Java操作ElasticSearch，java类加载机制面试

3、删除索引

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//删除索引

public static void Index_Delete() throws Exception{

//创建ES客户端

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”,9200,“http”))

);

// 查询索引

DeleteIndexRequest request = new DeleteIndexRequest(“user”);

AcknowledgedResponse response = esClient.indices().delete(request, RequestOptions.DEFAULT);

//响应状态

System.out.println(response.isAcknowledged());

//关闭ES客户端

esClient.close();

}

4、创建文档（插入数据）

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public static void main(String[] args) throws Exception {

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”, 9200, “http”))

);

// 插入数据

IndexRequest request = new IndexRequest();

request.index(“user”).id(“1001”);

User user = new User();

user.setName(“zhangsan”);

user.setAge(30);

user.setSex(“男”);

// 向ES插入数据，必须将数据转换位JSON格式

ObjectMapper mapper = new ObjectMapper();

String userJson = mapper.writevalueAsString(user);

request.source(userJson, XContentType.JSON);

IndexResponse response = esClient.index(request, RequestOptions.DEFAULT);

System.out.println(response.getResult());

esClient.close();

}

批量插入数据：

public static void main(String[] args) throws Exception {

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”, 9200, “http”))

);

// 批量插入数据

BulkRequest request = new BulkRequest();

request.add(new IndexRequest().index(“user”).id(“1001”).source(XContentType.JSON, “name”, “zhangsan”, “age”,30,“sex”,“男”));

request.add(new IndexRequest().index(“user”).id(“1002”).source(XContentType.JSON, “name”, “lisi”, “age”,30,“sex”,“女”));

request.add(new IndexRequest().index(“user”).id(“1003”).source(XContentType.JSON, “name”, “wangwu”, “age”,40,“sex”,“男”));

request.add(new IndexRequest().index(“user”).id(“1004”).source(XContentType.JSON, “name”, “wangwu1”, “age”,40,“sex”,“女”));

request.add(new IndexRequest().index(“user”).id(“1005”).source(XContentType.JSON, “name”, “wangwu2”, “age”,50,“sex”,“男”));

request.add(new IndexRequest().index(“user”).id(“1006”).source(XContentType.JSON, “name”, “wangwu3”, “age”,50,“sex”,“男”));

request.add(new IndexRequest().index(“user”).id(“1007”).source(XContentType.JSON, “name”, “wangwu44”, “age”,60,“sex”,“男”));

request.add(new IndexRequest().index(“user”).id(“1008”).source(XContentType.JSON, “name”, “wangwu555”, “age”,60,“sex”,“男”));

request.add(new IndexRequest().index(“user”).id(“1009”).source(XContentType.JSON, “name”, “wangwu66666”, “age”,60,“sex”,“男”));

BulkResponse response = esClient.bulk(request, RequestOptions.DEFAULT);

System.out.println(response.getTook());

System.out.println(response.getItems());

esClient.close();

}

5、修改文档

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将上面的数据中的性别改成女

public static void main(String[] args) throws Exception {

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”, 9200, “http”))

);

// 修改数据

UpdateRequest request = new UpdateRequest();

request.index(“user”).id(“1001”);

request.doc(XContentType.JSON, “sex”, “女”);

UpdateResponse response = esClient.update(request, RequestOptions.DEFAULT);

System.out.println(response.getResult());

esClient.close();

}

6、普通的查询文档

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public static void main(String[] args) throws Exception {

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”, 9200, “http”))

);

// 查询数据

GetRequest request = new GetRequest();

request.index(“user”).id(“1001”);

GetResponse response = esClient.get(request, RequestOptions.DEFAULT);

System.out.println(response.getSourceAsString());

esClient.close();

}

7、删除文档

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public static void main(String[] args) throws Exception {

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”, 9200, “http”))

);

DeleteRequest request = new DeleteRequest();

request.index(“user”).id(“1001”);

DeleteResponse response = esClient.delete(request, RequestOptions.DEFAULT);

System.out.println(response.toString());

esClient.close();

}

批量删除：

public static void main(String[] args) throws Exception {

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”, 9200, “http”))

);

// 批量删除数据

BulkRequest request = new BulkRequest();

request.add(new DeleteRequest().index(“user”).id(“1001”));

request.add(new DeleteRequest().index(“user”).id(“1002”));

request.add(new DeleteRequest().index(“user”).id(“1003”));

BulkResponse response = esClient.bulk(request, RequestOptions.DEFAULT);

System.out.println(response.getTook());

System.out.println(response.getItems());

esClient.close();

}

8、高级查询文档

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public static void main(String[] args) throws Exception {

RestHighLevelClient esClient = new RestHighLevelClient(

RestClient.builder(new HttpHost(“localhost”, 9200, “http”))

);

// 1. 查询索引中全部的数据

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// request.source(new SearchSourceBuilder().query(QueryBuilders.matchAllQuery()));

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// 2. 条件查询 : termQuery

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// request.source(new SearchSourceBuilder().query(QueryBuilders.termQuery(“age”, 30)));

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// 3. 分页查询

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// SearchSourceBuilder builder = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());

// // (当前页码-1)*每页显示数据条数

// builder.from(2);

// builder.size(2);

// request.source(builder);

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// // 4. 查询排序

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// SearchSourceBuilder builder = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());

// //

// builder.sort(“age”, SortOrder.DESC);

// request.source(builder);

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// // 5. 过滤字段

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// SearchSourceBuilder builder = new SearchSourceBuilder().query(QueryBuilders.matchAllQuery());

// //

// String[] excludes = {“age”};

// String[] includes = {};

// builder.fetchSource(includes, excludes);

// request.source(builder);

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// // 6. 组合查询

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// SearchSourceBuilder builder = new SearchSourceBuilder();

// BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();

// //boolQueryBuilder.must(QueryBuilders.matchQuery(“age”, 30));

// //boolQueryBuilder.must(QueryBuilders.matchQuery(“sex”, “男”));

// //boolQueryBuilder.mustNot(QueryBuilders.matchQuery(“sex”, “男”));

// boolQueryBuilder.should(QueryBuilders.matchQuery(“age”, 30));

// boolQueryBuilder.should(QueryBuilders.matchQuery(“age”, 40));

// builder.query(boolQueryBuilder);

// request.source(builder);

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// // 7. 范围查询

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// SearchSourceBuilder builder = new SearchSourceBuilder();

// RangeQueryBuilder rangeQuery = QueryBuilders.rangeQuery(“age”);

// rangeQuery.gte(30);

// rangeQuery.lt(50);

// builder.query(rangeQuery);

// request.source(builder);

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// 8. 模糊查询

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// SearchSourceBuilder builder = new SearchSourceBuilder();

// builder.query(QueryBuilders.fuzzyQuery(“name”, “wangwu”).fuzziness(Fuzziness.TWO));

// request.source(builder);

// SearchResponse response = esClient.search(request, RequestOptions.DEFAULT);

// SearchHits hits = response.getHits();

// System.out.println(hits.getTotalHits());

// System.out.println(response.getTook());

// for ( SearchHit hit : hits ) {

// System.out.println(hit.getSourceAsString());

// }

// // 9. 高亮查询

// SearchRequest request = new SearchRequest();

// request.indices(“user”);

// SearchSourceBuilder builder = new SearchSourceBuilder();