Spring Boot CRUD REST API Project using IntelliJ IDEA | Postman | MySQL

Spring Boot CRUD REST API Project using IntelliJ IDEA | Postman | MySQL

Here we will build Spring Boot CRUD REST API Project using IntelliJ IDEA as our IDE. We will use the Postman client to test the REST APIs. We will use Spring Data JPA to develop a repository layer and MySQL database at the backend.

1. 1. Create Spring boot application

      Spring Boot provides a web tool called Spring Initializer to bootstrap an application quickly. Just go to https://start.spring.io/ and generate a new spring boot project.

      Use the below details in the Spring boot creation:

      Project Name:

      springboot-backend

      Project Type:

      Maven

      Choose dependencies:

      Spring Web, Lombok, Spring Data JPA, and MySQL Driver

      Package name:

      net.ducat.springboot

      Packaging:

      Jar

      Download Spring Boot project as a zip file, unzip it, and import it into IntelliJ IDEA.

      Here is the pom.xml file for your reference:

      < ?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>2.5.5< /version>
      < relativePath/>< !-- lookup parent from repository -->
      < /parent>
      < groupId>net.ducat< /groupId>
      < artifactId>springboot-backend< /artifactId>
      < version>0.0.1-SNAPSHOT< /version>
      < name>springboot-backend< /name>
      < description>Demo project for Spring Boot REST APIs< /description>
      < properties>
      < java.version>11< /java.version>
      < /properties>
      < dependencies>
      < 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>mysql< /groupId>
      < artifactId>mysql-connector-java< /artifactId>
      < scope>runtime< /scope>
      < /dependency>
      < dependency>
      < groupId>org.projectlombok< /groupId>
      < artifactId>lombok< /artifactId>
      < optional>true< /optional>
      < /dependency>
      < dependency>
      < groupId>org.springframework.boot< /groupId>
      < artifactId>spring-boot-starter-test< /artifactId>
      < scope>test< /scope>
      < /dependency>
      < /dependencies>
      < build>
      < plugins>
      < plugin>
      < groupId>org.springframework.boot< /groupId>
      < artifactId>spring-boot-maven-plugin< /artifactId>
      < configuration>
      < excludes>
      < exclude>
      < groupId>org.projectlombok< /groupId>
      < artifactId>lombok< /artifactId>
      < /exclude>
      < /excludes>
      < /configuration>
      < /plugin>
      < /plugins>
      < /build>
      < /project>
      

   2. Create Project or Packaging Structure

      create a project or packaging structure for your Spring boot project:

   3. Configure MySQL Database

      Since we’re using MySQL as our database, we need to configure the database URL, username, and password so that Spring can establish a connection with the database on startup. Open src/main/resources/application.properties file and add the following properties to it:

      	spring.datasource.url=jdbc:mysql://localhost:3306/ems?useSSL=false
      	spring.datasource.username=root
      	spring.datasource.password=Mysql@123
      
      	spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
      
      	spring.jpa.hibernate.ddl-auto = update
      

Don’t forget to change the spring.datasource.username and spring.datasource.password as per your MySQL installation. Also, create a database named ems in MySQL before proceeding to the next section.

You don’t need to create any tables. The tables will automatically be created by Hibernate from the Employee entity that we will define in the next step. This is made possible by the property spring.jpa.hibernate.ddl-auto = update.

1. Create JPA Entity

   Go to model package, create a class named Employee and add the following content into it:

   	packagenet.ducat.springboot.model;
   
   	importlombok.AllArgsConstructor;
   	importlombok.Getter;
   	importlombok.NoArgsConstructor;
   	importlombok.Setter;
   
   	importjavax.persistence.*;
   
   	@Getter
   	@Setter
   	@NoArgsConstructor
   	@AllArgsConstructor
   	@Entity
   	@Table(name = "employees")
   	publicclassEmployee{
   
   	@Id
   	@GeneratedValue(strategy = GenerationType.IDENTITY)
   	private long id;
   
   	@Column(name = "first_name")
   	private String firstName;
   
   	@Column(name = "last_name")
   	private String lastName;
   
   	@Column(name = "email_id")
   	private String emailId;
   	}
   

2. Create Spring Data JPA Repository

   No, we gonna create a Spring Data JPA repository to talk with the MySQL database.

   Go to repository package, create the following EmployeeRepository interface and add the following content to it:

   	packagenet.ducat.springboot.repository;
   
   	importnet.ducat.springboot.model.Employee;
   	importorg.springframework.data.jpa.repository.JpaRepository;
   	importorg.springframework.stereotype.Repository;
   
   	publicinterfaceEmployeeRepositoryextendsJpaRepository<Employee, Long>{
   	// all crud database methods
   	}
   

3. Create ResourceNotFoundException Custom Exception

   Go to an exception package, create a class named ResourceNotFoundException and add the following content to it:

   	packagenet.ducat.springboot.exception;
   
   	importorg.springframework.http.HttpStatus;
   	importorg.springframework.web.bind.annotation.ResponseStatus;
   
   	@ResponseStatus(value = HttpStatus.NOT_FOUND)
   	publicclassResourceNotFoundExceptionextendsRuntimeException{
   
   	publicResourceNotFoundException(String message){
   	super(message);
   	    }
   	}
   

4. Creating Spring Boot CRUD REST APIs

   Go to controller package, create a class named EmployeeController and add the following content to it:

   	packagenet.ducat.springboot.controller;
   
   	import net.ducat.springboot.exception.ResourceNotFoundException;
   	import net.ducat.springboot.model.Employee;
   	import net.ducat.springboot.repository.EmployeeRepository;
   	importorg.springframework.beans.factory.annotation.Autowired;
   	importorg.springframework.http.HttpStatus;
   	importorg.springframework.http.ResponseEntity;
   	importorg.springframework.web.bind.annotation.*;
   
   	importjava.util.List;
   
   	@CrossOrigin("*")
   	@RestController
   	@RequestMapping("/api/v1/employees")
   	publicclassEmployeeController{
   
   	@Autowired
   	privateEmployeeRepositoryemployeeRepository;
   
   	@GetMapping
   	public List< Employee>getAllEmployees(){
   	returnemployeeRepository.findAll();
   	    }
   
   	// build create employee REST API
   	@PostMapping
   	public Employee createEmployee(@RequestBody Employee employee){
   	returnemployeeRepository.save(employee);
   	    }
   
   	// build get employee by id REST API
   	@GetMapping("{id}")
   	publicResponseEntity< Employee>getEmployeeById(@PathVariablelong id){
   	        Employee employee = employeeRepository.findById(id)
   	                .orElseThrow(() ->newResourceNotFoundException("Employee not exist with id:" + id));
   	returnResponseEntity.ok(employee);
   	    }
   
   	// build update employee REST API
   	@PutMapping("{id}")
   	publicResponseEntity< Employee>updateEmployee(@PathVariablelong id,@RequestBody Employee employeeDetails){
   	        Employee updateEmployee = employeeRepository.findById(id)
   	                .orElseThrow(() ->newResourceNotFoundException("Employee not exist with id: " + id));
   
   	updateEmployee.setFirstName(employeeDetails.getFirstName());
   	updateEmployee.setLastName(employeeDetails.getLastName());
   	updateEmployee.setEmailId(employeeDetails.getEmailId());
   
   	employeeRepository.save(updateEmployee);
   
   	returnResponseEntity.ok(updateEmployee);
   	    }
   
   	// build delete employee REST API
   	@DeleteMapping("{id}")
   	publicResponseEntity< HttpStatus>deleteEmployee(@PathVariablelong id){
   
   	        Employee employee = employeeRepository.findById(id)
   	                .orElseThrow(() ->newResourceNotFoundException("Employee not exist with id: " + id));
   
   	employeeRepository.delete(employee);
   
   	returnnewResponseEntity< >(HttpStatus.NO_CONTENT);
   
   	    }
   	}
   
   	Get All Employees REST API:
   	@GetMapping
   	public List< Employee>getAllEmployees(){
   	returnemployeeRepository.findAll();
   	    }
   
   

   Create Employee REST API:

   	// build create employee REST API
   	@PostMapping
   	public Employee createEmployee(@RequestBody Employee employee) {
   	returnemployeeRepository.save(employee);
   	    }
   

   Get Employee by Id REST API:

   	// build get employee by id REST API
   	@GetMapping("{id}")
   	publicResponseEntity< Employee>getEmployeeById(@PathVariable  long id){
   	Employee employee = employeeRepository.findById(id)
   	.orElseThrow(() ->newResourceNotFoundException("Employee not exist with id:" + id));
   	returnResponseEntity.ok(employee);
   	    }
   

   Update Employee REST API:

   	// build update employee REST API
   	@PutMapping("{id}")
   	publicResponseEntity< Employee>updateEmployee(@PathVariablelong id,@RequestBody Employee employeeDetails){
   	Employee updateEmployee = employeeRepository.findById(id)
   	.orElseThrow(() ->newResourceNotFoundException("Employee not exist with id: " + id));
   
   	updateEmployee.setFirstName(employeeDetails.getFirstName());
   	updateEmployee.setLastName(employeeDetails.getLastName());
   	updateEmployee.setEmailId(employeeDetails.getEmailId());
   
   	employeeRepository.save(updateEmployee);
   
   	returnResponseEntity.ok(updateEmployee);
   	    }
   
   

   Delete Employee REST API:

   	// build delete employee REST API
   	@DeleteMapping("{id}")
   	publicResponseEntity< HttpStatus>deleteEmployee(@PathVariable long id){
   
   	Employee employee = employeeRepository.findById(id)
   	.orElseThrow(() ->newResourceNotFoundException("Employee not exist with id: " + id));
   
   	employeeRepository.delete(employee);
   
   	returnnewResponseEntity< >(HttpStatus.NO_CONTENT);
   
   	    }
   
   

5. Running the Application

   We have successfully developed all the CRUD Rest APIs for the Employee model. Now it’s time to deploy our application in a servlet container(embedded tomcat).

   Two ways we can start the standalone Spring boot application.

   1. 1. From the root directory of the application and type the following command to run it –

   $ mvnspring-boot:run

   1. From your IDE, run the SpringbootBackendApplication.main() method as a standalone Java class that will start the embedded Tomcat server on port 8080 and point the browser to http://localhost:8080/.

6. Testing CRUD REST APIs using Postman

   Test Get All Employees REST API:

   

   Test Create Employee REST API:

   

   Test Get Employee By Id REST API:

   

   Test Update Employee REST API:

   

   Test Delete Employee REST API:

   

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