Qt开发：TCP和UDP网络通信

【原文】http://wuyuans.com/2013/03/qt-socket/

这篇文章简洁清晰

TCP

客户端

#include <QtNetwork>
QTcpSocket *client;
char *data="hello qt!";
client = new QTcpSocket(this);
client->connectToHost(QHostAddress("10.21.11.66"), 6665);
client->write(data);

服务端

#include <QtNetwork>
QTcpServer *server;
QTcpSocket *clientConnection;
server = new QTcpServer();
server->listen(QHostAddress::Any, 6665);
connect(server, SIGNAL(newConnection()), this, SLOT(acceptConnection()));
void acceptConnection()
{
    clientConnection = server->nextPendingConnection();
    connect(clientConnection, SIGNAL(readyRead()), this, SLOT(readClient()));
}
void readClient()
{
    QString str = clientConnection->readAll();
    //或者
    char buf[1024];
    clientConnection->read(buf,1024);
}

UDP

客户端

#include <QtNetwork>
QUdpSocket *sender;
sender = new QUdpSocket(this);
QByteArray datagram = “hello world!”;
//UDP广播
sender->writeDatagram(datagram.data(),datagram.size(),QHostAddress::Broadcast,6665);
//向特定IP发送
QHostAddress serverAddress = QHostAddress("10.21.11.66");
sender->writeDatagram(datagram.data(), datagram.size(),serverAddress, 6665);
/* writeDatagram函数原型，发送成功返回字节数，否则-1
qint64 writeDatagram(const char *data,qint64 size,const QHostAddress &address,quint16 port)
qint64 writeDatagram(const QByteArray &datagram,const QHostAddress &host,quint16 port)
*/

服务端

#include <QtNetwork>
QUdpSocket *receiver;
//信号槽
private slots:  
    void readPendingDatagrams(); 
receiver = new QUdpSocket(this);
receiver->bind(QHostAddress::LocalHost, 6665);
connect(receiver, SIGNAL(readyRead()),this, SLOT(readPendingDatagrams()));
void readPendingDatagrams()
 {
     while (receiver->hasPendingDatagrams()) {
         QByteArray datagram;
         datagram.resize(receiver->pendingDatagramSize());
         receiver->readDatagram(datagram.data(), datagram.size());
         //数据接收在datagram里
/* readDatagram 函数原型
qint64 readDatagram(char *data,qint64 maxSize,QHostAddress *address=0,quint16 *port=0)
*/
     }
 }

注意

• 只是简单的收发功能，其中服务器和客户端收发的API是一样的
• 可以获取所连接的IP和port，未写
• 可以绑定其他的信号槽，比如disconnect，未写
• udp发送不一定要广播，可以指定ip和端口
• 以上代码需要添加到h和cpp的合适位置