In this tutorial, we will learn how to use Spring Boot with Spring data JPA and Elastic Search to index data using elastic search and search data from the indexes.

Key Benefits from this :

• We will make a REST API endpoint to index data into Elastic Search.
• We will also make a REST API endpoint to search data using Elastic Search from the indexed data.
• We will make a REST API to reindex the data.
• We will make a REST API to delete all indexes of Elastic Search.

Final Project Structure will look like this

1. Add Maven Dependency Or use Spring Initializr

Add the 4 dependencies 

• spring data jpa
• h2 in-memory database
• Elastic search 
• Spring web – for tomcat and spring REST 

and generate the project if using spring initializr Or you can also add them directly to spring boot pom.xml.

So the Pom file will look like this.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
     <version>1.5.9.RELEASE</version>
     <relativePath/> <!-- lookup parent from repository -->
  </parent>
  <groupId>com.test</groupId>
  <artifactId>sprinbootelastic</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>sprinbootelastic</name>
  <description>Demo project for Spring Boot</description>

  <properties>
     <java.version>1.8</java.version>
  </properties>

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

     <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <scope>runtime</scope>
     </dependency>
     <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
           <exclusion>
              <groupId>org.junit.vintage</groupId>
              <artifactId>junit-vintage-engine</artifactId>
           </exclusion>
        </exclusions>
     </dependency>
     <dependency>
        <groupId>org.elasticsearch.client</groupId>
        <artifactId>transport</artifactId>
        <version>6.8.6</version>
     </dependency>
  </dependencies>

  <build>
     <plugins>
        <plugin>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
     </plugins>
  </build>

</project>

2. Create : Spring Data Entity

Create an entity called Employee.class – and annotate it also with @Document with index name and its type.

package com.test.sprinbootelastic.entities;

import javax.persistence.*;
import java.io.Serializable;

@Entity
@Table(name = "Employee")
@Document(indexName = "employee", type = "employee",shards = 1)
public class Employee implements Serializable {

   private static final long serialVersionUID = -1798070786993154676L;

   @Id
   private Integer id;

   @Column(name="name")
   private String name;

   @Column(name="address")
   private String address;

   public int getId() {
       return id;
   }

   public void setId(int id) {
       this.id = id;
   }

   public String getName() {
       return name;
   }

   public void setName(String name) {
       this.name = name;
   }

   public String getAddress() {
       return address;
   }

   public void setAddress(String address) {
       this.address = address;
   }

}

3. Spring Data Repository + Elastic Search Repository

Create a Spring Data Repository Interface like below and go to the next step.

Here we created a Repository which Spring Data JPA has provided and extend a CrudRepository which provides us some boilerplate code and functionalities which helps us interact with the database just like a normal JPA or Hibernate would do.

package com.test.sprinbootelastic.repository;

import com.test.sprinbootelastic.entities.Employee;
import org.springframework.data.repository.CrudRepository;

public interface EmployeeRepository  extends CrudRepository<Employee,Integer> {

   Employee findById(int id);

}

Also create an Elastic Search Repository

package com.test.sprinbootelastic.elasticrepo;

import com.test.sprinbootelastic.entities.Employee;
import org.springframework.data.elasticsearch.repository.ElasticsearchRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface EmpRepository extends ElasticsearchRepository<Employee,Integer> {
}

4. Connection with H2 in-memory database

Just add the below 2 properties for h2 db in application.properties

spring.h2.console.enabled=true
spring.h2.console.path=/h2

Also, Just For Testing Create two sample .sql scripts to create an Employee table and insert 2 records into that table on application load or startup.

Create 2 scripts as shown in the snapshot below:

Script.sql

Drop table if exists Employee;

Create table (id number , string name, string address);

Data.sql

insert into Employee (id,name,address) values (1,'John','US');
insert into Employee (id,name,address) values (2,'Mak','UK');

5. Config – Elastic Search

Create a Config Class file for elastic search configuration

package com.test.sprinbootelastic;

import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.node.NodeBuilder;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
import org.springframework.data.elasticsearch.core.ElasticsearchTemplate;
import org.springframework.data.elasticsearch.repository.config.EnableElasticsearchRepositories;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

import java.io.File;
import java.io.IOException;

@Configuration
@EnableElasticsearchRepositories(basePackages = "com.test.sprinbootelastic.elasticrepo")
@EnableJpaRepositories(basePackages = "com.test.sprinbootelastic.repository")
@ComponentScan(basePackages = {"com.test.sprinbootelastic"})
public class Config {

   @Value("${elasticsearch.home:C:/Users/programmertoday/test}")
   private String elasticsearchHome;

   @Value("${elasticsearch.cluster.name:elastic-1}")
   private String clusterName;

   @Bean
   public NodeBuilder nodeBuilder() {
       return new NodeBuilder();
   }

   @Bean
   public ElasticsearchOperations elasticsearchTemplate() throws IOException {
       File tmpDir = File.createTempFile("elastic1", Long.toString(System.nanoTime()));
       System.out.println("Temp directory: " + tmpDir.getAbsolutePath());
       Settings.Builder elasticsearchSettings =
               Settings.settingsBuilder()
                       .put("http.enabled", "true") // 1
                       .put("index.number_of_shards", "1")
                       .put("path.data", new File(tmpDir, "data").getAbsolutePath()) // 2
                       .put("path.logs", new File(tmpDir, "logs").getAbsolutePath()) // 2
                       .put("path.work", new File(tmpDir, "work").getAbsolutePath()) // 2
                       .put("path.home", tmpDir); // 3


       return new ElasticsearchTemplate(nodeBuilder()
               .local(true)
               .settings(elasticsearchSettings.build())
               .node()
               .client());
   }
}

6. Class ElasticSearchIndexer.class

Create a class called ElasticSearchIndexer which helps in indexing Employee entity data which was stored in the h2 or any DB.

This class will be called from the controller.

package com.test.sprinbootelastic.util;

import com.test.sprinbootelastic.elasticrepo.EmpRepository;
import com.test.sprinbootelastic.entities.Employee;
import com.test.sprinbootelastic.repository.EmployeeRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.elasticsearch.core.ElasticsearchOperations;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

@Service
public class ElasticSearchIndexer {

   @Autowired
   ElasticsearchOperations operations;

   @Autowired
   EmpRepository empRepository;

   @Autowired
   EmployeeRepository employeeRepository;

   public void indexData(){
       System.out.println("start data indexing**********");
       operations.putMapping(Employee.class);
       System.out.println("Loading Data Employee");
       empRepository.save(getData());
       System.out.printf("Loading Completed");
   }

   private Iterable<Employee> getData() {
       List<Employee> list = new ArrayList<Employee>();
       Iterable<Employee> emps = employeeRepository.findAll();
       emps.forEach(list::add);
       return emps;
   }

}

7. Controller – Elastic Search REST End Points

REST API endpoints for elastic search.

package com.test.sprinbootelastic.controllers;

import com.test.sprinbootelastic.elasticrepo.EmpRepository;
import com.test.sprinbootelastic.entities.Employee;
import com.test.sprinbootelastic.repository.EmployeeRepository;
import com.test.sprinbootelastic.util.ElasticSearchIndexer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.ArrayList;
import java.util.List;

@RestController
@RequestMapping("api")
public class EmployeeController {

   @Autowired
   public EmployeeRepository employeeRepository;
   @Autowired
   public EmpRepository empRepository;
   @Autowired
   public ElasticSearchIndexer elasticSearchIndexer;

   @GetMapping("/employee")
   public Employee getEmployee() {
       System.out.println("** This is spring boot application **");
       Employee emp = new Employee();
       emp = employeeRepository.findById(1);
       System.out.println("employe :" + emp);
       return emp;
   }

   /***** Elastic Search APIs *****/

   @GetMapping(value = "/es/index")
   public String indexEmployee() {
       elasticSearchIndexer.indexData();
       return "Data indexed Successfully";
   }

   @GetMapping(value = "/all")
   public List<Employee> searchAll() {
       List<Employee> usersList = new ArrayList<>();
       Iterable<Employee> emps = empRepository.findAll();
       emps.forEach(usersList::add);
       return emps;
   }

   @GetMapping(value = "/es/deleteindexes")
   public String deleteIndexes() {
       empRepository.deleteAll();
       return "Deleted all indexes";
   }


}

8. Run Main method – @SpringBootApplication

Now just open the main class and run it.

Voila ! 

Your SpringBoot Spring Data JPA with Elastic Search application is up and running @ localhost:port

Default port will be 8080 [ example : localhost:8080 ]

You can hit the following Elastic Search REST end points like below:

localhost:8080/api/es/index : to create the indexed of the data present in db
localhost:8080/api/all : to search entire Employee indexed data
localhost:8080/api/deleteindexes : to delete all the indexes

Summary

In this tutorial, we learnt about Spring boot capabilities with Spring DATA Elastic Search which allows simple integration with elastic search, we created a few REST endpoints of elastic search to index and search the data.
Hope you liked it !

---