Simple Java program to perform CRUD operations in Elastic Search using RestHighLevelClient. (Elastic search basic operations)

ESBasicOperations.java

package es;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.apache.http.HttpHost;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexRequest;
import org.elasticsearch.action.admin.indices.delete.DeleteIndexResponse;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.delete.DeleteResponse;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
import org.elasticsearch.client.RestClient;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.builder.SearchSourceBuilder;

public class ESBasicOperations {

	private static List<Map<String, Object>> resultSetToList(ResultSet rs) throws SQLException {
	    ResultSetMetaData md = rs.getMetaData();
	    int columns = md.getColumnCount();
	    List<Map<String, Object>> rows = new ArrayList<Map<String, Object>>();
	    while (rs.next()){
	        Map<String, Object> row = new LinkedHashMap<String, Object>(columns);
	        for(int i = 1; i <= columns; ++i){
	            row.put(md.getColumnName(i), rs.getObject(i));
	        }
	        rows.add(row);
	    }
	    return rows;
	}

	public static void main(String[] args) throws ParseException {
		RestHighLevelClient client = new RestHighLevelClient(
		        RestClient.builder(
		                new HttpHost("localhost", 9200, "http")));
		Connection connection = null;
		Statement statement = null;
		try {
			Class.forName("com.mysql.jdbc.Driver");
			connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/company", "root", "root");
			statement = connection.createStatement();
			ResultSet rs = statement.executeQuery("SELECT * FROM employees");
			List<Map<String, Object>> listOfMap = resultSetToList(rs);
			System.out.println("----------Deleting Index: company------");
			deleteIndex(client);
			System.out.println("----------Creating Index: company (With bulk data from DB)------");
			bulkCreate(client, listOfMap);
			System.out.println("----------After Bulk Insert------");
			viewIndex(client);
			System.out.println("----------Adding one record to type 'employees' under index 'company'------");
			createIndex(client);
			System.out.println("----------After Inserting one record------");
			viewIndex(client);
			System.out.println("----------Updating Record Abubakkar Siddique age from 24 to 25------");
			updateIndex(client);
			System.out.println("----------After Updating------");
			viewIndex(client);
			System.out.println("----------Deleting user Abubakkar Siddique------");
			deleteEntry(client);
			System.out.println("----------After Deleting------");
			viewIndex(client);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				client.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	private static void createIndex(RestHighLevelClient client) {
		String json = "{" +
		        "\"name\":\"shaik ghouse\"" +
		        ",\"age\":\"23\"" +
		    "}";
		try {
			IndexRequest req = new IndexRequest("company", "employees", "4"/*optional*/);
			req.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
			req.source(json, XContentType.JSON);
			client.index(req);
		} catch (IOException e1) {
			e1.printStackTrace();
		}
	}

	private static void viewIndex(RestHighLevelClient client) {
		SearchRequest searchRequest = new SearchRequest("company/employees"); 
		SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
		searchSourceBuilder.size(1000);
		searchSourceBuilder.sort("_id");
		searchSourceBuilder.query(QueryBuilders.matchAllQuery());
		searchRequest.source(searchSourceBuilder);
		try {
			SearchResponse searchResponse = client.search(searchRequest);
			SearchHit[] values = searchResponse.getHits().getHits();
			if(values.length > 0) {
				for(SearchHit s : values) {
					System.out.println(s.getSourceAsString());
				}	
			} else {
				System.out.println("No results found!");
			}
		} catch (IOException e) {
			e.printStackTrace();
		}

	}

	private static void updateIndex(RestHighLevelClient client) {
		String json = "{" +
			        "\"name\":\"Abubakkar Siddique\"" +
			        ",\"age\":\"25\"" +
			    "}";
		try {
			IndexRequest req = new IndexRequest("company", "employees", "1"/*optional*/);
			req.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
			req.source(json, XContentType.JSON);
			client.index(req);
		} catch (IOException e1) {
			e1.printStackTrace();
		}
	}

	private static void bulkCreate(RestHighLevelClient client, List<Map<String, Object>> list) {
		try {
			BulkRequest request = new BulkRequest();
			request.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
			int index = 0;
			for(Map<String, Object> map : list) {
				request.add(new IndexRequest("company", "employees", String.valueOf(++index))  
				        .source(map, XContentType.JSON));
			}
			client.bulk(request);
		} catch (Exception e) {
			e.printStackTrace();
		}

	}

	private static void deleteEntry(RestHighLevelClient client) throws IOException {
		DeleteRequest deleteRequest = new DeleteRequest("company", "employees", "1");
		deleteRequest.setRefreshPolicy(RefreshPolicy.IMMEDIATE);
		DeleteResponse res = client.delete(deleteRequest);
		System.out.println("Deleted: " + res.status());
	}

	private static void deleteIndex(RestHighLevelClient client) throws IOException {
		DeleteIndexRequest deleteRequest = new DeleteIndexRequest("company");	
		DeleteIndexResponse res = client.indices().delete(deleteRequest);
		System.out.println("Deleted:" + res.isAcknowledged());
	}
}