与我的聊天RMI程序共享文件

Question

我一直在学校做一个RMI聊天系统，想要与它共享某种文件。之前没有做过这样的事情而且在学校没有这样做，但我想尝试一下。在谷歌和这个做了一些搜索 http://java.sun.com/developer/technicalArticles/RMI/rmi_corba/ 是我找到的最好的。这个“技术”是新的，所以我可以使用它吗？没有让它工作，但这可能是我缺乏Java知识。 一些提示为什么我不能让它工作？

Answer 1

来回发送邮件和发送文件之间没有太大的区别。答案很大程度上取决于您当前的代码是什么样的。你有一些代码要分享吗？

您当前的RMI界面是什么样的？你的架构是什么样的？

您是否有客户端连接的服务器？

你有方法sendChat（String message）？

关于sendChat（），你可以添加一个sendFile（...）。那么问题就是你想为参数做些什么。

您要发送java.io.File对象吗？一个byte []（以及一个String名称，可能是一个区分二进制文件的布尔标志）？

看到这是你第一次这样做，你可能想要自己编写世俗的部分。但是，从文件中获取字节等任务是相当常见的烦恼。 Apache commons和Google guava库都提供了简化流程的方法。我想这取决于你对这个项目的学习目标。

Answer 2

是。客户端连接到服务器，并能够在聊天室中聊天。

以下是我们迄今为止的一些代码，除了用于连接和与数据库通信的文件以及GUI之外。谢谢你回答。

• 的接口：

Chatfront界面：

public interface ChatFront extends Remote {
            boolean registerClient(Client client, String password) throws RemoteException;
            void logMeOut(Client client) throws RemoteException;
            void newChannelMessage(String toChannel, String fromUser, String message) throws RemoteException;
            void newPrivateMessage(String fromUser, String toUser, String message) throws RemoteException;
            String connectChannel(String username, String channel) throws RemoteException;
            String disconnectChannel(String username, String channel) throws RemoteException;
            boolean isUserRegistered(String username) throws RemoteException;
            void errorMessage(String toUser, String message) throws RemoteException;
    }

客户端界面：

public interface Client extends Remote {
        String findName() throws RemoteException;
    void newPrivateMessage(String fromUser, String toUser, String message) throws RemoteException;
        void newMessageChannel(String toChannel, String fromUser, String message) throws RemoteException;
        void newSystemMessageChannel(String toChannel, String fromUser, String message) throws RemoteException;
        void errorMessage(String toUser, String message) throws RemoteException;
} 

<强>了Serverside：

class ChatServer {
  public static void main(String[] args) throws Exception {
    String objectname = "chatter";
    LocateRegistry.createRegistry(1099);
    ChatFront cf = new ChatFrontImpl();
    Naming.rebind(objectname, cf);
    javax.swing.JOptionPane.showMessageDialog(null, "Tjener kjører. Trykk OK for å avslutte tjeneren.");
    Naming.unbind(objectname);
    System.exit(0);
  } 
}

ChatFrontImpl.java

package server;

import Interfaces.ChatFront;
import Interfaces.Client;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 *
 * @author sindre
 */
class ChatFrontImpl extends UnicastRemoteObject implements ChatFront {

    private UserDAC u = new UserDAC();
    private Hashtable<String, ArrayList<String>> channels = new Hashtable<String, ArrayList<String>>();
    private ArrayList<Client> clients = new ArrayList<Client>();

    public ChatFrontImpl() throws RemoteException {
    }

    /* Registrerer en ny client */
    @Override
    public synchronized boolean registerClient(Client client, String password) throws RemoteException {
        if(!u.logIn(client.findName(), password)){
            System.out.println("feil username eller password");
            return false;
        }
    if (!clients.contains(client)) {
            try {
                clients.add(client);
          System.out.println("Na er " + client.findName() + " registrert.");    
      } catch (Exception e){
          System.out.println("Feil oppstatt i registrerMeg(): " + e);
          }
              return true;
         } else
            return false;
    }  

    /* Kobler en client til en kanal */
    @Override
    public String connectChannel(String username, String kanal) throws RemoteException{ 
        if(isUserRegistered(username)){
           if (!channels.containsKey(kanal)) {
            String message = "Bruker " + username + " har ankommet kanalen";
            channels.put(kanal, new ArrayList<String>());
            channels.get(kanal).add(username);
            notifyChannelSystem(kanal, "SYSTEM", message);
            notifySelf(username, "Skriv /? for mulige kommandoer");
            return("Kanal opprettet, og bruker satt i kanalen.");
        }
        else{
            if(channels.get(kanal).contains(username)){
                return ("Brukeren er allerede i kanalen.");
            } else {
                channels.get(kanal).add(username);
                    String message = "Bruker " + username + " har ankommet kanalen";
                    notifyChannelSystem(kanal, "SYSTEM", message);
                return ("Kanal fantes allerede. Bruker satt i kanalen.");
              }
        }
        }
        return "";
    }

    /*Sjekker om brukeren ikke er blank.*/
    @Override
    public boolean isUserRegistered(String username){
        if(username.equals("")){
            return false;
        }
        return true;
    }

    /* Kobler en bruker fra en kanal */
    @Override
    public String disconnectChannel(String username, String channel) throws RemoteException{
        if(isUserInChannelX(username, channel)){
            channels.get(channel).remove(username);
            String message = "Bruker " + username + " har forlatt kanalen.";
            notifySelf(username, " Du har nå forlatt kanalen " + channel);
            notifyChannelSystem(channel, "SYSTEM", message);
            if(channels.get(channel).isEmpty()){
                channels.remove(channel);
            } 
        }
        return ("Bruker har forlatt kanalen.");
    }

    /* Kobler en client fra clientlisten */
    @Override
    public synchronized void logMeOut(Client client) throws RemoteException {
        boolean isfound = false;
        int clientIndeks = 0;
        while (clientIndeks < clients.size() && !isfound) {
            Client denne = clients.get(clientIndeks);
            if (denne.equals(client)) {  // bruker equals() for a sammenlikne stubbobjektene
                isfound = true;
                clients.remove(clientIndeks);
                System.out.println("Na er clienten " + client.findName() + " fjernet.");
            } else clientIndeks++;
        }
      }

    /* Sjekker om brukeren finnes i en gitt kanal */
    public boolean isUserInChannelX(String bruker, String kanal){
        if(channels.containsKey(kanal) && channels.get(kanal).contains(bruker)){
            return true;
        } else {
            return false;
        }   
    }

    /* Kaller metoden varsleKanal()*/
    @Override
    public void newChannelMessage(String tilKanal, String fraBruker, String message) throws RemoteException{
        if(isUserInChannelX(fraBruker, tilKanal)){
            notifyChannel(tilKanal, fraBruker, message);
        }
        else{
        }
    }

    /* Kaller metoden varsleEn() */
    @Override
    public void newPrivateMessage(String fra, String toUser, String message) throws RemoteException{
            notifyUser(fra,toUser,message);
    }

    @Override
    public void errorMessage(String toUser, String message) throws RemoteException{
        notifySelf(toUser, message);
    }

    private void notifySelf(String toUser, String message) throws RemoteException{
        for(Client k: clients){
            if(k.findName().equals(toUser)){
                k.errorMessage(toUser, message);
            }
        }
    }

    /* Bruker metoden nymessagePrivat() + ser om brukeren er tilkoblet*/
    private void notifyUser(String fromUser, String toUser, String message) throws RemoteException{
        boolean funnet = false;
        for(Client k : clients){
            if(k.findName().equals(toUser)){
                k.newPrivateMessage(fromUser, toUser, message);
                  funnet = true;
            }
        }
        if (!funnet) errorMessage(fromUser, "Ingen brukere ved dette navnet!");
    }

    /* Kjører metoden nymessageKanal() */
    private void notifyChannel(String toChannel, String fromUser, String message) throws RemoteException{
            if(channels.containsKey(toChannel) && isUserRegistered(fromUser)){
                for(String k : channels.get(toChannel)){
                    for(Client cli : clients){
                        if(cli.findName().equals(k)){
                            cli.newMessageChannel(toChannel, fromUser, message);
                        }
                    }
                }
            }
            else{
                System.out.println("Brukeren er ikke registrert.");
            }
        }

    private void notifyChannelSystem(String toChannel, String fromUser, String message) throws RemoteException{
        if(channels.containsKey(toChannel) && isUserRegistered(fromUser)){
                for(String k : channels.get(toChannel)){
                    for(Client kli : clients){
                        if(kli.findName().equals(k)){
                            kli.newMessageChannel(toChannel, fromUser, message);
                        }
                    }
                }
            }
            else{
                System.out.println("Brukeren er ikke registrert.");
            }
    }
}

<强>客户机侧：

GUILogic.java

package gui;

import Interfaces.ChatFront;
import Interfaces.Client;
import java.rmi.Naming;
import java.rmi.RemoteException;
import klient.ClientImpl;

/**
 *
 * @author sindre
 */
public class GUILogic {
    GUI gui;
    ChatFront cf;
    public String username;
    public String channel;
    public String password;
    public String message;

    public GUILogic(GUI gui){
        this.gui = gui;  
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getChannel() {
        return channel;
    }

    public void setChannel(String channel) {
        this.channel = channel;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    /* Kobler GUI klienten opp mot serveren */
    public void createCFConnection(String username, String password) throws Exception{

        String objectname = "chatter";
        String hostname = "localhost";
        String url = "rmi://" + hostname + "/" + objectname;

        cf = (ChatFront) Naming.lookup(url);

        Client k = new ClientImpl(username, gui);
        cf.registerClient(k, password);
    }

    public void connectChannel(String username, String channel) throws RemoteException{
        cf.connectChannel(username, channel);
    }

    public void disconnectChannel(String username, String channel) throws RemoteException{
        cf.disconnectChannel(username, channel);
    }

    public void newChannelMessage(String toChannel, String fromUser, String message) throws RemoteException{
        cf.newChannelMessage(fromUser ,toChannel, message);
    }

    public void newPrivateMessage(String fromUser, String toUser, String message) throws RemoteException{
        cf.newPrivateMessage(fromUser, toUser, message);
    }

    public void errorMessage(String toUser, String message) throws RemoteException{
        cf.errorMessage(toUser, message);
    }

    /* Logger klienten av GUIen */
    public boolean logOut(String username) throws RemoteException{
        Client k = new ClientImpl(username, gui);
        if(k.findName().equals("")){
            return false;      
        } else {
            cf.logMeOut(k);
            System.out.println("user " + username + " logget ut.");
            return true;
        }
    }

    /* Analysermessage har funnet / i starten av messageen, og da blir denne metoden kjørt. */
   public String commandWritten(String username, String channel, String message) throws RemoteException{
        String[] result = message.split(" ", 3);
        String channel1;

        if((result[0].equalsIgnoreCase("/join") || (result[0].equalsIgnoreCase("/j")))){
            channel1 = result[1];
            setChannel(channel1);
            connectChannel(username, channel1);
        }

        else if(result[0].equalsIgnoreCase("/leave") || (result[0].equalsIgnoreCase(("/l")))){
            channel = result[1];
            disconnectChannel(username, channel);
        }

        else if(result[0].equalsIgnoreCase("/whisper") || (result[0].equalsIgnoreCase(("/w")))){
            for (int x=2; x<result.length; x++)
            newPrivateMessage(username, result[1], result[x]);
        }

        else if(result[0].equalsIgnoreCase("/exit") || (result[0].equalsIgnoreCase(("/e")))){
            System.exit(0);
        }

        else if(result[0].equalsIgnoreCase("/?")){
            errorMessage(username, "Mulige kommandoer er:" + "\n" + 
                    "/leave 'channel' eller /l" + "\n" +
                    "/whisper 'username' eller /w" + "\n" +
                    "/join 'channel' eller /j" + "\n" +
                    "/exit eller /e" + "\n");
        } 
        else{  
           errorMessage(username, "Feil kommando! Skriv /? for mulige kommandoer");
        } 
        return message;
    }

    /* Analyserer messageen som skrives inn i messagefeltet. Kommandoer starter med / */
    public void analyzeMessage(String username, String channel, String message) throws RemoteException{
        String text = getMessage().toLowerCase();
        char command = '/';
        for(int i = 0; i<1; i++){
            char c = text.charAt(0);
            if(c == command){
                commandWritten(username, channel, text);
            }
            else {
                newChannelMessage(username, channel, text); 
            }
        }           
    }
}