QT 簡單的網絡通信（tcp ，udp）

最近要用到Qt的Socket部分，網上關於這部分的資料都比較複雜，我在這總結一下，把Socket的主要部分提取出來，實現TCP和UDP的簡單通信。

1.UDP通信

UDP沒有特定的server端和client端，簡單來說就是向特定的ip發送報文，因此我把它分爲發送端和接收端。 注意：在.pro文件中要添加QT += network，否則無法使用Qt的網絡功能。

1.1.UDP發送端

1. #include <QtNetwork>
2. QUdpSocket *sender;
3. sender = new QUdpSocket(this);
5. QByteArray datagram = “hello world!”;
7. //UDP廣播
8. sender->writeDatagram(datagram.data(),datagram.size(),QHostAddress::Broadcast,6665);
10. //向特定IP發送
11. QHostAddress serverAddress = QHostAddress("10.21.11.66");
12. sender->writeDatagram(datagram.data(), datagram.size(),serverAddress, 6665);
14. /* writeDatagram函數原型，發送成功返回字節數，否則-1
15. qint64 writeDatagram(const char *data,qint64 size,const QHostAddress &address,quint16 port)
16. qint64 writeDatagram(const QByteArray &datagram,const QHostAddress &host,quint16 port)
17. */

1.2.UDP接收端

1. #include <QtNetwork>
2. QUdpSocket *receiver;
4. //信號槽
5. private slots:
6. void readPendingDatagrams();
8. receiver = new QUdpSocket(this);
9. receiver->bind(QHostAddress::LocalHost, 6665);
10. connect(receiver, SIGNAL(readyRead()),this, SLOT(readPendingDatagrams()));
12. void readPendingDatagrams()
13. {
14. while (receiver->hasPendingDatagrams()) {
15. QByteArray datagram;
16. datagram.resize(receiver->pendingDatagramSize());
17. receiver->readDatagram(datagram.data(), datagram.size());
18. //數據接收在datagram裏
19. /* readDatagram 函數原型
20. qint64 readDatagram(char *data,qint64 maxSize,QHostAddress *address=0,quint16 *port=0)
21. */
22. }
23. }

2.TCP通信

TCP的話要複雜點，必須先建立連接才能傳輸數據，分爲server端和client端。

2.1.TCP client端

1. #include <QtNetwork>
2. QTcpSocket *client;
4. char *data="hello qt!";
5. client = new QTcpSocket(this);
6. client->connectToHost(QHostAddress("10.21.11.66"), 6665);
7. client->write(data);

2.2.TCP server端

1. #include <QtNetwork>
2. QTcpServer *server;
3. QTcpSocket *clientConnection;
5. server = new QTcpServer();
6. server->listen(QHostAddress::Any, 6665);
7. connect(server, SIGNAL(newConnection()), this, SLOT(acceptConnection()));
9. void acceptConnection()
10. {
11. clientConnection = server->nextPendingConnection();
12. connect(clientConnection, SIGNAL(readyRead()), this, SLOT(readClient()));
13. }
15. void readClient()
16. {
17. QString str = clientConnection->readAll();
18. //或者
19. char buf[1024];
20. clientConnection->read(buf,1024);
21. }