请使用springboot写一个api返回查询ES数据源的索引，接口参数为ES数据源id和表名

以下是一个简单的实现：

1. 首先需要在pom.xml文件中添加elasticsearch的依赖：

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-data-elasticsearch</artifactId>
</dependency>

2. 在application.properties中配置elasticsearch的连接信息：

spring.data.elasticsearch.cluster-nodes=localhost:9300
spring.data.elasticsearch.cluster-name=my-application

3. 创建一个Elasticsearch的Repository类：

import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;

public interface ElasticsearchIndexRepository extends ElasticsearchRepository<Index, String> {
    Index findByDataSourceIdAndTableName(String dataSourceId, String tableName);
}

4. 创建一个Controller类：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ElasticsearchIndexController {

    @Autowired
    private ElasticsearchIndexRepository elasticsearchIndexRepository;

    @GetMapping("/indices/{dataSourceId}/{tableName}")
    public Index getIndex(@PathVariable String dataSourceId, @PathVariable String tableName) {
        return elasticsearchIndexRepository.findByDataSourceIdAndTableName(dataSourceId, tableName);
    }

}

5. Index类需要实现序列化接口，并且需要定义@Document注解：

import org.springframework.data.annotation.Id;
import org.springframework.data.elasticsearch.annotations.Document;

import java.io.Serializable;

@Document(indexName = "indices", type = "index")
public class Index implements Serializable {

    @Id
    private String id;

    private String dataSourceId;

    private String tableName;

    // getters and setters

}

6. 运行项目，访问`http://localhost:8080/indices/{dataSourceId}/{tableName}`即可查询对应的索引信息。