Skip to main content

Custom implementation for a Spring Data Solr Repository

In this article we are going to write the our own implementation for Solr repository and add some custom methods to it, However I am going to cover every little details but you should have little bit idea of Apache Solr, Spring Boot Repositories to understand this article.

Apache Solr is basically an open source web application built on top of Apache lucene search API but Solr provides lots of extra functionalities than lucene. You don't need to be a Java programmer to perform search on Solr it provides a cool user interface with help of its REST-like APIs, We can do approx everything on this UI without having any knowledge of programming with little bit configuration. Rather than this Solr also provides advanced and optimised full text search, integration with Apache UIMA and Apache Tika and lots more you can see them official website of solr.

With initiations convention over configuration Spring introduced a new framework named Spring Boot, Spring Boot has a lots of advance thing and one of them is the concept of repositories. Spring boot Repositories have some methods which are commonly used while writing any enterprise apps.

Here we are going to use Spring boot Solr repository and provide some custom implementation for that repository.

First of all we need to setup a rough maven project structure, we can generate and download it from Spring Initializer or we can create it.

Now let's move our demo application, here I am going to create complete project from scratch in below simple steps.

Step 1. Create A maven project with Java 8 archtype






Step 2. Download, install and configure Apache Solr Http server, and create a core. I have created a core by name basic_core by using basic_configs.

Step 3. Add spring-boot-starter and spring-data-solr dependencies to your pom.xml file.

Step 4. Create below configuration classes and add solr.server.url=http://localhost:8983/solr/basic_core to application.properties file under resources folder.

CustomSolrRepoApp.java
Marking our class with @SpringBootApplication is same as marking the class with @Documented, @Inherited, @Configuration, @EnableAutoConfiguration, @ComponentScan  annotations

It is not general practice to write any code in this class rather than 

SpringApplication.run(CustomSolrRepoApp.class, args); 

But in this class I am getting the repository bean from application context and then creating dummy data with help of that repository instance and then calling findall() method of SolrRepository class and also our custom getLastNames() method which will give us unique list of lastnames present in our dummy data.

SolrConfig.java
Here we are creating beans for SolrServer and SolrTemplate, Here we are using HttpSolrServer to communicate with Apache solr, however we can also use EmbeddedSolrServerFactoryBean for same purpose. EmbeddedSolrServerFactoryBean is only good for dev server not production server.


Step 5. Create Employee model class

Employee.java
Mark id field with @Id and @Field annotation and other fields with @Field annotation

Step 6. Create repositories, custom repository and repository implementations

CustomSolrRepository.java
Define all your custom methods in this interface

EmployeeRepository.java
This class extends CustomSolrRepository and SolrCrudRepository interface here, This interface will be treated as Solr repository reference

EmployeeRepositoryImpl.java
This should be named as EmployeeRepository + impl according spring boot repository name convention. This class should also marked as @Repository annotation and it should also provide implementations for CustomSolrRepository's methods

To see the output we need to run CustomSolrRepoApp as java application as we can see in below screenshot first we will have the complete list of employees and then we will have list of unique last names.


At the end I want to say thanks for reading, Please feel free to contact me if you found anything wrong or phase any other problem, or if you just want to talk.
Labels:

Comments

Post a Comment

Popular posts from this blog

Why Single Java Source File Can Not Have More Than One public class

According to Java standards and common practices we should declare every class in its own source file. And even if we declare multiple classes in the single source file (.java) still each class will have its own class file after compilation. But the fact is that we can declare more than one class in a single source file with below constraints, Each source file should contain only one public class and the name of that public class should be similar to the name of the source file. If you are declaring the main method in your source file then main should lie in that public class If there is no public class in the source file then main method can lie in any class and we can give any name to the source file. If you are not following 1st constraint then you will receive a compilation error saying “ The public type A must be defined in its own file ”.  While if you are not following the second constraint you will receive an error “ Error: Could not find or load main class User ” after exec
3 comments
Read more

AutoWiring Spring Beans Into Classes Not Managed By Spring Like JPA Entity Listeners

In my previous article JPA Auditing: Persisting Audit Logs Automatically using EntityListeners , I have discussed how we can use Spring Data JPA automate Auditing and automatically create audit logs or history records and update CreatedBy, CreatedDate, LastModifiedBy, LastModifiedDate properties. So in order to save history records for our File entity, we were trying to auto-wire EntityManager inside our FileEntityListener class and we have come to know that we can not do this. We can not inject any Spring-managed bean in the EntityListener because EntityListeners are instantiated by JPA before Spring inject anything into it. EntityListeners are not managed Spring so Spring cannot inject any Spring-managed bean e.g. EntityManager in the EntityListeners. And this case is not just with EntityListeners, you can not auto wire any Spring-managed bean into another class (i.e. utility classes) which is not managed by Spring. Because it is a very common problem and can also arise with other c
7 comments
Read more

How Does JVM Handle Method Overloading and Overriding Internally

In my previous article Everything About Method Overloading Vs Method Overriding , I have discussed method overloading and overriding, their rules and differences. In this article, we will see How Does JVM Handle Method Overloading And Overriding Internally, how JVM identifies which method should get called. Let’s take the example of parent class  Mammal and a child  Human classes from our previous blog to understand it more clearly. public class OverridingInternalExample { private static class Mammal { public void speak() { System.out.println("ohlllalalalalalaoaoaoa"); } } private static class Human extends Mammal { @Override public void speak() { System.out.println("Hello"); } // Valid overload of speak public void speak(String language) { if (language.equals("Hindi")) System.out.println("Namaste"); else System.out.println("Hello"); } @
8 comments
Read more