Here we will see how to insert documents to Elasticsearch cluster.

Versions:

• Elasticsearch
• Java8
• Maven

Dependencies:

Add the below dependencies to your pom.xml to work with elasticsearch.

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>5.6.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.elasticsearch.client/transport -->
<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>transport</artifactId>
    <version>5.6.0</version>
</dependency>

1. Insert documents to elasticsearch:

Adding JSON documents to an elasticsearch cluster.

1.1 Creating Elasticearch transport client:

I have installed elasticsearch on my windows machine, and HTTP port is running on 9200, transport port is running on 9300.  The below code snippet is to create elasticsearch transport client, it connects with local elasticsearch cluster.

public static Client getClient() throws UnknownHostException {
        Client client = new PreBuiltTransportClient(
                Settings.builder().put("client.transport.sniff", true)
                        .put("cluster.name","elasticsearch").build())
                .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));
        return client;
}

1.2 Insert JSON messages to Elasticseach cluster:

prepareIndex() method is used to store JSON message to an elasticsearch cluster and make it as searchable. It has three parameters which are indexName, type and documentId. In the following example; the indexName is otp, type is items and documentId is 1.

public static void insertJson() throws UnknownHostException {
        String jsonObject = "{\"name\":\"Lenovo\","
                +"\"category\":\"Laptop\","
                +"\"description\":\"Lenovo Laptops\"}";
        IndexResponse response = getClient().prepareIndex("otp", "items","1")
                .setSource(jsonObject, XContentType.JSON).get();
    }

On the above example, we manually created the JSON string. Instead, you can use any of JSON libraries available in the market.

Output:

If you are not familiar with any of the JSON libraries, you can use elasticsearch helper – XContentFactory to build JSON documents like the following.

1.3 Building JSON documents with XContentFactory:

XContentBuilder builder = XContentFactory.jsonBuilder()
                .startObject()
                .field("name", "Spring in Action")
                .field("category", "Books")
                .field("description", "Spring Books")
                .endObject();
        IndexResponse response = getClient().prepareIndex("otp", "items","4")
                .setSource(builder).get();

Output:

1.4 Insert Java Map to Elasticsearch cluster:

We can also insert the data into Elsticsearch cluster as Java Map like below.

public static void insertMap() throws UnknownHostException {
        Map<String,Object> data = new HashMap<>();
        data.put("name","iPhoneX");
        data.put("category","Mobiles");
        data.put("description","Apple Mobiles");
        IndexResponse response = getClient().prepareIndex("otp", "items","3")
                .setSource(data).get();
    }

Output:

2. Elasticsearch insert complete Example:

package com.onlinetutorialspoint;

import org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.client.Client;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.transport.client.PreBuiltTransportClient;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Map;

public class ElasticseachInsert {
    public static void main(String[] args) throws IOException {
        insertAsJsonBuilder();
    }

    public static void insertMap() throws UnknownHostException {
        Map<String,Object> data = new HashMap<>();
        data.put("name","iPhoneX");
        data.put("category","Mobiles");
        data.put("description","Apple Mobiles");
        IndexResponse response = getClient().prepareIndex("otp", "items","3")
                .setSource(data).get();
    }

    public static void insertJson() throws UnknownHostException {
        String jsonObject = "{\"name\":\"Lenovo\","
                +"\"category\":\"Laptop\","
                +"\"description\":\"Lenovo Laptops\"}";
        IndexResponse response = getClient().prepareIndex("otp", "items","1")
                .setSource(jsonObject, XContentType.JSON).get();
    }
    public static void insertAsJsonBuilder() throws IOException {
        XContentBuilder builder = XContentFactory.jsonBuilder()
                .startObject()
                .field("name", "Spring in Action")
                .field("category", "Books")
                .field("description", "Spring Books")
                .endObject();
        IndexResponse response = getClient().prepareIndex("otp", "items","4")
                .setSource(builder).get();
    }

    public static Client getClient() throws UnknownHostException {
        Client client = new PreBuiltTransportClient(
                Settings.builder().put("client.transport.sniff", true)
                        .put("cluster.name","elasticsearch").build())
                .addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName("localhost"), 9300));
        return client;
    }
}

References:

• Elasticsearch insert docs
• How to install Elasticsearch on windows 10

Happy Learning 🙂