CRUD (Create, Read, Update, Delete) operation using Java Spring Boot with PostgreSQL-2025

spring.application.name=java-crud-postgre-sql spring.datasource.url=jdbc:postgresql://localhost:5432/database_name spring.datasource.username=DB user name spring.datasource.password=DB password here spring.datasource.driver-class-name=org.postgresql.Driver spring.jpa.hibernate.ddl-auto=update spring.jpa.show-sql=true spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.PostgreSQLDialect server.port=8080 

package com.example.demo.model; import jakarta.persistence.*; @Entity public class Product { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; private String name; private Double price; // Getters and Setters } 

package com.example.demo.repository; import com.example.demo.model.Product; import org.springframework.data.jpa.repository.JpaRepository; public interface ProductRepository extends JpaRepository<Product, Long> { } 

package com.example.demo.service; import com.example.demo.model.Product; import com.example.demo.repository.ProductRepository; import org.springframework.stereotype.Service; import java.util.List; import java.util.Optional; @Service public class ProductService { private final ProductRepository repo; public ProductService(ProductRepository repo) { this.repo = repo; } public List<Product> getAll() { return repo.findAll(); } public Product save(Product product) { return repo.save(product); } public Optional<Product> getById(Long id) { return repo.findById(id); } public void deleteById(Long id) { repo.deleteById(id); } public Product update(Long id, Product updatedProduct) { return repo.findById(id).map(product -> { product.setName(updatedProduct.getName()); product.setPrice(updatedProduct.getPrice()); return repo.save(product); }).orElseThrow(() -> new RuntimeException("Product not found")); } } 

package com.example.demo.controller; import com.example.demo.model.Product; import com.example.demo.service.ProductService; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; import java.util.List; @RestController @RequestMapping("/api/products") public class ProductController { private final ProductService service; public ProductController(ProductService service) { this.service = service; } @GetMapping public List<Product> getAll() { return service.getAll(); } @GetMapping("/{id}") public ResponseEntity<Product> getById(@PathVariable Long id) { return service.getById(id) .map(ResponseEntity::ok) .orElse(ResponseEntity.notFound().build()); } @PostMapping public Product create(@RequestBody Product product) { return service.save(product); } @PutMapping("/{id}") public Product update(@PathVariable Long id, @RequestBody Product product) { return service.update(id, product); } @DeleteMapping("/{id}") public ResponseEntity<Void> delete(@PathVariable Long id) { service.deleteById(id); return ResponseEntity.noContent().build(); } }