userfiledao.java

java qq 实现点对点聊天功能 并提供服务器端聊天室元代码

package dao.impl;
import java.io.*;
import java.util.*;

import dao.UserDao;
import model.User;
public class UserFileDao implements UserDao {
	private String name;
	
	public UserFileDao(String name) {
		super();
		this.name = name;
	}

	public void saveUsers(Map m){
		ObjectOutputStream out=null;
		try {
			FileOutputStream fos=new FileOutputStream(name);
			out = new ObjectOutputStream(fos);
			
			Collection c=m.values();
			Iterator it=c.iterator();
			while(it.hasNext()){
				User ac=(User)it.next();
				out.writeObject(ac);
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		finally{
			try {
				if (out!=null) out.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	
	public Map loadUsers(){
		Map m=new HashMap();
		ObjectInputStream in=null;
		try {
			FileInputStream fis=new FileInputStream(name);
			in = new ObjectInputStream(fis);
			while(true){
				User ac=(User)in.readObject();
				m.put(new Integer(ac.getId()),ac);
			}
		} catch (IOException e) {
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		finally{
			try {
				if (in!=null) in.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return m;
	}
}