简单Qt网络通信

最近要用到Qt的Socket部分，网上关于这部分的资料都比较复杂，我在这总结一下，把Socket的主要部分提取出来，实现TCP和UDP的简单通信。

1.UDP通信

UDP没有特定的server端和client端，简单来说就是向特定的ip发送报文，因此我把它分为发送端和接收端。 注意：在.pro文件中要添加QT += network，否则无法使用Qt的网络功能。

1.1.UDP发送端

 #include <QtNetwork>
 QUdpSocket *sender;
 sender = new QUdpSocket(this);
 QByteArray datagram = “hello world!”;
 //UDP广播
 sender->writeDatagram(datagram.data(),datagram.size(),QHostAddress::Broadcast,);
 //向特定IP发送
 QHostAddress serverAddress = QHostAddress("10.21.11.66");
 sender->writeDatagram(datagram.data(), datagram.size(),serverAddress, );
 /* 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)
 */

1.2.UDP接收端

 #include <QtNetwork>
 QUdpSocket *receiver;
 //信号槽
 private slots:
 void readPendingDatagrams();
 receiver = new QUdpSocket(this);
 receiver->bind(QHostAddress::LocalHost, );
 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)
 */
 }
 }

2.TCP通信

TCP的话要复杂点，必须先建立连接才能传输数据，分为server端和client端。

2.1.TCP client端

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

2.2.TCP server端

 #include <QtNetwork>
 QTcpServer *server;
 QTcpSocket *clientConnection;
 server = new QTcpServer();
 server->listen(QHostAddress::Any, );
 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[];
 clientConnection->read(buf,);
 }