To follow the instructions in this tutorial, you need to switch to the branch api.
main- This branch contains the initial code for the application.api- This branch contains the restful API for the application.api-static- This branch contains the initial version of the restful API for the application.
I use mvn clean spring-boot:run to run the application. Alternatively, you can run the application from your IDE, or build the application and run the jar file from your terminal or deploy to a web server.
The base url for the application is http://localhost:8080/employees
- Static endpoint to get employees:
http://localhost:8080/employees/all - Endpoint to get employees from the database:
http://localhost:8080/employees/employees - Endpint to add an employee:
http://localhost:8080/employees/add
spring.datasource.url=jdbc:h2:./data/test
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=password
spring.jpa.hibernate.ddl-auto=update
spring.jpa.database-platform=org.hibernate.dialect.H2DialectMain class is com.example.demo.DemoApplication
Add a controller empty class com.example.demo.controller.EmployeeController
I ask Copilot to suggest the code for the controller and it suggested the following code: This is the first version of API
// create a new controller class called EmployeeController
// and annotate it with @RestController
// add RequestMapping to /employees
package com.example.demo.controller;
import java.util.ArrayList;
import java.util.List;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
public class EmployeeController {
@RequestMapping("/employees")
@GetMapping
public List<String> getEmployees() {
List<String> employees = new ArrayList<String>();
employees.add("John");
employees.add("Jane");
employees.add("Jack");
employees.add("Jill");
return employees;
}
}You can find this version of api in the branch api-static.
We will improve our API to get data from the database. To do so, we will ask Copilot to suggeest the code for Employee entity, EmployeeRepository.
First create a class in com.example.demo.model package called Employee and ask Copilot to suggest the code for the class. There are 2 ways to ask Copilot to suggest the code for the class: Chat or inline suggestions. I used chat to ask Copilot to suggest the code for the class.
This is my question to Copilot:
create an entity class Employee using lombok
"@Data: generate getters and setters
@AllArgsConstructor: generate constructor with all fields
@NoArgsConstructor: generate constructor with no fields
@Entity: mark this class as an entity class
@Table: map this class to a table named employees
@Id: mark this field as the primary key
@GeneratedValue: generate the value for this field automatically
@Column: map this field to a column named id
@Column: map this field to a column named name
@Column: map this field to a column named email
"
This is the code suggested by Copilot:
import lombok.Data;
import lombok.AllArgsConstructor;
import lombok.NoArgsConstructor;
import javax.persistence.Entity;
import javax.persistence.Table;
import javax.persistence.Id;
import javax.persistence.GeneratedValue;
import javax.persistence.Column;
@Data
@AllArgsConstructor
@NoArgsConstructor
@Entity
@Table(name = "employees")
public class Employee {
@Id
@GeneratedValue
@Column(name = "id")
private Long id;
@Column(name = "name")
private String name;
@Column(name = "email")
private String email;
// adding this constructor to create an instance of the class with the name and email fields
// this is suggested by Copilot after copying the code above
public Employee(String name, String email) {
this.name = name;
this.email = email;
}
}Create a new class EmployeeRepository in the package com.example.demo.repository and ask Copilot to suggest the code for the class. This is the question I asked Copilot:
create EmployeeRepository JPA repository interface manging Employee entity class in the same package
This is the code suggested by Copilot:
mport org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
@Repository
public interface EmployeeRepository extends JpaRepository<Employee, Long> {
}Now we need to include the repository in the controller. I asked Copilot to suggest the code for the controller. This is the question I asked Copilot:
create a new method in the EmployeeController to get all employees from the database using the EmployeeRepository
This is the code suggested by Copilot: (in-line suggestion)
@Autowired
private EmployeeRepository employeeRepository;
@GetMapping("/employees")
public List<Employee> getAllEmployees() {
return employeeRepository.findAll();
}I asked Copilot to suggest the code for the controller to add a new employee. This is the question I asked Copilot:
// Create a new endpoint to add a new employee to the database endpoint is /add
// The method should accept an HTTP POST request and a request body of type Employee
// The method should return the added employee
@PostMapping("/add")
public Employee addEmployee(@RequestBody Employee employee) {
return employeeRepository.save(employee);
}here is the curl command to add a new employee:
curl --location 'http://localhost:8080/employees/add' \
--header 'Content-Type: application/json' \
--data-raw '{
"name": "siavash",
"email": "[email protected]"
}'You can list all employees from database using the following curl command:
curl --location --request GET 'http://localhost:8080/employees/employees'I asked Copilot to suggest the code for the controller to list a single employee. This is the question I asked Copilot:
// Create a new endpoint to get a single employee from the database by id path: /employees/{id}
// The endpoint should accept an HTTP GET request and a path variable of type Long
// The endpoint should return the employee with the given id
@GetMapping("/{id}")
public Employee getEmployeeById(@PathVariable Long id) {
return employeeRepository.findById(id).orElse(null);
}I asked Copilot to suggest the code for the controller to update an employee. This is the question I asked Copilot:
// Create a new endpoint to update an employee in the database by id path: /employees/{id}
// The endpoint should accept an HTTP PUT request, a path variable of type Long, and a request body of type Employee
// The endpoint should return the updated employee
@PutMapping("/{id}")
public Employee updateEmployee(@PathVariable Long id, @RequestBody Employee employee) {
Employee existingEmployee = employeeRepository.findById(id).orElse(null);
if (existingEmployee != null) {
existingEmployee.setName(employee.getName());
existingEmployee.setEmail(employee.getEmail());
return employeeRepository.save(existingEmployee);
}
return null;
}Curl command to update an employee:
curl --location --request PUT 'http://localhost:8080/employees/1' \
--header 'Content-Type: application/json' \
--data-raw '{
"name": "john",
"email": "[email protected]"
}'I asked Copilot to suggest the code for the controller to delete an employee. This is the question I asked Copilot:
// Create a new endpoint to delete an employee from the database by id path: /employees/{id}
// The endpoint should accept an HTTP DELETE request and a path variable of type Long
// The endpoint should return the deleted employee
@DeleteMapping("/{id}")
public Employee deleteEmployee(@PathVariable Long id) {
Employee existingEmployee = employeeRepository.findById(id).orElse(null);
if (existingEmployee != null) {
employeeRepository.delete(existingEmployee);
return existingEmployee;
}
return null;
}Curl command to delete an employee:
curl --location --request DELETE 'http://localhost:8080/employees/1'