With the increasing demand for Microservices Architecture Patterns in the industry the popularity of Spring Boot is also increasing because when it comes to Microservices Development, Spring Boot is the first choice of every developer. Spring Boot is a microservice-based framework that makes a production-ready application in significantly less time. By using Spring Boot, you can make your microservices smaller and it will run faster. And for this reason, Spring Boot has become the standard for Java microservices. In this article, we will create a simple Microservice using Spring Boot.
Step-by-Step Guide
Step 1: Create a New Spring Boot Project in Spring Initializr
To create a new Spring Boot project, please refer to How to Create a Spring Boot Project in Spring Initializr and Run it in IntelliJ IDEA. For this project choose the following things
- Project: Maven
- Language: Java
- Packaging: Jar
- Java: 17
Please choose the following dependencies while creating the project.
- Spring Boot DevTools
- Spring Data JPA
- MySQL Driver
- Spring Web
Generate the project and run it in IntelliJ IDEA by referring to the above article.
Note: We have used the MySQL database in this project.
Step 2: Create Schema in MySQL Workbench and Put Some Sample Data
Go to your MySQL Workbench and create a schema named gfgmicroservicesdemo and inside that create a table called employee and put some sample data as shown in the below image. Here we have created 4 columns and put some sample data.
- id
- name
- age
Now we are going to fetch Employee Data from Employee Table in our Spring Boot project. To do it refer to the following steps. Before moving to IntelliJ IDEA let’s have a look at the complete project structure for our Microservices.
Step 3: Make Changes in Your application.properties File
Now make the following changes in your application.properties file.
spring.datasource.url=jdbc:mysql://localhost:3306/gfgmicroservicesdemo spring.datasource.username=put your username here spring.datasource.password=put your password here
You may also refer to the below image
Step 4: Create Your Entity/Model Class
Go to the src > main > java > entity and create a class Employee and put the below code. This is our model class.
Java
package com.gfg.employeaap.entity; import jakarta.persistence.*; @Entity@Table(name = "employee")public class Employee { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "id") private int id; @Column(name = "name") private String name; @Column(name = "email") private String email; @Column(name = "age") private String age; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getAge() { return age; } public void setAge(String age) { this.age = age; }} |
Step 5: Create Your Repository Interface
Go to the src > main > java > repository and create an interface EmployeeRepo and put the below code. This is our repository where we write code for all the database-related stuff.
Java
package com.gfg.employeaap.repository; import com.gfg.employeaap.entity.Employee;import org.springframework.data.jpa.repository.JpaRepository; public interface EmployeeRepo extends JpaRepository<Employee, Integer> { } |
Note: Please refer to this article to know more about JpaRepository.
Step 6: Create an EmployeeResponse Class
Go to the src > main > java > response and create a class EmployeeResponse and put the below code.
Java
package com.gfg.employeaap.response; public class EmployeeResponse { private int id; private String name; private String email; private String age; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public String getAge() { return age; } public void setAge(String age) { this.age = age; }} |
Step 7: Create Your Service Class
Go to the src > main > java > service and create a class EmployeeService and put the below code. This is our service class where we write our business logic.
Java
package com.gfg.employeaap.service; import com.gfg.employeaap.entity.Employee;import com.gfg.employeaap.repository.EmployeeRepo;import com.gfg.employeaap.response.EmployeeResponse;import org.modelmapper.ModelMapper;import org.springframework.beans.factory.annotation.Autowired; import java.util.Optional; public class EmployeeService { @Autowired private EmployeeRepo employeeRepo; @Autowired private ModelMapper mapper; public EmployeeResponse getEmployeeById(int id) { Optional<Employee> employee = employeeRepo.findById(id); EmployeeResponse employeeResponse = mapper.map(employee, EmployeeResponse.class); return employeeResponse; } } |
Step 8: Create an Employee Controller
Go to the src > main > java > controller and create a class EmployeeController and put the below code. Here we are going to create an endpoint “/employees/{id}” to find an employee using id.
Java
package com.gfg.employeaap.controller; import com.gfg.employeaap.response.EmployeeResponse;import com.gfg.employeaap.service.EmployeeService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.HttpStatus;import org.springframework.http.ResponseEntity;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RestController; @RestControllerpublic class EmployeeController { @Autowired private EmployeeService employeeService; @GetMapping("/employees/{id}") private ResponseEntity<EmployeeResponse> getEmployeeDetails(@PathVariable("id") int id) { EmployeeResponse employee = employeeService.getEmployeeById(id); return ResponseEntity.status(HttpStatus.OK).body(employee); } } |
Step 9: Create a Configuration Class
Go to the src > main > java > configuration and create a class EmployeeConfig and put the below code.
Java
package com.gfg.employeaap.configuration; import com.gfg.employeaap.service.EmployeeService;import org.modelmapper.ModelMapper;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration; @Configurationpublic class EmployeeConfig { @Bean public EmployeeService employeeBean() { return new EmployeeService(); } @Bean public ModelMapper modelMapperBean() { return new ModelMapper(); } } |
Note: You may refer to these two articles
Before running the Microservice below is the complete pom.xml file. Please cross-verify if you have missed some dependencies
XML
<?xml version="1.0" encoding="UTF-8"?> xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>3.0.2</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.gfg.employeaap</groupId> <artifactId>employee-service</artifactId> <version>0.0.1-SNAPSHOT</version> <name>employee-service</name> <description>Employee Service</description> <properties> <java.version>17</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>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> <optional>true</optional> </dependency> <dependency> <groupId>com.mysql</groupId> <artifactId>mysql-connector-j</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.modelmapper</groupId> <artifactId>modelmapper</artifactId> <version>3.1.1</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> |
Step 10: Run Your Employee Microservice
To run your Employee Microservice src > main > java > EmployeeServiceApplication and click on the Run button. If everything goes well then you may see the following screen in your console. Please refer to the below image.
Step 11: Test Your Endpoint in Postman
Now open Postman and hit the following URL
GET: http://localhost:8080/employees/1
And you can see the following response
{
"id": 1,
"name": "Amiya",
"email": "ar@gmail",
"age": "25"
}
Please refer to the below image.
This is how we have built our Employee Microservice with the help of Java and Spring Boot. And you can also design all your endpoints and write all the business logic, database logic, etc in the corresponding files.
