法。 request.add(new IndexRequest().index("user3").id("1002").source(XContentType.JSON, "name", "b")); request.add(new IndexRequest().index("user3").id("1003").source(XContentType.JSON, "name", "c")); request.add(new IndexRequest().index("user3").id("1004").source(XContentType.JSON, "name", "d")); BulkResponse res = esClient.bulk(request, RequestOptions.DEFAULT); // 查看耗时 System.out.println(res.getTook()); } -
批量删除：
/** * 批量删除文档 * @throws IOException */ private static void delDocs() throws IOException { BulkRequest request = new BulkRequest(); request.add(new DeleteRequest().index("user3").id("1002")); request.add(new DeleteRequest().index("user3").id("1003")); request.add(new DeleteRequest().index("user3").id("1004")); BulkResponse res = esClient.bulk(request, RequestOptions.DEFAULT); // 查看耗时 System.out.println(res.getTook()); }
4.5 文档高级查询
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数据准备，以上方批量插入的形式插入多条可供测试的数据到es：
BulkRequest request = new BulkRequest(); // 添加多个请求，同时发送 // 这里的 source 方法，必须要使用 v ： k 的形式传入一个或者多个，不能使用对象转json字符串方法。 request.add(new IndexRequest().index("user3").id("1001").source(XContentType.JSON, "name", "zhangsan", "age", "30", "sex", "男")); request.add(new IndexRequest().index("user3").id("1002").source(XContentType.JSON, "name", "lisi", "age", "30", "sex", "女")); request.add(new IndexRequest().index("user3").id("1003").source(XContentType.JSON, "name", "wangwu", "age", "40", "sex", "男")); request.add(new IndexRequest().index("user3").id("1004").source(XContentType.JSON, "name", "wangwu1", "age", "40", "sex", "女")); request.add(new IndexRequest().index("user3").id("1005").source(XContentType.JSON, "name", "wangwu2", "age", "50", "sex", "男")); request.add(new IndexRequest().index("user3").id("1006").source(XContentType.JSON, "name", "wangwu3", "age", "50", "sex", "男")); BulkResponse res = esClient.bulk(request, RequestOptions.DEFAULT); // 查看耗时 System.out.println(res.getTook()); -
查询索引下全部文档：
/** * 查询指定索引下全部文档信息 * @throws IOException */ private static void list() throws IOException { SearchRequest request = new SearchRequest(); request.indices("user3"); // 构建查询参数 request.source(new SearchSourceBuilder().query(QueryBuilders.matchAllQuery())); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
根据传入参数查询：
/** * 根据查询文档信息 * @param age * @throws IOException */ private static void getByAge(String age) throws IOException { SearchRequest request = new SearchRequest(); request.indices("user3"); // 构建查询参数 request.source(new SearchSourceBuilder().query(QueryBuilders.termQuery("age", age))); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
分页查询：
/** * 分页查询 * @param page * @param size * @throws IOException */ private static void list(Integer page, Integer size) throws IOException { SearchRequest request = new SearchRequest(); request.indices("user3"); // 构建查询参数 SearchSourceBuilder query = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()); query.from(page); query.size(size); request.source(query); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
排序查出的数据：
/** * 排序查询 * @param sortedBy * @param order * @throws IOException */ private static void list(String sortedBy, SortOrder order) throws IOException{ SearchRequest request = new SearchRequest(); request.indices("user3"); // 构建查询参数 SearchSourceBuilder query = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()); query.sort(sortedBy, order); request.source(query); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
过滤字段：
/** * 过滤字段 * @param excludes 要排除的字段 * @param includes 包含的字段 * @throws IOException */ private static void filterCol(String[] excludes, String[] includes) throws IOException{ SearchRequest request = new SearchRequest(); request.indices("user3"); // 构建查询参数 SearchSourceBuilder query = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()); query.fetchSource(excludes, includes); request.source(query); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
多条件查询：
/** * 多字段组合查询 * @throws IOException */ private static void getByInfo() throws IOException { SearchRequest request = new SearchRequest(); request.indices("user3"); SearchSourceBuilder builder = new SearchSourceBuilder(); BoolQueryBuilder boolQuery = QueryBuilders.boolQuery(); boolQuery.must(QueryBuilders.matchQuery("age", "30")); boolQuery.must(QueryBuilders.matchQuery("sex", "男")); // boolQuery.should(QueryBuilders.matchQuery("age", "30")); // boolQuery.should(QueryBuilders.matchQuery("sex", "男")); // 构建查询参数 builder.query(boolQuery); request.source(builder); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
范围查询：
/** * 范围查询 * @throws IOException */ private static void getByRange() throws IOException{ SearchRequest request = new SearchRequest(); request.indices("user3"); SearchSourceBuilder builder = new SearchSourceBuilder(); RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery("age"); builder.query(rangeQuery); rangeQuery.gt("30"); request.source(builder); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
模糊查询：
/** * 模糊查询 * @throws IOException */ private static void getLike() throws IOException{ SearchRequest request = new SearchRequest(); request.indices("user3"); SearchSourceBuilder builder = new SearchSourceBuilder(); FuzzyQueryBuilder fuzzyQuery = QueryBuilders.fuzzyQuery("name","wangwu") .fuzziness(Fuzziness.ONE); //指定模糊查询精度：相差小于等于几个 builder.query(fuzzyQuery); request.source(builder); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); // 遍历返回信息 for (SearchHit hit : hits) { System.out.println(hit.getSourceAsString()); } } -
高亮查询：
/** * 高亮查询 * @throws IOException */ private static void getHighLight() throws IOException{ SearchRequest request = new SearchRequest(); request.indices("user3"); SearchSourceBuilder builder = new SearchSourceBuilder(); TermQueryBuilder queryBuilder = QueryBuilders .termQuery("name","zhangsan");// 指定高亮字段和对应值 // 高亮builder HighlightBuilder highlightBuilder = new HighlightBuilder(); // 指定前缀和后缀标签 highlightBuilder.preTags(""); highlightBuilder.postTags(""); // 指定高亮字段 highlightBuilder.field("name"); builder.highlighter(highlightBuilder); builder.query(queryBuilder); request.source(builder); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); System.out.println(res); }
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聚合查询（获取最大值）：数据都在res对象中
/** * 获取最大年龄数据 * @throws IOException */ private static void getMax() throws IOException{ SearchRequest request = new SearchRequest(); request.indices("user3"); SearchSourceBuilder builder = new SearchSourceBuilder(); // 指定聚合要求的内容 和 字段 AggregationBuilder aggregationBuilder = AggregationBuilders.max("maxAge").field("age"); builder.aggregation(aggregationBuilder); request.source(builder); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); System.out.println(res); }
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分组查询：
/** * 分组查询 * @throws IOException */ private static void getGroupByAge() throws IOException{ SearchRequest request = new SearchRequest(); request.indices("user3"); SearchSourceBuilder builder = new SearchSourceBuilder(); // 指定聚合要求的内容 和 字段 AggregationBuilder aggregationBuilder = AggregationBuilders.terms("count").field("age"); builder.aggregation(aggregationBuilder); request.source(builder); // 执行查询 SearchResponse res = esClient.search(request, RequestOptions.DEFAULT); // 返回数据 SearchHits hits = res.getHits(); // 查看总条数 System.out.println(hits.getTotalHits()); System.out.println(res); }