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Java-Qt-TCP數(shù)據傳輸

程序描述

使用Qt建立TCP Server，用Java建立TCP Client，Client發(fā)送本地圖片文件給Server，Server端使用Qt的QPixmap類顯示在QLabel實例的背景中。

核心代碼

Java端
Main.java

import java.io.*;
import java.net.Socket;

public class Main {

    public static void main(String[] args) {

        Socket s;
        File sendFile = new File("F:/Image/test8.png");
        long fileSize = sendFile.length();

        if(!sendFile.exists()) {
            System.out.println("Cannot find the file");
            return;
        }


        //定義文件輸入流，用于打開、讀取文件
        FileInputStream fileInputStream = null;
        try {
            fileInputStream = new FileInputStream(sendFile);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }

        //使用OutputStream向Socket發(fā)送數(shù)據
        OutputStream outputStream = null;
        //使用InputStream從Socket接收數(shù)據
        InputStream inputStream = null;

        /*建立客戶端，連接服務器*/
        try {
            s = new Socket("127.0.0.1", 8899);
            outputStream = s.getOutputStream();

            int size = 0;
            byte[] buffer = new byte[(int) fileSize];

            while((size = fileInputStream.read(buffer)) != -1) {
                System.out.println("Data size: \t" + size);
                outputStream.write(buffer, 0, size);
                outputStream.flush();
            }

            //接收服務器反饋信息,等待數(shù)據傳輸結果確認
            while(true) {
                inputStream = s.getInputStream();
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
                BufferedReader br = new BufferedReader(inputStreamReader);
                  String str = br.readLine();
                  System.out.println("Server: \t" + str);
                  /*不能使用 (str == "ok") 判斷，因為str是String類型的，
                  "ok"是字符串數(shù)組，直接用==進行比較是不相等的*/
                  if (str.equals("ok")) {
                      break;
                  }
              }
          } catch (IOException e) {
              System.out.println("Cannot connect the Server.");
              e.printStackTrace();
          }
      }
  }

Qt端
mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
// 2.添加頭文件
#include <QTcpServer>
#include <QTcpSocket>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();

// 4.添加信號槽
public slots:
    void slotNewConnection();
    void slotReceiveData();
    void slotSocketDisconnect();

private slots:
    void on_startServerBtn_clicked();

private:
    Ui::MainWindow *ui;
    // 3.添加成員 TCP Server和TCP Socket
    QTcpServer *myServer;
    QTcpSocket *mySocket;

};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QHostAddress>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    //初始化GUI組件
    ui->imgShowLabel->setScaledContents(true);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_startServerBtn_clicked()
{
    //5.按鈕事件
    ui->startServerBtn->setText("Listening...");
    ui->startServerBtn->setEnabled(false);

    this->myServer = new QTcpServer(this);
    this->myServer->listen(QHostAddress::Any, 8899);

    //連接myServer的newConnection()信號與MainWindow的槽函數(shù)slotNewConnection()
    connect(this->myServer, SIGNAL(newConnection()), this, SLOT(slotNewConnection()));

}

void MainWindow::slotNewConnection()
{
    //使用mySocket接收客戶端連接(這里只允許考慮一個連接的情況)
    this->mySocket = this->myServer->nextPendingConnection();
    //更新GUI
    ui->startServerBtn->setText("Client Connected.");

    //監(jiān)聽socket連接狀態(tài),準備接收數(shù)據
    //連接信號與槽
    connect(this->mySocket, SIGNAL(readyRead()), this, SLOT(slotReceiveData()));
    connect(this->mySocket, SIGNAL(disconnected()), this, SLOT(slotSocketDisconnect()));

    //控制臺輸出"Client connected success."
    qDebug()<<"Client connected success.";

}

void MainWindow::slotReceiveData()
{
    qDebug()<<"Start receive data from Client...";

    QByteArray bytes = NULL;
    while(this->mySocket->waitForReadyRead(100))
    {
        qDebug()<<"Data receiving...";
        bytes.append(this->mySocket->readAll());
    }

    //Send Back Data to Client
    if(this->mySocket->isWritable())
    {
        //結尾中的'\n'表示數(shù)據發(fā)送完畢
        QString sendData = "ok\n" ;
        this->mySocket->write(sendData.toStdString().c_str(), strlen(sendData.toStdString().c_str()));
    }
    else
    {
        qDebug()<<"Cannot send back data to Client.";
    }


    QPixmap pixmap;
    pixmap.loadFromData(bytes);
    //顯示到GUI中
    ui->imgShowLabel->setPixmap(pixmap);

}

void MainWindow::slotSocketDisconnect()
{
    this->mySocket->close();
    ui->startServerBtn->setText("Listening...");
    qDebug()<<"Socket disconnected";
}