daoimpl.java

一个简单的银行系统

package dao;
import java.io.*;
import java.util.*;
import entity.*;
import exception.*;

public class DaoImpl implements AccountDao{
		
	public void deleteAccount(long id)  {
			File file=new File("account");
			File[] l=file.listFiles();
			for(File f:l){
				if(f.getName().startsWith(Long.toString(id)));
				f.delete();
			}
		
	}

	public Account getAccountById(long id) throws Exception{
		File file=new File("account");
		File[] l=file.listFiles();
		FileInputStream fis=null;
		ObjectInputStream ois=null;
		Account a=null;
		for(File f:l){
			if(f.getName().startsWith(Long.toString(id))){
			try {
				fis = new FileInputStream(f);
				ois = new ObjectInputStream(fis);
				a = (Account) ois.readObject();
				return a;
			} 
			finally{
				if(ois!=null)
					try {
						ois.close();
					} catch (IOException e) {
						e.printStackTrace();
					}
			}
			}
		}
		
		return null;
	}

	public List getAccountByPersonId(String personId) throws Exception{
		File file=new File("account");
		File[] l=file.listFiles();
		FileInputStream fis=null;
		ObjectInputStream ois=null;
		Account a=null;
		List list=new ArrayList();
		for(File f:l){
			fis = new FileInputStream(f);
			ois = new ObjectInputStream(fis);
			a = (Account) ois.readObject();
			if(a.getPersonId().equals(personId)){
				list.add(a);
			}
		}
		if(ois!=null) ois.close();
		return list;
	}

	public void insertAccount(Account c)throws Exception {
		File file=new File("account");
		if(!file.exists()) file.mkdir();
		File[] l=file.listFiles();
		FileOutputStream fos=new FileOutputStream("account\\"+c.getCardId()+".dat");
		ObjectOutputStream os=new ObjectOutputStream(fos);
		os.writeObject(c);
		if(os!=null) os.close();
	}

	public void updateAcccount(Account c) throws Exception{
		FileOutputStream fos=new FileOutputStream("account\\"+c.getCardId()+".dat");
		ObjectOutputStream os=new ObjectOutputStream(fos);
		os.writeObject(c);
		if(os!=null) os.close();
		
	}

	public long findLastId() throws Exception{
		// TODO Auto-generated method stub
		FileOutputStream fos=null;
		DataOutputStream dos=null;
		FileInputStream fis=null;
		DataInputStream dis=null;
		File file =new File("id.dat");
		Account a=null;
		if (!file.exists()) {
			file.createNewFile();
			long id=100001;
			fos=new FileOutputStream(file);
			dos=new DataOutputStream(fos);
			dos.writeLong(id);
			dos.close();
			return id;
		}else{
			fis=new FileInputStream(file);
			dis=new DataInputStream(fis);
			long id=dis.readLong();
			id++;
			return id;
		}
	}
}