Elasticsearch JDBC案例介紹

The best elasticsearch highlevel java rest api-----bboss       

Elasticsearch  6.3之後的版本能夠經過jdbc操做es，該功能還在不斷的完善當中，本文介紹es jdbc使用方法。

1.首先在工程中導入es jdbc maven座標：

導入elasticsearch jdbc驅動和bboss持久層
<dependency>
  <groupId>org.elasticsearch.plugin</groupId>
  <artifactId>jdbc</artifactId>
  <version>6.3.2</version>
</dependency>
<dependency> 
    <groupId>com.bbossgroups</groupId> 
    <artifactId>bboss-persistent</artifactId> 
    <version>5.3.6</version> 
</dependency> 

在pom中添加elastic maven庫 

<repositories>
  <repository>
    <id>elastic.co</id>
    <url>https://artifacts.elastic.co/maven</url>
  </repository>
</repositories>

2.經過jdbc驅動執行elasticsearch sql相關功能

• 啓動es數據源
• 執行elasticsearch sql相關功能

直接看執行各類sql功能的代碼ESJdbcTest：

package com.frameworkset.sqlexecutor;
/*
 *  Copyright 2008 biaoping.yin
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

import com.frameworkset.common.poolman.SQLExecutor;
import com.frameworkset.common.poolman.util.SQLUtil;
import org.junit.Test;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;

public class ESJdbcTest {

	public void initDBSource(){
		SQLUtil.startPool("es",//ES數據源名稱
				"org.elasticsearch.xpack.sql.jdbc.jdbc.JdbcDriver",//ES jdbc驅動
				"jdbc:es://http://127.0.0.1:9200/timezone=UTC&page.size=250",//es連接串
				"elastic","changeme",//es x-pack帳號和口令
				"SHOW tables 'dbclob%'" //數據源鏈接校驗sql
		);
	}

	/**
	 * 執行一個查詢
	 * @throws SQLException
	 */
	@Test
	public void testSelect() throws SQLException {
		initDBSource();//啓動數據源
		//執行查詢，將結果映射爲HashMap集合
		 List<HashMap> data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SELECT SCORE() as score,content as content FROM dbclobdemo");
		 System.out.println(data);
	}

	/**
	 * 進行模糊搜索，Elasticsearch 的搜索能力你們都知道，強！在 SQL 裏面，能夠用 match 關鍵字來寫，以下：
	 * @throws SQLException
	 */
	@Test
	public void testMatchQuery() throws SQLException {
		initDBSource();
		List<HashMap> data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SELECT SCORE(), * FROM dbclobdemo WHERE match(content, '_ewebeditor_pa_src') ORDER BY documentId DESC");
		System.out.println(data);

		/**
		 *還能試試 SELECT 裏面的一些其餘操做，如過濾，別名，以下：
		 */
		data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SELECT SCORE() as score,title as myname FROM dbclobdemo  as mytable WHERE match(content, '_ewebeditor_pa_src') and (title.keyword = 'adsf' OR title.keyword ='elastic') limit 5 ");
		System.out.println(data);
	}
	/**
	 * 分組和函數計算
	 */
	@Test
	public void testGroupQuery() throws SQLException {
		initDBSource();
		List<HashMap> data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SELECT title.keyword,max(documentId) as max_id FROM dbclobdemo as mytable group by title.keyword limit 5");
		System.out.println(data);


	}


	/**
	 * 查看全部的索引表
	 * @throws SQLException
	 */
	@Test
	public void testShowTable() throws SQLException {
		initDBSource();
		List<HashMap> data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW tables");
		System.out.println(data);
	}

	/**
	 * 如 dbclob 開頭的索引，注意通配符只支持 %和 _，分別表示多個和單個字符（什麼，不記得了，回去翻數據庫的書去！）
	 * @throws SQLException
	 */
	@Test
	public void testShowTablePattern() throws SQLException {
		initDBSource();
		List<HashMap> data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW tables 'dbclob_'");
		System.out.println(data);
		data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW tables 'dbclob%'");
		System.out.println(data);
	}
	/**
	 * 查看索引的字段和元數據
	 * @throws SQLException
	 */
	@Test
	public void testDescTable() throws SQLException {
		initDBSource();
		List<HashMap> data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","DESC dbclobdemo");
		System.out.println(data);
		data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW COLUMNS IN dbclobdemo");
		System.out.println(data);
	}

	/**
	 * 不記得 ES 支持哪些函數，只須要執行下面的命令，便可獲得完整列表
	 * @throws SQLException
	 */
	@Test
	public void testShowFunctin() throws SQLException {
		initDBSource();
		List<HashMap> data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW FUNCTIONS");
		System.out.println(data);
		//一樣支持通配符進行過濾：
		data =	SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW FUNCTIONS 'S__'");
		System.out.println(data);

	}
}

若是執行的時候報錯：

能夠採用正式的license或者在elasticsearch.yml文件最後添加如下配置便可：

xpack.license.self_generated.type: trial

3.bboss 針對es jdbc的替代解決方案

 

bboss 提供一組sql和fetchQuery API，可替代es jdbc模塊；採用bboss便可擁有bboss的客戶端自動發現和容災能力、對es、jdk、spring boot的兼容性能力，又能夠擁有es jdbc的全部功能，同時還解決了由於引入es jdbc致使項目對es版本的強依賴和兼容性問題，參考demo：

orm查詢
https://gitee.com/bbossgroups/eshelloword-booter/blob/master/src/test/java/org/bboss/elasticsearchtest/sql/SQLOrmTest.java
分頁查詢
https://gitee.com/bbossgroups/eshelloword-booter/blob/master/src/test/java/org/bboss/elasticsearchtest/sql/SQLPagineTest.java

開發交流

elasticsearch sql官方文檔：

https://www.elastic.co/guide/en/elasticsearch/reference/current/xpack-sql.html

elasticsearch技術交流：166471282

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