智能家居状态监控：Qt C++ 客户端与 Linux C 服务器交互

以下是一个示例代码，用于实现客户端 Qt C++ 存储在 sqlite 的智能家居状态表，并通过 TCP/IP 协议从 Linux C 服务器获取最新的温度和湿度数据，并根据数据制定建议发送给客户端。

客户端代码：

#include <QtWidgets>
#include <QTcpSocket>
#include <QMessageBox>
#include <QSqlDatabase>
#include <QSqlQuery>

class Client : public QWidget
{
    Q_OBJECT

public:
    Client(QWidget *parent = nullptr)
        : QWidget(parent)
    {
        // 创建GUI界面
        QVBoxLayout *layout = new QVBoxLayout(this);
        QLabel *temperatureLabel = new QLabel('Temperature: ', this);
        QLabel *humidityLabel = new QLabel('Humidity: ', this);
        QLabel *suggestionLabel = new QLabel('Suggestion: ', this);
        layout->addWidget(temperatureLabel);
        layout->addWidget(humidityLabel);
        layout->addWidget(suggestionLabel);

        // 连接到服务器
        socket = new QTcpSocket(this);
        socket->connectToHost('127.0.0.1', 1234);
        connect(socket, &QTcpSocket::readyRead, this, &Client::readData);

        // 从数据库获取智能家居状态
        QSqlDatabase db = QSqlDatabase::addDatabase('QSQLITE');
        db.setDatabaseName('home.db');
        if (!db.open()) {
            QMessageBox::critical(this, 'Error', 'Failed to open database');
            return;
        }

        QSqlQuery query;
        if (!query.exec('SELECT * FROM home_status ORDER BY id DESC LIMIT 1')) {
            QMessageBox::critical(this, 'Error', 'Failed to query database');
            return;
        }

        if (query.next()) {
            int temperature = query.value(1).toInt();
            int humidity = query.value(2).toInt();
            temperatureLabel->setText('Temperature: ' + QString::number(temperature) + '℃');
            humidityLabel->setText('Humidity: ' + QString::number(humidity) + '%');

            // 发送请求获取建议
            socket->write('get_suggestion');
        } else {
            temperatureLabel->setText('Temperature: N/A');
            humidityLabel->setText('Humidity: N/A');
        }
    }

private slots:
    void readData()
    {
        // 读取服务器发送的建议
        QByteArray data = socket->readAll();
        QString suggestion = QString::fromUtf8(data);

        // 显示建议
        QLabel *suggestionLabel = findChild<QLabel*>('suggestionLabel');
        suggestionLabel->setText('Suggestion: ' + suggestion);
    }

private:
    QTcpSocket *socket;
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    Client client;
    client.show();

    return app.exec();
}

#include "main.moc"

Linux C服务器代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define MAX_BUFFER_SIZE 1024

void handleClient(int clientSocket)
{
    char buffer[MAX_BUFFER_SIZE];
    ssize_t bytesRead;

    // 从客户端接收请求
    bytesRead = recv(clientSocket, buffer, sizeof(buffer), 0);
    buffer[bytesRead] = '\0';

    // 查询最新的温度和湿度数据
    int temperature = 0;
    int humidity = 0;
    // 查询数据库并将结果存储在temperature和humidity变量中

    // 制定建议
    char suggestion[MAX_BUFFER_SIZE];
    if (temperature < 24) {
        sprintf(suggestion, 'Temperature is too low, suggest increasing temperature to 26℃');
    } else if (humidity < 40 || humidity > 70) {
        sprintf(suggestion, 'Humidity is too high or too low, suggest adjusting humidity');
    } else {
        sprintf(suggestion, 'No suggestion at the moment');
    }

    // 发送建议给客户端
    send(clientSocket, suggestion, strlen(suggestion), 0);

    close(clientSocket);
}

int main()
{
    int serverSocket, clientSocket;
    struct sockaddr_in serverAddress, clientAddress;
    socklen_t clientAddressLength;

    // 创建套接字
    serverSocket = socket(AF_INET, SOCK_STREAM, 0);
    if (serverSocket == -1) {
        perror('Failed to create socket');
        exit(EXIT_FAILURE);
    }

    // 设置服务器地址
    serverAddress.sin_family = AF_INET;
    serverAddress.sin_addr.s_addr = htonl(INADDR_ANY);
    serverAddress.sin_port = htons(1234);

    // 绑定套接字
    if (bind(serverSocket, (struct sockaddr *)&serverAddress, sizeof(serverAddress)) == -1) {
        perror('Failed to bind socket');
        exit(EXIT_FAILURE);
    }

    // 监听连接
    if (listen(serverSocket, 5) == -1) {
        perror('Failed to listen');
        exit(EXIT_FAILURE);
    }

    while (1) {
        // 接受客户端连接
        clientAddressLength = sizeof(clientAddress);
        clientSocket = accept(serverSocket, (struct sockaddr *)&clientAddress, &clientAddressLength);
        if (clientSocket == -1) {
            perror('Failed to accept connection');
            exit(EXIT_FAILURE);
        }

        // 处理客户端请求
        handleClient(clientSocket);
    }

    // 关闭套接字
    close(serverSocket);

    return 0;
}

请注意，这只是一个简单的示例，实际应用中可能需要进行错误处理、数据验证和安全性考虑等。另外，数据库查询和建议制定的代码需要根据实际情况进行修改。