用软件Qt编写一个局域网聊天程序；要求多个client能够聊天（接收、发送消息）。 系统分为服务器和客户端。 服务器主要是保存在线client的信息（name，ip，port）； Client端是用户端,能够与其他client进行聊天； Client启动时将信息（name，ip，port）传输到服务器端。 Client要查看在线：list命令 Client要聊天：talkto 命令，分别写出.cpp和.h和.pro的代码

.cpp代码：

Client.cpp

#include "Client.h"
#include <QDataStream>
#include <QHostAddress>

Client::Client(QObject *parent)
    : QTcpSocket(parent)
{
    connect(this, &Client::readyRead, this, &Client::processReadyRead);
    connect(this, &Client::disconnected, this, &Client::destroyed);
}

QString Client::name() const
{
    return m_name;
}

void Client::setName(const QString &name)
{
    m_name = name;
}

void Client::processReadyRead()
{
    QDataStream in(this);
    in.setVersion(QDataStream::Qt_5_9);

    while (bytesAvailable() > 0) {
        if (m_blockSize == 0) {
            if (bytesAvailable() < static_cast<qint64>(sizeof(quint16)))
                return;

            in >> m_blockSize;
        }

        if (bytesAvailable() < m_blockSize)
            return;

        QString message;
        in >> message;

        emit messageReceived(this, message);

        m_blockSize = 0;
    }
}

void Client::sendMessage(const QString &message)
{
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out.setVersion(QDataStream::Qt_5_9);

    out << quint16(0) << message;

    out.device()->seek(0);
    out << quint16(block.size() - sizeof(quint16));

    write(block);
}

Server.cpp

#include "Server.h"
#include "Client.h"
#include <QTcpServer>
#include <QDataStream>
#include <QHostAddress>

Server::Server(QObject *parent)
    : QObject(parent)
    , m_server(new QTcpServer(this))
{
    connect(m_server, &QTcpServer::newConnection, this, &Server::processNewConnection);

    if (!m_server->listen(QHostAddress::Any, 1234))
        qFatal("Failed to listen on port 1234.");
}

void Server::processNewConnection()
{
    while (m_server->hasPendingConnections()) {
        auto socket = m_server->nextPendingConnection();

        auto client = new Client(this);
        client->setSocketDescriptor(socket->socketDescriptor());

        connect(client, &Client::messageReceived, this, &Server::processMessageReceived);
        connect(client, &Client::destroyed, this, &Server::processClientDisconnected);

        m_clients.append(client);

        qDebug() << "Client connected from " << client->peerAddress().toString();

        sendClientList();
    }
}

void Server::processMessageReceived(Client *client, const QString &message)
{
    if (message.startsWith(QLatin1String("name:"))) {
        client->setName(message.mid(5));

        qDebug() << "Client " << client->name() << " set name.";
        sendClientList();
    } else if (message == QLatin1String("list")) {
        sendClientList(client);
    } else if (message.startsWith(QLatin1String("talkto:"))) {
        QStringList parts = message.split(':');
        QString targetName = parts[1];
        QString text = parts[2];

        for (auto c : m_clients) {
            if (c->name() == targetName) {
                c->sendMessage(QString("%1: %2").arg(client->name(), text));
                return;
            }
        }

        client->sendMessage(QString("Client %1 not found or not online.").arg(targetName));
    } else {
        qDebug() << "Message from " << client->name() << ": " << message;
    }
}

void Server::processClientDisconnected(QObject *obj)
{
    auto client = static_cast<Client*>(obj);

    qDebug() << "Client disconnected: " << client->name();

    m_clients.removeAll(client);

    sendClientList();
}

void Server::sendClientList(Client *client)
{
    QString list;
    for (auto c : m_clients) {
        if (c != client) {
            if (!list.isEmpty())
                list += QLatin1Char('\n');

            list += c->name();
        }
    }

    if (client)
        client->sendMessage(QString("Online clients:\n%1").arg(list));
    else
        broadcastMessage(QString("Online clients:\n%1").arg(list));
}

void Server::broadcastMessage(const QString &message)
{
    for (auto c : m_clients)
        c->sendMessage(message);
}

.h代码：

Client.h

#ifndef CLIENT_H
#define CLIENT_H

#include <QTcpSocket>

class Client : public QTcpSocket
{
    Q_OBJECT

public:
    explicit Client(QObject *parent = nullptr);

    QString name() const;
    void setName(const QString &name);

    void sendMessage(const QString &message);

signals:
    void messageReceived(Client *client, const QString &message);

private slots:
    void processReadyRead();

private:
    QString m_name;
    quint16 m_blockSize = 0;
};

#endif // CLIENT_H

Server.h

#ifndef SERVER_H
#define SERVER_H

#include <QObject>
#include <QList>

class QTcpServer;
class Client;

class Server : public QObject
{
    Q_OBJECT

public:
    explicit Server(QObject *parent = nullptr);

private slots:
    void processNewConnection();
    void processMessageReceived(Client *client, const QString &message);
    void processClientDisconnected(QObject *obj);

private:
    void sendClientList(Client *client = nullptr);
    void broadcastMessage(const QString &message);

    QTcpServer *m_server = nullptr;
    QList<Client*> m_clients;
};

#endif // SERVER_H

.pro代码：

QT += network
CONFIG += c++11
TEMPLATE = app
TARGET = ChatServer

HEADERS += \
    Client.h \
    Server.h

SOURCES += \
    main.cpp \
    Client.cpp \
    Server.cpp