planemodeldaofromfile.java

一个很详细的航空售票系统开发的例子

package com.tarena.abs.dao;

import java.util.*;
import java.io.*;
import com.tarena.abs.model.*;

public class PlaneModelDAOFromFile implements PlaneModelDAO {
/*
	public Set getAllPlaneModel() {
		// TODO Auto-generated method stub
		return null;
	}

	public boolean addPlaneModel(PlaneModel plane) {
		// TODO Auto-generated method stub
		return false;
	}

	public boolean removePlaneModel(String model) {
		// TODO Auto-generated method stub
		return false;
	}
*/
	
	
	private File file;
	
	public PlaneModelDAOFromFile(File file) {
		this.file=file;
		OutputStream out=null;
		ObjectOutputStream oos=null;
		try {
			if(!(file.length()>0)){
				out=new FileOutputStream(file);
				oos=new ObjectOutputStream(out);
				oos.writeObject(new HashSet());
				oos.flush();
			}
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			if(oos!=null)try{oos.close();}catch(IOException e){}
			if(out!=null)try{out.close();}catch(IOException e){}
		}
	}
	
	public boolean addPlaneModel(PlaneModel plane) {
		HashSet hs=null;
		InputStream in=null;
		ObjectInputStream ois=null;
		OutputStream out=null;
		ObjectOutputStream oos=null;
		boolean success=false;
		try {
			in=new FileInputStream(file);
			ois=new ObjectInputStream(in);
			hs=(HashSet)ois.readObject();
			if(hs==null){
				hs=new HashSet();
			}
			success=hs.add(plane);
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			if(ois!=null)try{ois.close();}catch(IOException e){}
			if(in!=null)try{in.close();}catch(IOException e){}
		}
		
		try {
			out=new FileOutputStream(file);
			oos=new ObjectOutputStream(out);
			oos.writeObject(hs);
			oos.flush();
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			if(oos!=null)try{oos.close();}catch(IOException e){}
			if(out!=null)try{out.close();}catch(IOException e){}
		}
		return success;
	}

	public Set getAllPlaneModel() {
		HashSet hs=null;
		InputStream in=null;
		ObjectInputStream ois=null;
		try {
			in=new FileInputStream(file);
			ois=new ObjectInputStream(in);
			hs=(HashSet)ois.readObject();
			return hs;
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			if(ois!=null)try{ois.close();}catch(IOException e){}
			if(in!=null)try{in.close();}catch(IOException e){}
		}
		return null;
	}

	public boolean removePlaneModel(String model) {
		// TODO Auto-generated method stub
		return false;
	}
}