[Spring Boot] DAO 생성

0. DAO

 

DAO는 Data Access Object라는 뜻으로, DB와 데이터를 연결하기 위한 클래스이다. Service에서 비즈니스 로직을 처리한 후 DAO에서 데이터를 받아 Repository를 통해 DB에 작업을 수행한다.

 

 

1. ProductDAO

 

package com.web.springtest00.data.dao;

import com.web.springtest03.data.entity.Product;

public interface ProductDAO {
    
    Product insertProduct(Product prodcut);

    Product selectProduct(Long number);

    Product updateProductName(Long number, String name) throws Exception;

    void deleteProduct(Long number) throws Exception;
    
}

 

 

2. ProductDAOImpl

 

package com.web.springtest00.data.dao.impl;

import java.time.LocalDateTime;
import java.util.Optional;

import org.springframework.stereotype.Component;

import com.web.springtest00.data.dao.ProductDAO;
import com.web.springtest00.data.entity.Product;
import com.web.springtest00.data.repository.ProductRepository;

@Component
public class ProductDAOImpl implements ProductDAO {

    private final ProductRepository productRepository;

    public ProductDAOImpl (ProductRepository productRepository){
        this.productRepository = productRepository;
    }

    @Override
    public Product insertProduct(Product prodcut) {
        return productRepository.save(prodcut);
    }

    @Override
    public Product selectProduct(Long number) {
        return productRepository.findById(number).orElse(null);
    }

    @Override
    public Product updateProductName(Long number, String name) throws Exception {

        Optional<Product> selectedProduct = productRepository.findById(number);
        Product updatedProduct;
        if(selectedProduct.isPresent()){
            Product product = selectedProduct.get();
            product.setName(name);
            product.setUpdatedAt(LocalDateTime.now());
            updatedProduct = productRepository.save(product);
        } else {
            throw new Exception();
        }
        return updatedProduct;
    }

    @Override
    public void deleteProduct(Long number) throws Exception {
        Optional<Product> selectedProduct = productRepository.findById(number);
        if(selectedProduct.isPresent()){
            Product product = selectedProduct.get();
            productRepository.delete(product);
        } else { 
            throw new Exception();
        }
    }

}