Spring Boot 2 Spring Data Kotlin Cassandra CRUD

we're integration Spring Boot Kotlin Cassandra  CRUD.

• Configuration Spring boot, Spring Data, Kotlin with Cassandra Database.
• Define Data's Models, Repository and Services.
• Spring Rest Controllers  

Spring Boot Kotlin Cassandra Rest CRUD API 

These are APIs that we need to provide:

Methods	Urls
POST	/services/ws/save
GET	/services/ws/users
PUT	/services/ws/update/:email
DELETE	/services/ws/delete/:email

Technology

• Kotlin 1.5.31
• Java 11
• Spring Boot 2.5.6
• Cassandra 4.0.1
• Cqlsh 6.0.0
• Maven 3.6.3
• IntelliJ IDEA 2021.2.3 
• Docker

Project Structure

Configuration Spring Boot kotlin Cassandra project 

•  Spring Initializr or Spring Suite Tool (STS).
• Maven

pom.xml

<?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>2.5.6</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.henry</groupId>
   <artifactId>SpringBootCassandraKotlin</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>SpringBootCassandraKotlin</name>
   <description>Crud Cassandra with kotlin</description>
   <properties>
      <java.version>11</java.version>
      <kotlin.version>1.5.31</kotlin.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-data-cassandra</artifactId>
      </dependency>
      <dependency>
         <groupId>org.jetbrains.kotlin</groupId>
         <artifactId>kotlin-reflect</artifactId>
      </dependency>
      <dependency>
         <groupId>org.jetbrains.kotlin</groupId>
         <artifactId>kotlin-stdlib-jdk8</artifactId>
      </dependency>

      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>

   </dependencies>

   <build>
      <sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
      <testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
         <plugin>
            <groupId>org.jetbrains.kotlin</groupId>
            <artifactId>kotlin-maven-plugin</artifactId>
            <configuration>
               <args>
                  <arg>-Xjsr305=strict</arg>
               </args>
               <compilerPlugins>
                  <plugin>spring</plugin>
               </compilerPlugins>
            </configuration>
            <dependencies>
               <dependency>
                  <groupId>org.jetbrains.kotlin</groupId>
                  <artifactId>kotlin-maven-allopen</artifactId>
                  <version>${kotlin.version}</version>
               </dependency>
            </dependencies>
         </plugin>
      </plugins>
   </build>

</project>

application.yml

server:
  servlet:
    context-path: /services
  port: 9000

spring:
  data:
    cassandra:
      keyspace-name: test_keyspace
      contact-points: localhost:9042
      local-datacenter: datacenter1

Set up Cassandra by Docker

docker pull cassandra

 docker run --name cassandra -p 127.0.0.1:9042:9042 -p 127.0.0.1:9160:9160   -d cassandra

 docker exec -it cassandra /bin/bash

 #cqlsh

Check datacenter name:

cqlsh> use system;

cqlsh:system> select data_center from local;

 data_center

-------------

 datacenter1

(1 rows)

cqlsh:system>

 

We Created keyspaces: test_keyspace.

create keyspace test_keyspace with replication={'class':'SimpleStrategy', 'replication_factor':1};

use test_keyspace;

create table users

(

    email varchar primary key,

    name varchar,

    age int

);

Data class model

package com.henry.model

import org.springframework.data.cassandra.core.mapping.PrimaryKey
import org.springframework.data.cassandra.core.mapping.Table

@Table
data class Users(@PrimaryKey
                 var email: String, var name: String, var age: Int)

Repository Interface

package com.henry.repository

import com.henry.model.Users
import org.springframework.data.cassandra.repository.CassandraRepository

interface UserRepository : CassandraRepository<Users,String> {
    fun findByNameContaining(name: String?): List<Users?>?

}

Service Interface

package com.henry.services

import com.henry.model.Users

interface UserService {
    fun byContName(name: String): List<Users?>?
    fun findAllUsers(): MutableList<Users>;
    fun saveUser(user: Users): Users
    fun updateUser(email: String, user: Users): Users
    fun deleteUser(email: String)
}

Service Class

package com.henry.services.impl

import com.henry.model.Users
import com.henry.repository.UserRepository
import com.henry.services.UserService
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.stereotype.Service
import java.util.*

@Service
class UserServiceImpl : UserService {

    @Autowired
    lateinit var userRepository: UserRepository;

    override fun byContName(name: String): List<Users?>? {
        return userRepository.findByNameContaining(name)
    }

    override fun findAllUsers(): MutableList<Users> {
        return userRepository.findAll()
    }

    override fun saveUser(user: Users): Users {
        return userRepository.save(user)
    }

    override fun updateUser(email: String, user: Users): Users {
        val obj: Optional<Users> = userRepository.findById(email)
        obj.get().age = user.age
        obj.get().name = user.name
        return userRepository.save(obj.get())

    }

    override fun deleteUser(email: String) {
      userRepository.deleteById(email)
    }
}

Spring Rest APIs Controller

package com.henry.controller

import com.henry.model.Users
import com.henry.services.UserService
import org.springframework.http.HttpStatus
import org.springframework.http.ResponseEntity
import org.springframework.web.bind.annotation.*


@CrossOrigin(origins = ["http://localhost:9000"])
@RestController
@RequestMapping("/ws")
class UserController(private val userService: UserService) {

    @GetMapping("/users")
    fun getAllUsers(): ResponseEntity<MutableList<Users>>? {
        return ResponseEntity(userService.findAllUsers(), HttpStatus.OK)
    }

    @PostMapping("/save")
    fun save(@RequestBody user: Users):  ResponseEntity<Users>?{
        return ResponseEntity(userService.saveUser(user), HttpStatus.OK)
    }

    @PutMapping("/update/{email:.*}")
    fun update(@PathVariable email: String, @RequestBody user: Users):  ResponseEntity<Users>?{
        return ResponseEntity(userService.updateUser(email, user), HttpStatus.OK)
    }

    @DeleteMapping("/delete/{email:.*}")
    fun delete(@PathVariable email: String): ResponseEntity<Unit> {
        return ResponseEntity(userService.deleteUser(email), HttpStatus.OK)
    }




}

Run & Test

Run Spring Boot application with command: mvn spring-boot:run. by console, IntelliJ etc.

POST.

GET.

PUT.

DELETE.

Source Code

Here on Github.

References.

https://www.bezkoder.com/spring-boot-cassandra-crud/

https://www.youtube.com/channel/UCHRnRlWQuZYDmnuB7SbXIpQ