• 日期: 2026-06-07
  • 标签: 常规

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <sys/select.h> #include <arpa/inet.h> #include <sqlite3.h>

#define MAX_BUFFER_SIZE 1024

typedef struct { int uid; char device_name[10]; char device_state[10]; char value[10]; char mode[10]; } Status;

typedef struct { int sockfd; struct sockaddr_in client_addr; socklen_t client_addr_len; sqlite3 *db; } ServerContext;

void handleClientRequest(ServerContext *context) { char buffer[MAX_BUFFER_SIZE]; int userid;

// 接收客户端发送的userid
ssize_t recvSize = recv(context->sockfd, &userid, sizeof(int), 0);
if (recvSize == -1) {
    perror("userid接受失败\nrecv");
    return;
}
printf("客户端已连接\n");
printf("userid:%d",userid);
// 查询数据库获取设备状态信息
char sql[100];
snprintf(sql, sizeof(sql), "SELECT * FROM Status WHERE uid = %d", userid);
sqlite3_stmt *stmt;
int rc = sqlite3_prepare_v2(context->db, sql, -1, &stmt, NULL);
if (rc != SQLITE_OK) {
    fprintf(stderr, "无法执行的语句: %s\n", sqlite3_errmsg(context->db));
    return;
}

Status status;
memset(&status, 0, sizeof(Status)); // 清空status结构体
while (sqlite3_step(stmt) == SQLITE_ROW) {
    status.uid = sqlite3_column_int(stmt, 1);
    printf("%d",status.uid);
    strncpy(status.device_name, sqlite3_column_text(stmt, 2), sizeof(status.device_name));
    printf("%s",status.device_name);
    strncpy(status.device_state, sqlite3_column_text(stmt, 3), sizeof(status.device_state));
    strncpy(status.value, sqlite3_column_text(stmt, 4), sizeof(status.value));
    strncpy(status.mode, sqlite3_column_text(stmt, 5), sizeof(status.mode));
}
int columnCount = sqlite3_column_count(stmt);
  printf("列数：%d\n", columnCount);
if (sqlite3_column_count(stmt) == 0) {
      fprintf(stderr, "查询结果为空\n");
      return;
  }
sqlite3_finalize(stmt);

if (strlen(status.device_name) == 0) {
    perror("接收设备状态信息失败");
    return;
}

// 分析设备状态并生成建议
char suggestion[MAX_BUFFER_SIZE];
if (strcmp(status.device_name, "空调") == 0) {
    int temperature = atoi(status.value);
    if (temperature < 24) {
        snprintf(suggestion, sizeof(suggestion), "空调温度过低，建议提高温度至26℃");
    } else {
        snprintf(suggestion, sizeof(suggestion), "空调温度正常");
    }
} else if (strcmp(status.device_name, "加湿器") == 0) {
    int humidity = atoi(status.value);
    if (humidity < 40 || humidity > 70) {
        snprintf(suggestion, sizeof(suggestion), "加湿器湿度过高或过低，建议调整加湿器湿度");
    } else {
        snprintf(suggestion, sizeof(suggestion), "加湿器湿度正常");
    }
} else {
    snprintf(suggestion, sizeof(suggestion), "设备状态未知");
}

// 向客户端发送建议
ssize_t sendSize = send(context->sockfd, suggestion, strlen(suggestion), 0);
if (sendSize == -1) {
    perror("发送失败\nsend");
    return;
}
printf("%s",suggestion);

}

int main() { printf("正在连接中...\n"); int sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd == -1) { perror("连接失败\nsocket"); return 1; }

struct sockaddr_in server_addr;
server_addr.sin_family = AF_INET;
server_addr.sin_addr.s_addr = INADDR_ANY;
server_addr.sin_port = htons(12345);

if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
    perror("连接失败\nbind");
    close(sockfd);
    return 1;
}

if (listen(sockfd, 5) == -1) {
    perror("连接失败\nlisten");
    close(sockfd);
    return 1;
}

sqlite3 *db;
int rc = sqlite3_open("/mnt/g/Qt/Client/Smarthome_Client/database/database.db", &db);
if (rc != SQLITE_OK) {
    fprintf(stderr, "数据库打开失败: %s\n", sqlite3_errmsg(db));
    return 1;
}

ServerContext context;
context.sockfd = sockfd;
context.client_addr_len = sizeof(context.client_addr);
context.db = db;

fd_set readfds;
int maxfd = sockfd;

while (1) {
    FD_ZERO(&readfds);
    FD_SET(sockfd, &readfds);

    int activity = select(maxfd + 1, &readfds, NULL, NULL, NULL);
    if (activity == -1) {
        perror("select");
        break;
    }

    if (FD_ISSET(sockfd, &readfds)) {
        int clientSockfd = accept(sockfd, (struct sockaddr *)&context.client_addr, &context.client_addr_len);
        if (clientSockfd == -1) {
            perror("套接字接收失败\naccept");
            break;
        }

        context.sockfd = clientSockfd;
        handleClientRequest(&context);

        close(clientSockfd);
    }
}
sqlite3_close(db);
close(sockfd);
printf("服务器已关闭\n");

return 0;

}

下面是客户端的代码 #include "procession.h" #include "ui_procession.h" #include #include

Procession::Procession(int userid,QWidget *parent) : QWidget(parent), ui(new Ui::Procession), userid(userid) { ui->setupUi(this); processionWidget(); m_socket = new QTcpSocket(this); //connect(ui->connectBtn, &QPushButton::clicked, this, &Procession::on_connectBtn_clicked); connect(m_socket, &QTcpSocket::readyRead, this, &Procession::readyRead); connect(m_socket, &QTcpSocket::connected, this, &Procession::connected); connect(m_socket, &QTcpSocket::disconnected,this,&Procession::disconnected); connect(m_socket, QOverloadQAbstractSocket::SocketError::of(&QTcpSocket::error), this, &Procession::displayError); }

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

void Procession::processionWidget() { setWindowTitle("服务器通信"); setAutoFillBackground(true); QPalette palette=this->palette(); QPixmap pixmap(":/user/image/image/net.jpg"); palette.setBrush(QPalette::Window, QBrush(pixmap)); setPalette(palette); setFixedSize(600,400); }

void Procession::connected() { ui->message->append("连接成功"); QByteArray block; QDataStream out(&block, QIODevice::WriteOnly); out << static_cast(this->userid); if (m_socket->write(block) == -1) { ui->message->append("发送userid失败"); m_socket->close(); } }

void Procession::disconnected() { ui->message->append("连接失败"); m_socket->close(); }

void Procession::readyRead() { QByteArray data = m_socket->readAll(); if (data.isEmpty()) { ui->message->append("读取的数据为空"); return; } // 解析服务器返回的数据 QDataStream in(&data, QIODevice::ReadOnly); QString suggestion; in >> suggestion; // 使用重载的 >> 运算符来读取数据 if (in.status() != QDataStream::Ok) { ui->message->append("解析服务器返回的数据失败"); return; } ui->message->append(suggestion); m_socket->close(); }

void Procession::displayError(QAbstractSocket::SocketError error) { QString errorMessage; switch (error) { case QAbstractSocket::ConnectionRefusedError: errorMessage = "连接被拒绝"; break; case QAbstractSocket::RemoteHostClosedError: errorMessage = "远程主机关闭"; break; case QAbstractSocket::HostNotFoundError: errorMessage = "未找到主机"; break; case QAbstractSocket::SocketTimeoutError: errorMessage = "连接超时"; break; case QAbstractSocket::NetworkError: errorMessage = "网络错误"; break; default: errorMessage = "未知错误"; break; } ui->message->append("连接失败：" + errorMessage); }

void Procession::on_connectBtn_clicked() { if (m_socket->state() == QAbstractSocket::ConnectedState) { m_socket->disconnectFromHost(); // 先关闭套接字 qDebug() << "1"; }

ui->message->append("已经连接上服务器");
QString ip = ui->IP->text();
QString port = ui->port->text();

if (ip.isEmpty() || port.isEmpty()) {
    ui->message->clear();
    ui->message->append("请输入有效的IP地址和端口号");
    return;
}

ui->message->clear();
ui->message->append("正在连接中...");
m_socket->connectToHost(ip, static_cast<quint16>(ui->port->text().toInt()));

}

#ifndef PROCESSION_H #define PROCESSION_H

#include #include #include #include #include

namespace Ui { class Procession; }

class Procession : public QWidget { Q_OBJECT

public: explicit Procession(int userid,QWidget *parent = nullptr); ~Procession(); void processionWidget();

private slots: //void on_pushButton_clicked(); void connected(); void disconnected(); void readyRead(); void displayError(QAbstractSocket::SocketError error);

void on_connectBtn_clicked();

private: Ui::Procession ui; int userid; QTcpSocket m_socket; };

#endif // PROCESSION_H

客户端传的userid是123，但服务器接收到的是2063597568 服务器运行结果 正在连接中... 客户端已连接 userid:2063597568列数：6 接收设备状态信息失败: No such file or directory

服务器是c文件，客户端是cpp文件，不能使用QDataStream内容：问题出在客户端发送userid的代码上。

在客户端的connected()函数中，应该先创建一个QDataStream对象，然后再将userid写入该对象，最后再通过socket发送该对象的数据。

修改connected()函数如下：

void Procession::connected()
{
    ui->message->append("连接成功");
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
    out << static_cast<qint32>(this->userid); // 使用qint32类型
    if (m_socket->write(block) == -1) {
        ui->message->append("发送userid失败");
        m_socket->close();
    }
}

然后在服务器端的handleClientRequest()函数中，接收userid时使用qint32类型接收，并打印出来。

修改handleClientRequest()函数如下：

void handleClientRequest(ServerContext *context) {
    qint32 userid; // 使用qint32类型
    ssize_t recvSize = recv(context->sockfd, &userid, sizeof(qint32), 0); // 使用sizeof(qint32)
    if (recvSize == -1) {
        perror("userid接受失败\nrecv");
        return;
    }
    printf("客户端已连接\n");
    printf("userid:%d\n", userid); // 打印userid
    // ...
}

这样就可以正确地传递和接收userid了。

C语言实现智能家居设备状态监控服务器

原文地址: http://www.cveoy.top/t/topic/fCuM 著作权归作者所有。请勿转载和采集!

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