Product 예제 4

※ com.my.product.dao.ProductDAOFile 작성하기

ex) 파일명 : D:\products.txt

파일구조

#상품번호값:상품명값:상품가격값

C0001:아메리카노:1000

C0002:아이스아메리카노:1000

인터페이스 바로 삽입하기

package com.my.product.dao;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import com.my.exception.AddException;
import com.my.exception.FindException;
import com.my.exception.ModifyException;
import com.my.exception.RemoveException;
import com.my.product.dto.Product;

public class ProductDAOFile implements ProductDAOInterface {
	private String fileName = "D:\\products.txt";
	
	public ProductDAOFile() {
		createFile();
	}
	
	private void createFile() {
		File file = new File(fileName);
		if(!file.exists()) {
			try {
				file.createNewFile();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	
	
	
	@Override
	public void insert(Product product) throws AddException {
		try {
			selectByProdNo(product.getProdNo());
			throw new AddException("이미 존재하는 상품입니다");
		} catch (FindException e) {
//			e.printStackTrace();
			FileWriter fw = null;
			try {
				fw = new FileWriter(fileName, true);	// 기존 파일 끝에 append
				String prodStr = product.getProdNo() + ":" + product.getProdName() + ":" + product.getProdPrice() + "\n";
				fw.write(prodStr);
			} catch (IOException e1) {
				e1.printStackTrace();
			} finally {
				if(fw != null) {
					try {
						fw.close();
					} catch (IOException e1) {
					}
				}
			}
		}
	}


	@Override
	public Product selectByProdNo(String no) throws FindException {
		Scanner sc = null;
		try {
			sc = new Scanner(new FileInputStream(fileName));
			while(sc.hasNextLine()) {
				String line = sc.nextLine(); // 한줄로 읽어옴
				String[] arr = line.split(":");
				String prodNo = arr[0];
				if(prodNo.equals(no) ) {
					return new Product(prodNo, arr[1], Integer.parseInt(arr[2]));
				}
			}
			 throw new FindException("번호에 해당하는 상품이 없습니다");
		} catch (FileNotFoundException e) {
			e.printStackTrace();
			createFile();
			throw new FindException("번호에 해당하는 상품이 없습니다");
		} finally {
			if(sc !=null) {
				sc.close();
			}
		}
	}

	@Override
	public Object selectAll() throws FindException {
		List<Product> all = new ArrayList<>();
		Scanner sc = null;
		try {
//			Scanner sc = new Scanner(new File(fileName)); // 이거 써도 됨
			sc = new Scanner(new FileInputStream(fileName));
			while(sc.hasNextLine()) {
				String line = sc.nextLine();
				String[] arr = line.split(":");
				String prodNo = arr[0];
				String prodName = arr[1];
				int prodPrice = Integer.parseInt(arr[2]);
				Product p = new Product(prodNo, prodName, prodPrice);
				all.add(p);		
			}
			if(all.size() == 0) {
				throw new FindException("상품이 하나도 없습니다");
			}
			return all;
		} catch (FileNotFoundException e) {
			e.printStackTrace();
			createFile();
			throw new FindException("상품이 하나도 없습니다");
		} finally {
			if(sc != null) {
				sc.close();
			}
		}
	}

	@Override
	public void update(Product p) throws ModifyException {
		FileWriter fw = null;
		try {
			List<Product> all = (List)selectAll();
			boolean updated = false;
			for(Product savedP : all) {
				if(savedP.equals(p)) { // if(savedP.getProdNo().equals(p.getProdNo())); {
					if(p.getProdName() != null) {
						savedP.setProdName(p.getProdName());
						updated = true;
					}
					if(p.getProdPrice() != 0) {
						savedP.setProdPrice(p.getProdPrice());
						updated = true;
					}
					break;
				}
			}
			if(updated) {
				fw = new FileWriter(fileName);
				for(Product savedP : all) {
					String pStr = savedP.getProdNo() + ":" + savedP.getProdName() + ":" + savedP.getProdPrice() + "\n";
					fw.write(pStr);
					}
				}
		} catch (FindException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if(fw != null) {
				try {
					fw.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}

	@Override
	public void delete(String prodNo) throws RemoveException {
		FileWriter fw = null;
		try {
			List<Product> all = (List)selectAll();
			/* 이렇게 써도 됨
			Product savedP = new Product();
			savedP.setProdNo(prodNo);
			all.remove(saveP);
			*/
			fw = new FileWriter(fileName);	// fileName, true 이거 아님
//			fw = new FileWriter(fileName, false); // 가능
			for(Product p : all) {
				if(!p.getProdNo().equals(prodNo)) {
					String pStr = p.getProdNo() + ":" + p.getProdName() + ":" + p.getProdPrice() + "\n";
					fw.write(pStr);
				}
			}
		} catch (FindException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if(fw != null) {
				try {
					fw.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
		
	}
}

결과