1. ElasticSearch
1.1 倒排索引
1.2 ElasticSearch和Mysql对比
1.3 RestClient操作
导入依赖
<dependency><groupId>org.elasticsearch.client</groupId><artifactId>elasticsearch-rest-high-level-client</artifactId><version>7.15.0</version></dependency>
并设置
<elasticsearch.version>7.15.0</elasticsearch.version>
添加ElasticSearch配置
@Configuration
public class ElasticSearchConfig {@Beanpublic RestHighLevelClient restHighLevelClient(){RestHighLevelClient client=new RestHighLevelClient(RestClient.builder(new HttpHost("127.0.0.1",9200,"http")));return client;}
}
索引的创建,判断是否存在,删除
CreateIndexRequest createIndexRequest=new CreateIndexRequest("test");restHighLevelClient.indices().create(createIndexRequest, RequestOptions.DEFAULT);//判断某个索引库是否存在GetIndexRequest getIndexRequest=new GetIndexRequest("test");boolean exists = restHighLevelClient.indices().exists(getIndexRequest, RequestOptions.DEFAULT);System.out.println(exists);//删除某个索引库DeleteIndexRequest deleteIndexRequest=new DeleteIndexRequest("test");restHighLevelClient.indices().delete(deleteIndexRequest,RequestOptions.DEFAULT);
添加文档
IndexRequest in = new IndexRequest("test").id("1").source("{\n" +" \"username\":\"admin\",\n" +" \"password\":\"admin\"\n" +"}", XContentType.JSON);restHighLevelClient.index(in,RequestOptions.DEFAULT);
查找文档
GetRequest getRequest=new GetRequest("test","1");GetResponse getResponse = restHighLevelClient.get(getRequest, RequestOptions.DEFAULT);System.out.println(getResponse.getSourceAsString());
更新文档
//全量更新,再次写入id一样的文档,就会删除旧文档,添加新文档IndexRequest in = new IndexRequest("test").id("1").source("{\n" +" \"username\":\"admin\",\n" +" \"password\":\"helloworld\"\n" +"}", XContentType.JSON);restHighLevelClient.index(in,RequestOptions.DEFAULT);UpdateRequest updateRequest=new UpdateRequest("test","1");updateRequest.doc("password","hello");restHighLevelClient.update(updateRequest,RequestOptions.DEFAULT);
删除文档
DeleteRequest deleteRequest=new DeleteRequest("test","1");restHighLevelClient.delete(deleteRequest,RequestOptions.DEFAULT);
批量导入文档
BulkRequest bulkRequest=new BulkRequest();bulkRequest.add(new IndexRequest("test").id("2").source("{\n" +" \"username\":\"hello\",\n" +" \"password\":\"hello\"\n" +"}",XContentType.JSON));bulkRequest.add(new IndexRequest("test").id("3").source("{\n" +" \"username\":\"world\",\n" +" \"password\":\"world\"\n" +"}",XContentType.JSON));restHighLevelClient.bulk(bulkRequest,RequestOptions.DEFAULT);