agentdaofromfile.java

一套基于JAVA开发的完整版航空订票系统,代码简洁,适合JAVA初学者研究

package com.tarena.abs.dao;

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

import com.tarena.abs.model.Agent;

public class AgentDaoFromFile implements AgentDAO {

private File file;
	
public AgentDaoFromFile(File flie){
	this.file = flie;
	FileOutputStream fos=null;
	ObjectOutputStream oos=null;
	FileInputStream fis=null;
	ObjectInputStream ois=null;
	Object obj=null;
	
	try {//试着读取文件中的对象
		fis=new FileInputStream(file);
		ois=new ObjectInputStream(fis);
		obj=ois.readObject();
	} catch (Exception e) {
		System.out.println("agent.dat文件中目前还没有数据，将写入一个空数据！");
	}finally{
		if(ois!=null)try{ois.close();}catch(IOException e){}
		if(fis!=null)try{fis.close();}catch(IOException e){}
	}
	
	//如果读到的对象为null，或者不是HashSet
	if(obj==null || !(obj instanceof HashSet)){
		try {//就向文件中写入一个空的HashSet
			fos=new FileOutputStream(file);
			oos=new ObjectOutputStream(fos);
			oos.writeObject(new HashSet());
			oos.flush();
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			if(oos!=null)try{oos.close();}catch(IOException e){}
			if(fos!=null)try{fos.close();}catch(IOException e){}
		}
	}
}
	
	public Agent getAgent(String name, String passwd) {
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		HashSet hs = new HashSet();
		try {
			fis = new FileInputStream(file);
			ois = new ObjectInputStream(fis);
			hs = (HashSet)ois.readObject();
			ois.close();
			fis.close();
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		Iterator it = hs.iterator();
		while(it.hasNext()){
			Agent a = (Agent)it.next();
			if(a.getName().equals(name)&& a.getPasswd().equals(passwd)){
				return a;
			}
		}
		return null;
	}

	@SuppressWarnings("unchecked")
	public boolean addAgent(Agent user) {
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		HashSet hs = new HashSet();
		try {
			fis = new FileInputStream(file);
			ois = new ObjectInputStream(fis);
			hs = (HashSet)ois.readObject();//从文件中读取对象
			ois.close();//关闭文件输入流
			fis.close();
			hs.add(user);//集合中添加一个对象
			ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
			oos.writeObject(hs);//把集合对象从新写入文件中
			oos.flush();
			oos.close();
			
		} catch (Exception e) {
			return false;
		}
		return true;
	}

	public boolean removeAgent(String name) {
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		HashSet hs = new HashSet();
		try {
			fis = new FileInputStream(file);
			ois = new ObjectInputStream(fis);
			hs = (HashSet)ois.readObject();
			ois.close();
			fis.close();
			
		} catch (Exception e) {
			return false;
		}
		Iterator it = hs.iterator();
		while(it.hasNext()){
			Agent a = (Agent)it.next();
			if(a.getName().equals(name)){
				hs.remove(a);
				try {
					ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
					oos.writeObject(hs);
					oos.flush();
					oos.close();
				}catch (IOException e) {
					return false;
				}
				return true;
			}
		}
		return false;
	}

	public Agent updateScore(String name, int n) {
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		HashSet hs = new HashSet();
		try {
			fis = new FileInputStream(file);
			ois = new ObjectInputStream(fis);
			hs = (HashSet)ois.readObject();
			ois.close();
			fis.close();
			
		} catch (Exception e) {
			return null;
		}
		Iterator it = hs.iterator();
		while(it.hasNext()){
			Agent a = (Agent)it.next();
			if(a.getName().equals(name)){
				a.setScore(a.getScore()+n);
				try {
					ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
					oos.writeObject(hs);
					oos.flush();
					oos.close();
				}catch (IOException e) {
					return null;
				}
				return a;
			}
		}
		return null;
	}

	public boolean modifyPassword(String name, String oldPassword,
			String newPassword) {
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		HashSet hs = new HashSet();
		try {
			fis = new FileInputStream(file);
			ois = new ObjectInputStream(fis);
			hs = (HashSet)ois.readObject();
			ois.close();
			fis.close();
			
		} catch (Exception e) {
			return false;
		}
		Iterator it = hs.iterator();
		while(it.hasNext()){
			Agent a = (Agent)it.next();
			if(a.getName().equals(name) && a.getPasswd().equals(oldPassword)){
				a.setPasswd(newPassword);
				try {
					ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file));
					oos.writeObject(hs);
					oos.flush();
					oos.close();
				}catch (IOException e) {
					return false;
				}
				return true;
			}
		}
		return false;
	}

	public Set getAllAgent() {
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		HashSet hs = new HashSet();
		try {
			fis = new FileInputStream(file);
			ois = new ObjectInputStream(fis);
			hs = (HashSet)ois.readObject();
			ois.close();
			fis.close();
			
		} catch (Exception e) {
			return null;
		}
		return hs;
	}

}