Building Reactive REST CRUD APIs with Spring Boot, Spring WebFlux, Azure Cosmos DB and Azure Cosmos DB SQL API

Hello everyone, Hope you are doing well. In this tutorial, you will learn how to build reactive REST CRUD APIs with Spring Boot, Spring WebFlux, Azure Cosmos DB, and Azure Cosmos DB SQL API.



A little bit of Background

Azure Cosmos DB

Azure Cosmos DB is a fully managed NoSQL database for modern app development. Single-digit millisecond response times, and automatic and instant scalability, guarantee speed at any scale. 

Azure Cosmos DB SQL API

Azure Cosmos DB SQL API accounts provide support for querying items using the Structured Query Language (SQL) syntax.

Spring Boot

Spring Boot makes it easy to create stand-alone, production-grade Spring-based Applications that you can "just run". 

Spring WebFlux

The original web framework included in the Spring Framework, Spring Web MVC, was purpose-built for the Servlet API and Servlet containers. The reactive-stack web framework, Spring WebFlux, was added later in version 5.0. It is fully non-blocking, supports Reactive Streams back pressure, and runs on such servers as Netty, Undertow, and Servlet 3.1+ containers.


After completing this tutorial what we will build? 

We will build REST APIs  CRUD features: 




Step 1: Sign in to Azure Portal and create a resource group

Sign in to Azure portal https://portal.azure.com/#home and find "Resource groups" like below.



Then, create a resource group like the one below.


Here the resource group name is "Knowledgefactory". Create a resource group by clicking the "Review + create " button.




Step 2: Create an Azure Cosmos DB

Select "Azure Cosmos DB",


You will be taken to a page like the below image, Then click on the "Create Azure Cosmos DB account" button.

Select API Option,
Then click on the "create" button of the "Core (SQL) - Recommended" division.


Create Azure Cosmos DB Account - Core (SQL),
Enter/Select Resource group, Account name, etc... Then click on the "Review + create" button.  

You will be taken to a page like the below image, 

Then click on the "Create" button.

Now, You can see "Deployment is in progress" like the below image.

Once deployment is completed you can see the "Your deployment is complete" page like the below image.

Then go to the "Keys" ,


You will be taken to a page like the below image, 
Copy the "URI" value and "PRIMARY KEY" value for future purpose.



Step 3: Add Container 

Click on the "Add Container" button.

Next enter "Database id", "Container id" etc...

Copy that "Database id" and "Container id" for future purpose.



Step 4: Creating a simple spring boot web application.

First, open the Spring initializr https://start.spring.io/

Then, Provide the Group and Artifact name. We have provided Group name com.knf.dev.demo and Artifact spring-webflux-azure-cosmos-db-sql-api-crud. Here I selected the Maven project - language Java - Spring Boot 2.7.1 and add Spring Reactive Web dependency and Azure Cosmos DB dependency. 



Then, click on the Generate button. When we click on the Generate button, it starts packing the project in a .zip(spring-webflux-azure-cosmos-db-sql-api-crud) file and downloads the project. 
Then, Extract the Zip file.



Step 5: Import the project on your favourite IDE, I am using Eclipse IDE

Import the project File -> Import -> Maven ->Existing Maven Project -> Next -> Browse -> Select the project -> Finish

Final Project Directory:



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>2.7.1</version>
      <relativePath/>
   </parent>
   <groupId>com.knf.dev.demo</groupId>
   <artifactId>
        spring-webflux-azure-cosmos-db-sql-api-crud
    </artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>spring-webflux-azure-cosmos-db-sql-api-crud</name>
   <description>Demo project for Spring Boot</description>
   <properties>
      <java.version>17</java.version>
      <spring-cloud-azure.version>
            4.2.0
        </spring-cloud-azure.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-webflux</artifactId>
      </dependency>
      <dependency>
         <groupId>com.azure.spring</groupId>
         <artifactId>
                spring-cloud-azure-starter-data-cosmos
            </artifactId>
      </dependency>

      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
      <dependency>
         <groupId>io.projectreactor</groupId>
         <artifactId>reactor-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>
   <dependencyManagement>
      <dependencies>
         <dependency>
            <groupId>com.azure.spring</groupId>
            <artifactId>
                    spring-cloud-azure-dependencies
                </artifactId>
            <version>${spring-cloud-azure.version}</version>
            <type>pom</type>
            <scope>import</scope>
         </dependency>
      </dependencies>
   </dependencyManagement>

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

</project>



application.yaml

Configure your Spring Boot application to use your Azure Cosmos DB
spring:
  cloud:
    azure:
      cosmos:
        database: <Database id>
        populate-query-metrics: true
        endpoint: <URI>
        key: <PRIMARY KEY>


Create User Model

package com.knf.dev.demo.entity;

import org.springframework.data.annotation.Id;
import com.azure.spring.data.cosmos.core.mapping.Container;
import com.azure.spring.data.cosmos.core.mapping.GeneratedValue;

@Container(containerName = "User")
public class User {
   @Id
   @GeneratedValue
   private String id;
   private String firstName;
   private String lastName;
   private String email;

   public User() {

   }

   public User(String firstName, 
                String lastName, String email) {

      this.firstName = firstName;
      this.lastName = lastName;
      this.email = email;
   }

   public String getId() {
      return id;
   }

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

   public String getFirstName() {
      return firstName;
   }

   public void setFirstName(String firstName) {
      this.firstName = firstName;
   }

   public String getLastName() {
      return lastName;
   }

   public void setLastName(String lastName) {
      this.lastName = lastName;
   }

   public String getEmail() {
      return email;
   }

   public void setEmail(String email) {
      this.email = email;
   }
}
  • @Id annotation is currently used by Spring to support mapping for other non-relational persistence databases or frameworks that do not have a defined common persistence API like JPA.
  • @Container: Annotation for Cosmos Container
  • @GeneratedValue: Used to specify that an entities id field should generate a value



Create Reactive User Repository

package com.knf.dev.demo.repository;

import com.azure.spring.data.cosmos
    .repository.ReactiveCosmosRepository;
import com.knf.dev.demo.model.User;

public interface UserRepository
    extends ReactiveCosmosRepository<User, String> {

}
The ReactiveCosmosRepository interface provides synchronous and reactive APIs for basic save, delete, and find operations.



Create Reactive Rest Controller

package com.knf.dev.demo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.knf.dev.demo.model.User;
import com.knf.dev.demo.repository.UserRepository;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

@RestController
@RequestMapping("/api/v1/users")
public class UserController {

   @Autowired
   private UserRepository repository;

   @GetMapping
   Flux<User> getAll() {
        
      return repository.findAll();
   }

   @GetMapping("/{id}")
   Mono<User> getUser(@PathVariable("id") String id) {
        
      return repository.findById(id);
   }

   @PostMapping
   Mono<User> addUser(@RequestBody User user) {
        
      return repository.save(user);
   }

   @PutMapping("/{id}")
   private Mono<User> updateUser(@PathVariable("id") 
                     String id, @RequestBody User user) {
        
      return repository.findById(id).flatMap(user1 -> {
         user.setId(id);
         return repository.save(user);
      }).switchIfEmpty(Mono.empty());
   }

   @DeleteMapping("/{id}")
   Mono<Void> deleteById(@PathVariable("id") String id) {
        
      return repository.findById(id)
            .flatMap(p -> repository.deleteById(p.getId()));
   }
}



Spring Boot Main Driver

package com.knf.dev.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Application {

   public static void main(String[] args) {
      SpringApplication.run(Application.class, args);
   }

}



                                        

Step 6: Local Setup and Run the application

Step 1: Download or clone the source code from GitHub to a local machine - Click here


Step 2: mvn clean install


Step 3: Run the Spring Boot application - 

mvn spring-boot:run




Step 7: Test the APIs using postman

1. Add User:



2. Get User By Id:



3. Update User:



4. Get All Users:



5. Delete User:

Popular posts from this blog

Learn Java 8 streams with an example - print odd/even numbers from Array and List

Example 1: Java 8 program to print odd numbers from a List   import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; /*Java 8 Program to find Odd Numbers from a List*/ public class DriverClass { public static void main( String [] args) { List < Integer > numbers = Arrays. asList( 1 , 4 , 8 , 40 , 11 , 22 , 33 , 99 ); List < Integer > oddNumbers = numbers.stream(). filter(o -> o % 2 != 0 ). collect(Collectors.toList()); System.out.println(oddNumbers); } } 1. Initialize List using Arrays.asList() method. Java's built-in Arrays.asList() method converts an array into a list. This method takes an array as an argument and returns a List object. 2.  Java List interface provides stream() method which returns a sequential Stream with list of Integer as its source. 3. The Java stream filter(...
Read more

Java Stream API - How to convert List of objects to another List of objects using Java streams?

Image
In this section, we will show you how to convert a List of objects to another List of objects in Java using the Java streams map(). The ‘map’ method maps each element to its corresponding result. Java Stream API   The Java Stream API provides a functional programming approach over the object oriented capabilities of Java. It is used for processing collections of objects. The Stream in Java can be defined as a sequence of elements from a source List, Set or Array. Most of the stream operations return a Stream. This avails engender a chain of stream operations(stream pipe-lining). The streams withal support the aggregate or terminal operations on the elements. for example, finding the sum or maximum element or finding the average etc...Stream operations can either be executed sequentially or parallel. when performed parallelly, it is called a parallel stream.   Stream map() Method   The Java 8 Stream map() is an intermediate operation. It converts Stream<obj1> to Str...
Read more

Registration and Login with Spring Boot + Spring Security + Thymeleaf

Image
In this section, we will learn how to create user registration and login using Spring boot, Spring security, Thymeleaf, JPA, and H2DB. The GitHub repository link is provided at the end of this tutorial. You can download the source code. Technologies used: Spring Boot 2.5.5  Spring Data JPA  Spring Security  Thymeleaf  Maven 3+  Java 17  H2 Database   User Interface User Registration Authentication Failed Authentication success Sign out Final Project Structure: Complete 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-pare...
Read more

Java, Spring Boot Mini Project - Library Management System - Download

Image
Hello everyone, Hope you are doing well. Here, we provide a Library Management System mini-project for beginners, it's free for download. Maybe you can build more on top of this project and create your own product, that's all about you. The source code download link is provided at the end of this post. 1. Benefit of this project You could cover the following technologies and features by learning and debugging this mini project. Java 17 Java Stream Java Lamda Expressions Java Records Functional programming Object-oriented programming var Keyword in Java Generics in Java Java Switch Spring boot 2.6.4 Spring Security Thymeleaf template engine OpenCSV Spring Data JPA Server Side Pagination H2 Database  Bootstrap HTML CSS and more... 2. Objective Of Spring Boot On Library Management System The main objective of this project is to manage the details of the books, author, category, and publisher. Only Admin/Librarian will manage all these activities. Also, they can export the data in ...
Read more

ReactJS, Spring Boot JWT Authentication Example

Image
In this tutorial, we’ll create a user registration & login example using ReactJS, Spring Boot, Spring Security, and JWT authentication. You could download the source code from our Github repository, the download link is provided at the end of this tutorial. Technologies used Backend Technologies: Java 17 Spring Boot 2.7.0 Spring Security Spring Data JPA JWT H2 Database Frontend Technologies: React 17.0.1 Axios 0.27.2 Redux 4.0.5 Bootstrap 4.5.2 ReactJS - SpringBoot - JWT - Flow Backend Project Directory: Frontend Project Directory: Following is the screenshot of our application - User Registration: User Signin: Profile View: Access Resource: We will build two projects:  1. Backend:   spring-boot-security-jwt 2. Frontend: react-redux-jwt Project 1: spring-boot-security-jwt 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"...
Read more

Top 5 Java ORM tools - 2024

Image
  The term ORM refers to object-relational mapping, which uses objects to adapt programming languages to database systems while allowing them to function with SQL and object-oriented programming ideas. Any kind of database management system that can accomplish object mapping to the table in the virtual system is suitable for the implementation of ORM. Java has a wide variety of ORM tools, some of which are mentioned below: 1. Hibernate Hibernate is a lightweight, open-source, non-invasive Java ORM (Object-Relational Mapping) framework that allows developers to create objects that function independently of database software and create persistence logic in any Java or JavaEE application. It offers an abstraction layer, so developers don't have to bother about implementations; Hibernate handles these tasks internally, such as connecting to databases and creating queries to carry out CRUD operations, among other things. Persistence logic development is done with it. Persistence logic r...
Read more

Java - Blowfish Encryption and decryption Example

Image
Blowfish is an encryption method developed by Bruce Schneier in 1993 as an alternative to the DES encryption method. It is significantly faster than DES and provides good encryption speed, although no effective cryptanalysis technique has been found to date. It is one of the first secure block ciphers that is not protected by any patents and is therefore freely available for anyone to use. This is a symmetric block cipher algorithm. Block size: 64 bits Key size: variable size from 32 to 448 bits number of subsections: 18 [P-array] number of rounds: 16 number of substitution blocks: 4 [each with 512 records of 32 bits each] develop  Example 1: Encryption and decryption using Blowfish import java.io.UnsupportedEncodingException; import java.nio.charset.Charset; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.util.Base64; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSiz...
Read more

Spring boot video streaming example-HTML5

Image
Hello everyone, Today we will learn how to stream MP4 video using Spring Boot and Spring Web Flux.  The Source code download link is provided at the end of this post. New, Quarkus Practice User Interface   Project Structure: G radle(build.gradle) plugins { id 'org.springframework.boot' version '2.5.4' id 'io.spring.dependency-management' version '1.0.11.RELEASE' id 'java' } group = 'com.knf.demo' version = '0.0.1-SNAPSHOT' sourceCompatibility = '11' repositories { mavenCentral() } dependencies { implementation 'org.springframework.boot:spring-boot-starter-webflux' testImplementation 'org.springframework.boot:spring-boot-starter-test' testImplementation 'io.projectreactor:reactor-test' } test { useJUnitPlatform() } Service (VideoStreamingService.java) package  com.knf.demo.service ; import org.springframework.beans.factory.annotation. Autowired ; import org.springframework...
Read more

Google Cloud Storage + Spring Boot - File Upload, Download, and Delete

Image
In this section, we will learn  how to  create a simple spring boot application to perform different file operations such as upload, download, list, and delete files from the Google Cloud Storage. 1.  A little bit of Background Google Cloud Storage Cloud Storage is a managed service for storing unstructured data. Store any amount of data and retrieve it as often as you like. More Info - click here! Spring Boot Spring Boot makes it easy to create stand-alone, production-grade Spring-based Applications that you can "just run".  More Info - click here! 2. Create a GCP Project First, Sign into the Google console at  https://console.cloud.google.com . You can create a new project by first selecting the project dropdown in the top left and selecting " New Project ". Next, specify your GCP  Project name  and  Project ID . Then  Click on the " CREATE " button. Copy " Project ID " and keep it for future purposes. 3. Create a Google Cloud Storage bucke...
Read more