Elasticsearch简单学习

1、依赖的导入

<!--ES依赖-->
<dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-high-level-client</artifactId>
</dependency>

2、客户端链接

RestHighLevelClient client = new RestHighLevelClient(RestClient.builder(HttpHost.create("http://localhost:9200")));

3、索引库的相关操作

1、索引库的创建

@Test
void createTestIndex() throws IOException {/*创建索引库*///1.创建Request对象，索引库名称必须为小写字母CreateIndexRequest request = new CreateIndexRequest("test_index");String source = "{\n" +"        \"mappings\":{\n" +"        \"properties\":{\n" +"            \"id\":{\n" +"                \"type\":\"integer\"\n" +"            },\n" +"            \"name\":{\n" +"                \"type\":\"text\",\n" +"                \"analyzer\":\"ik_max_word\"\n" +"            },\n" +"            \"age\":{\n" +"                \"type\":\"integer\"\n" +"            },\n" +"            \"sex\":{\n" +"                \"type\":\"keyword\"\n" +"            },\n" +"            \"bossId\":{\n" +"                \"type\":\"integer\"\n" +"            },\n" +"            \"departmentId\":{\n" +"                \"type\":\"integer\"\n" +"            }\n" +"        }\n" +"    }\n" +"}";//2.准备请求的参数：DSL语句request.source(source, XContentType.JSON);//3.发请求client.indices().create(request, RequestOptions.DEFAULT);
}

2、判断索引库是否存在

@Test
void existsTestIndex() throws IOException {/*判断索引库是否存在*///1.创建Request对象，名称必须为小写字母GetIndexRequest request = new GetIndexRequest("test_index");//2.发请求boolean is = client.indices().exists(request, RequestOptions.DEFAULT);System.out.println(is);
}

3、删除索引库

@Test
void deleteTestIndex() throws IOException {/*删除索引库*///1.创建Request对象，名称必须为小写字母DeleteIndexRequest request = new DeleteIndexRequest("test_index");//2.发请求client.indices().delete(request, RequestOptions.DEFAULT);
}

4、文档的操作

1、创建文档

@Test
void createDocTest() throws IOException {//从数据库中获取数据对象Employee employee = employeeMapper.selectAllById(1);//1. 创建Request对象IndexRequest request = new IndexRequest("test_index").id(employee.getId().toString());//2.准备json文档String source = JSON.toJSONString(employee);//2.1准备json文档request.source(source, XContentType.JSON);//3.发请求client.index(request, RequestOptions.DEFAULT);
}

2、获取指定的文档

@Test
void getDocTest() throws IOException {//1.创建Request对象GetRequest request = new GetRequest("test_index","1");//2.发请求，得到结果GetResponse response = client.get(request, RequestOptions.DEFAULT);//3.解析结果String json = response.getSourceAsString();System.out.println(json);Employee employee = JSON.parseObject(json, Employee.class);System.out.println(employee);
}

3、更新文档

@Test
void updateDocTest() throws IOException {//1.创建Request对象UpdateRequest request = new UpdateRequest("test_index","1");//2.准备DSL语句request.doc("age",18);//3.发请求client.update(request,RequestOptions.DEFAULT);
}

4、删除文档

@Test
void deleteDocTest() throws IOException {//1.创建Request对象DeleteRequest request = new DeleteRequest("test_index","1");//2.发请求client.delete(request,RequestOptions.DEFAULT);
}

5、批量操作（创建）

@Test
void batchCreateDocTest() throws IOException {//1.创建Request对象BulkRequest request = new BulkRequest();//2.准备DSL语句，批量增加文档List<Employee> employees = employeeMapper.selectAll();for(Employee e : employees){request.add(new IndexRequest("test_index").id(e.getId().toString()).source(JSON.toJSONString(e),XContentType.JSON));}//3.发请求client.bulk(request,RequestOptions.DEFAULT);
}

5、搜索文档

1、分词查询-查询全部

@Test
void matchAllTest() throws IOException {  //分词查询//1.准备RequestSearchRequest request = new SearchRequest("test_index");//2.组织DSL参数request.source() // 查询全部.query(QueryBuilders.matchAllQuery());//3.发送请求SearchResponse response = client.search(request,RequestOptions.DEFAULT);//4.解析结果SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("总共有：" + total + "条数据");//4.2获取文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历数组for(SearchHit h : hits){String json = h.getSourceAsString();Employee employee = JSON.parseObject(json, Employee.class);System.out.println(employee);}
}

2、分词查询-指定字段

@Test
void matchQueryTest() throws IOException { //分词查询//1.准备RequestSearchRequest request = new SearchRequest("test_index");//2.组织DSL参数request.source() //查询指定字段的值，也可以指定多个字段 .multiMatchQuery().query(QueryBuilders.matchQuery("name","晨"));//3.发送请求SearchResponse response = client.search(request,RequestOptions.DEFAULT);//4.解析结果SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("总共有：" + total + "条数据");//4.2获取文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历数组for(SearchHit h : hits){String json = h.getSourceAsString();Employee employee = JSON.parseObject(json, Employee.class);System.out.println(employee);}
}

3、精确查询

@Test
void termQueryTest() throws IOException {  //精确查询//1.准备RequestSearchRequest request = new SearchRequest("test_index");//2.组织DSL参数request.source() //精确查询只能查询 非text（分词字段），如果查询分词字段，则自动采用模糊分词查询.query(QueryBuilders.termQuery("age","33"));//3.发送请求SearchResponse response = client.search(request,RequestOptions.DEFAULT);//4.解析结果SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("总共有：" + total + "条数据");//4.2获取文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历数组for(SearchHit h : hits){String json = h.getSourceAsString();Employee employee = JSON.parseObject(json, Employee.class);System.out.println(employee);}
}

4、范围查询

@Test
void rangeQueryTest() throws IOException {  //范围查询//1.准备RequestSearchRequest request = new SearchRequest("test_index");//2.组织DSL参数request.source() //范围查询，gte：大于等于，lte：小于等于，gt：大于，lt：小于.query(QueryBuilders.rangeQuery("age").gte(30).lte(35));//3.发送请求SearchResponse response = client.search(request,RequestOptions.DEFAULT);//4.解析结果SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("总共有：" + total + "条数据");//4.2获取文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历数组for(SearchHit h : hits){String json = h.getSourceAsString();Employee employee = JSON.parseObject(json, Employee.class);System.out.println(employee);}
}

5、复合查询

@Test
void boolQueryTest() throws IOException {  //复合查询//1.准备RequestSearchRequest request = new SearchRequest("test_index");//2.1创建复合查询对象BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();//2.2添加查询条件boolQuery.must(QueryBuilders.matchQuery("name","雨"));boolQuery.filter(QueryBuilders.rangeQuery("age").gte(20).lte(35));//2.3组织DSL参数request.source().query(boolQuery);//3.发送请求SearchResponse response = client.search(request,RequestOptions.DEFAULT);//4.解析结果SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("总共有：" + total + "条数据");//4.2获取文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历数组for(SearchHit h : hits){String json = h.getSourceAsString();Employee employee = JSON.parseObject(json, Employee.class);System.out.println(employee);}
}

6、分页排序查询

@Test
void pageSortQueryTest() throws IOException {  //分页、排序查询// 页码，每页大小int page = 3,size = 10;//1.准备RequestSearchRequest request = new SearchRequest("test_index");//2组织DSL参数request.source().from((page-1)*size) // 包含form，(page-1)*size，是前端传过来的页码和每页条数.size(size).sort("id", SortOrder.ASC).query(QueryBuilders.matchAllQuery());//3.发送请求SearchResponse response = client.search(request,RequestOptions.DEFAULT);//4.解析结果SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("总共有：" + total + "条数据");//4.2获取文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历数组for(SearchHit h : hits){String json = h.getSourceAsString();Employee employee = JSON.parseObject(json, Employee.class);System.out.println(employee);}
}

6、高亮查询

@Test
void highLightQueryTest() throws IOException {  //高亮查询//1.准备RequestSearchRequest request = new SearchRequest("test_index");//2组织DSL参数request.source().highlighter(new HighlightBuilder() //高亮显示.field("name") //字段名.requireFieldMatch(false) // 是否与查询字段匹配) // 用的默认标签 <em></em>.query(QueryBuilders.matchQuery("name","晨"));//3.发送请求SearchResponse response = client.search(request,RequestOptions.DEFAULT);//4.解析结果SearchHits searchHits = response.getHits();//4.1获取总条数long total = searchHits.getTotalHits().value;System.out.println("总共有：" + total + "条数据");//4.2获取文档数组SearchHit[] hits = searchHits.getHits();//4.3遍历数组for(SearchHit h : hits){String json = h.getSourceAsString();Employee employee = JSON.parseObject(json, Employee.class);// 高亮显示，因为每条数据都是带有 晨 的，所以每条数据都有一个HighlightField用于替换HighlightField name = h.getHighlightFields().get("name");//替换employee.setName(name.getFragments()[0].toString());System.out.println(employee);}
}