Java Spring MongoDB CRUD APIs

Hello World !!

During this time, so many peoples creating APIs and at the same time so many peoples using that APIs on daily basic.

Overview

Today, in this blog we are going to see how to develop REST CRUD APIs using Spring Boot and MongoDB.

We are going to create below mention APIs (methods, urls and action defined in below table)

Method	Urls	Action
POST	/api/user/create	Create New User
GET	/api/user/getAllUser	Get All Users
GET	/api/user/getUser?id=	Get User By ID
PUT	/api/user/update	Update User By ID
DELETE	/api/user/deleteUser?id=	Delete User By ID
DELETE	/api/user/deleteAllUser	Delete All Users

Technology

Java 8
Spring Boot
MongoDB
Maven

Project Structure

User data model class is same as Entity and table User.
UserResponse class is we are using to create API json response format.
UserRepository is an interface that extends MongoRepository for CRUD methods of MongoDB database. This interface is autowired in Service class, according to CRUD methods.
UserService is a class in which UserRepository CRUD methods is used to interact with database and this service class is autowired in UserController class.
UserController class is a RestController, which has all the required RESTful method mapping.
Configuration related to MongoDB is in application.properties.

Create & Setup Spring Boot project

To create spring boot project we can use Spring Online Tool or we can use IDE development tools.

Now, add below mentioned dependency in pom.xml file

Now, using this dependency we are able to interact with MongoDB. But, First we need to define user/database and port number to connect with MongoDB.

Configure MongoDB with Spring Boot

To configure, we need to add/define user/database and port in application.properties file under src/main/resource folder.

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Define Data Model

We are going to use Id, userName, userEmail, userPhone fields in our data model named User.

model/User.java

here, @Document annotation helps us to define collection name as user and @id annotation helps use to generate id column as unique.

Create Repository to interact with MongoDB

In repository package, create UserRepository interface that extends MongoRepository.

repository/UserRepository.java

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Now, using this interface we can use MongoRepository's methods like save(), findById(), findAll(), deleteById(), deleteAll() etc.

Also, we can define our own methods in this interface to interact with database.

Create Service to interact with Repository interface

In service package, create UserService class. In that class we are going to auto-wire UserRepository to use methods from that interface.

service/UserService.java

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In this service class we have created some methods to interact with UserRepository.

Now, we are going to auto-wire this class in controller so we can use this methods as per our need in REST services.

Create Spring REST APIs controller

Now, we need to create basic API controller, after that we are going to add logic in each and every API endpoint.

controller/UserController.java

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Here, we have created some RESTful APIs to work with MongoDB.

Create User

To handle POST HTTP request we are using @PostMapping.

To create new user we need to call API (/api/user/create) using POST method with required json data. Internally, we are calling MongoRepository.save() method to create new user.

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Update User

To handle PUT HTTP request we are using @PutMapping.

To update user we need to call API (/api/user/update) using PUT method with required json data including id. Here also, internally we are calling MongoRepository.save() method to update user information.

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Get User Details

To handle GET HTTP request we are using @GetMapping.

To get user details we are going to follow to methods.

Get All User

To get all user details, we need to call API (/api/user/getAllUser) using GET method. Internally, we are calling MongoRepository.findAll() method.

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Get User By Id

To get user details by id, we need to call API (/api/user/getUser) using GET method with id as a query parameter. Internally, we are calling MongoRepository.findById() method.

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Delete User Details

To handle DELETE HTTP request we are using @DeleteMapping.

To delete user details we are going to follow to methods.

Delete All User

To delete all user details, we need to call API (/api/user/deleteAllUser) using DELETE method. Internally, we are calling MongoRepository.deleteAll() method.

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Delete User By Id

To delete user details by id, we need to call API (/api/user/deleteUser) using DELETE method with id as a query parameter. Internally, we are calling MongoRepository.deleteById() method.

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