Spring Boot & H2 - Get Record

Let's now update the project created so far to prepare a complete Get Record API and test it.

Update Service

// Use repository.findById() to get Employee entity by Id
public Employee getEmployeeById(int id) {
   return repository.findById(id).get();
}

EmployeeService

package com.tutorialspoint.service;

import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.tutorialspoint.entity.Employee;
import com.tutorialspoint.repository.EmployeeRepository;

@Service
public class EmployeeService {

   @Autowired
   EmployeeRepository repository;

   // get an employee by ud
   public Employee getEmployeeById(int id) {
      return repository.findById(id).get();
   }

   // to be implemented
   public List<Employee> getAllEmployees(){
      return null;
   }

   // create or update an employee
   public void saveOrUpdate(Employee employee) {
      repository.save(employee);
   }

   // to be implemented
   public void deleteEmployeeById(int id) {
   }
}

Update Controller

// Use service.getEmployeeById() to get Employee entity from database
@GetMapping("/employee/{id}")
public Employee getEmployee(@PathVariable("id") int id) {
   return employeeService.getEmployeeById(id);
}

EmployeeController

package com.tutorialspoint.controller;

import java.util.List;
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.tutorialspoint.entity.Employee;
import com.tutorialspoint.service.EmployeeService;

@RestController
@RequestMapping(path = "/emp")
public class EmployeeController {

   @Autowired
   EmployeeService employeeService;

   // to be implemented
   @GetMapping("/employees")
   public List<Employee> getAllEmployees(){
      return null;
   }

   // get an employee by id
   @GetMapping("/employee/{id}")
   public Employee getEmployee(@PathVariable("id") int id) {
      return employeeService.getEmployeeById(id);
   }

   // to be implemented
   @DeleteMapping("/employee/{id}")
   public void deleteEmployee(@PathVariable("id") int id) {
   }

   // create an employee
   @PostMapping("/employee")
   public void addEmployee(@RequestBody Employee employee) {
      employeeService.saveOrUpdate(employee);   
   }

   // to be implemented
   @PutMapping("/employee")
   public void updateEmployee(@RequestBody Employee employee) {
   }	
}

Run the application

In eclipse, run the Employee Application configuration as prepared during Application Setup

Eclipse console will show the similar output.

[INFO] Scanning for projects...
...
2024-08-21T15:01:29.377+05:30  INFO 14180 --- [springboot-h2] [  restartedMain] o.s.b.d.a.OptionalLiveReloadServer       : LiveReload server is running on port 35729
2024-08-21T15:01:29.426+05:30  INFO 14180 --- [springboot-h2] [  restartedMain] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port 8080 (http) with context path '/'
2024-08-21T15:01:29.434+05:30  INFO 14180 --- [springboot-h2] [  restartedMain] c.t.s.SpringbootH2Application            : Started SpringbootH2Application in 6.729 seconds (process running for 7.28)

Once server is up and running, Use Postman to make a POST request −

Set the following parameters in POSTMAN.

• HTTP Method − POST

• URL − http://localhost:8080/emp/employee

• BODY − An employee JSON

{  
   "id": "1",  
   "age": "35",  
   "name": "Julie",  
   "email": "julie@gmail.com"  
}   

Click on Send Button and check the response status to be OK.

Now make a GET Request to get that record.

Set the following parameters in POSTMAN.

• HTTP Method − GET

• URL − http://localhost:8080/emp/employee/1

Click the send button and verify the response.