accountfiledao.java

电子银行系统

package DAO;

import java.util.*;
import java.io.*;
import model.*;

/*
 * 文件DAO的实现,将系统中的所有有用数据信息保存到文件中;
 * saveAccounts(Map map):将传过来的Map中的数据保存到指定(name文件名)的文件中;
 * loadAccounts():以自己的id为key值
 */
class AccountFileDAO implements AccountDAO {

	private String name;

	public AccountFileDAO(String name) {
		super();
		this.name = name;
	}

	public void saveAccounts(HashMap map) {
		ObjectOutputStream out = null;
		try {
			FileOutputStream fos = new FileOutputStream(name);
			out = new ObjectOutputStream(fos);
			
			Collection c = map.values();
			Iterator it = c.iterator();
			if (it.hasNext()) {
				Account a = (Account) it.next();
				out.writeObject(a);
			}
		} catch (FileNotFoundException e) {
			// e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				if (out != null)
					out.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}

	public HashMap loadAccounts() {
		HashMap map = null;
		ObjectInputStream in = null;
		try {
			map = new HashMap();
			FileInputStream fin = new FileInputStream(name);
			in = new ObjectInputStream(fin);
			while (true) {
				Account ac = (Account) in.readObject();
				map.put(new Long(ac.getId()), ac);
			}
		} catch (FileNotFoundException e) {
			// e.printStackTrace();
		} catch (IOException e) {
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} finally {
			try {
				if (in != null)
					in.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return map;
	}
}