[英]QT - JAVA socket loss data
我有一個QT / C ++服務器和一個Java客戶端。 客戶端向服務器請求文件,然后服務器將流發送到客戶端。 問題是在TCP傳輸中(也在本地主機中)我丟失了一些數據包。 有時,客戶端會收到280705字節的288890。
有服務器:
MyTcpServer::MyTcpServer(QObject *parent) :
QTcpServer(parent)
{
}
void MyTcpServer::startServer(int port)
{
if(!this->listen(QHostAddress::Any, serverPort))
{
qDebug() << "Could not start server";
}
else
{
qDebug() << "Listening to port " << serverPort << "...";
}
}
void MyTcpServer::incomingConnection(qintptr socketDescriptor)
{
SocketThread *thread = new SocketThread(socketDescriptor, this);
connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
thread->start();
}
這是SocketThread:
SocketThread::SocketThread(qintptr ID, QObject *parent) :
QThread(parent)
{
this->socketDescriptor = ID;
}
void SocketThread::run()
{
socket = new QTcpSocket();
if(!socket->setSocketDescriptor(this->socketDescriptor))
{
emit error(socket->error());
return;
}
connect(socket, SIGNAL(readyRead()), this, SLOT(readyRead()), Qt::DirectConnection);
connect(socket, SIGNAL(disconnected()), this, SLOT(disconnected()));
socket->write("Welcome to the Server\r\n"); //SEND AN HELLO MESSAGE
socket->waitForBytesWritten();
exec();
}
void SocketThread::readyRead()
{
QByteArray socketByteArray = socket->readAll();
int number = 0;
QDataStream socketDataStream(socketByteArray);
socketDataStream >> number; //RECEIVE A NUMBER (I WANT 1)
if (number == 1)
{
QFile file("C:\\temp\\test.txt");
file.open(QIODevice::ReadWrite);
socket->write(QString("%1\n").arg(file.size()).toStdString().c_str()); //SEND THE FILESIZE AS STRING
socket->waitForBytesWritten();
QByteArray buffer = file.readAll();
long byteSent = socket->write(buffer); //SEND THE FILE
socket->flush();
file.close();
}
socket->close();
}
void SocketThread::disconnected()
{
socket->deleteLater();
exit(0);
}
這是JAVA客戶端:
Socket MyClient = null;
boolean connect()
{
try
{
MyClient = new Socket(remoteIP, remotePort);
MyClient.setSoTimeout(60000);
if (MyClient != null) {
inFromServer = new BufferedReader(new InputStreamReader(MyClient.getInputStream()));
serverWelcomeMessage = inFromServer.readLine(); //RECEIVE THE WELCOME MESSAGE
}
}
catch (IOException e) {
...
}
}
void requestFile()
{
try {
FileOutputStream fos = null;
BufferedOutputStream bos = null;
DataOutputStream outToServer = new DataOutputStream(MyClient.getOutputStream());
outToServer.write(encodeIntToByteArray(1)); //SEND THE 1
outToServer.flush();
InputStream is = MyClient.getInputStream();
int remoteFileSize = Integer.parseInt(inFromServer.readLine()); //RECEIVE THE FILESIZE AS STRING
fos = new FileOutputStream(output);
bos = new BufferedOutputStream(fos);
int byteCount = 0;
int totalByteCount = 0;
byte[] bytes = new byte[1400];
while ((byteCount = is.read(bytes)) > 0) { //RECEIVE THE FILE
bos.write(bytes, 0, byteCount);
totalByteCount += byteCount;
}
System.out.println("Byte Received "+totalByteCount+" of "+remoteFileSize);
bos.close();
fos.close();
is.close();
}
catch(...) {
}}
文件test.txt是每行帶有數字的文件:
0
1
2
3
4
...much numbers...
50000
有時,客戶端會收到整個文件,有時會收到沒有第一部分的文件,如下所示:
60
1860
1861
1862
...much numbers...
50000
從60開始,跳到1860,然后結束到50000。
我嘗試將請求迭代1000次,然后代碼工作90%的時間傳輸所有數據。
有人可以幫助我理解嗎?
問題出在IO流的使用上。 如果沒有適當了解副作用,則不能使用其他實例:inFromServer&is。 您的確切問題是java.io.BufferedReader#defaultCharBufferSize。
我建議您在連接時初始化流和讀取器。 並在全班同學中隨處使用它們。
private Socket socket;
private OutputStream outputStream;
private Writer outputWriter;
private InputStream inputStream;
private Reader inputReader;
public void connect() throws IOException {
socket = new Socket(..., ...);
socket.setSoTimeout(60000);
outputStream = new BufferedOutputStream(socket.getOutputStream()); // Buffered
outputWriter = new OutputStreamWriter(outputStream); // Non-buffered - !important
inputStream = new BufferedInputStream(socket.getInputStream()); // Buffered
inputReader = new InputStreamReader(inputStream); // Non-buffered - !important
}
而且最好將Java命名約定用於Java代碼。
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