Elasticsearch 6.3以后的版本可以通过jdbc操作es，该功能还在不断的完善当中，本文介绍es jdbc使用方法。
1.首先在工程中导入es jdbc maven坐标：
导入elasticsearch jdbc驱动和bboss持久层
<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>5.0.7.7</version>
</dependency>
在pom中添加elastic maven库
<repositories>
<repository>
<id>elastic.co</id>
<url>https://artifacts.elastic.co/maven</url>
</repository>
</repositories>
2.通过jdbc驱动执行elasticsearch sql相关功能
启动es数据源
执行elasticsearch sql相关功能
直接看执行各种sql功能的代码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数据源名称
"org.elasticsearch.xpack.sql.jdbc.jdbc.JdbcDriver",//ES jdbc驱动
"jdbc:es://http://127.0.0.1:9200/timezone=UTC&page.size=250",//es链接串
"elastic","changeme",//es x-pack账号和口令
"SHOW tables 'dbclob%'" //数据源连接校验sql
);
}
/**
* 执行一个查询
* @throws SQLException
*/
@Test
public void testSelect() throws SQLException {
initDBSource();//启动数据源
//执行查询，将结果映射为HashMap集合
List<HashMap> data = SQLExecutor.queryListWithDBName(HashMap.class,"es","SELECT SCORE() as score,content as content FROM dbclobdemo");
System.out.println(data);
}
/**
* 进行模糊搜索，Elasticsearch 的搜索能力大家都知道，强！在 SQL 里面，可以用 match 关键字来写，如下：
* @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);
/**
*还能试试 SELECT 里面的一些其他操作，如过滤，别名，如下：
*/
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);
}
/**
* 分组和函数计算
*/
@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);
}
/**
* 查看所有的索引表
* @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 开头的索引，注意通配符只支持 %和 _，分别表示多个和单个字符（什么，不记得了，回去翻数据库的书去！）
* @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数据
* @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);
}
/**
* 不记得 ES 支持哪些函数，只需要执行下面的命令，即可得到完整列表
* @throws SQLException
*/
@Test
public void testShowFunctin() throws SQLException {
initDBSource();
List<HashMap> data = SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW FUNCTIONS");
System.out.println(data);
//同样支持通配符进行过滤：
data = SQLExecutor.queryListWithDBName(HashMap.class,"es","SHOW FUNCTIONS 'S__'");
System.out.println(data);
}
}
如果执行的时候报错：
可以采用正式的license或者在elasticsearch.yml文件最后添加以下配置即可：
xpack.license.self_generated.type: trial
3.bboss 针对es jdbc的替代解决方案
bboss 提供一组sql和fetchQuery API，可替代es jdbc模块；采用bboss即可拥有bboss的客户端自动发现和容灾能力、对es、jdk、spring boot的兼容性能力，又可以拥有es jdbc的所有功能，同时还解决了因为引入es jdbc导致项目对es版本的强依赖和兼容性问题，参考demo：
orm查询
https://gitee.com/bbossgroups/eshelloword-booter/blob/master/src/test/java/org/bboss/elasticsearchtest/sql/SQLOrmTest.java
分页查询
https://gitee.com/bbossgroups/eshelloword-booter/blob/master/src/test/java/org/bboss/elasticsearchtest/sql/SQLPagineTest.java
开发交流
elasticsearch sql官方文档：
https://www.elastic.co/guide/en/elasticsearch/reference/current/xpack-sql.html
elasticsearch技术交流群：166471282
elasticsearch微信公众号：
