C++ SQLite3 智能家居设备状态监测系统服务器端代码解析

#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('%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'); // 发送userid给服务器 int userid = this->userid; if (m_socket->write(reinterpret_cast<const char*>(&userid), sizeof(int)) == -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()));

}

userid传的是123，但服务器显示的是2063597568 正在连接中... 客户端已连接 2063597568列数：6 接收设备状态信息失败: No such file or directory内容：根据代码分析，问题可能出现在客户端发送userid的部分。在客户端的代码中，使用了QByteArray和QDataStream来发送userid，但是在服务器端的代码中，使用了recv函数来接收userid。这两种方式不兼容，导致服务器接收到的数据不正确。

解决方法是在客户端代码中使用与服务器端相同的方式来发送userid，即使用send函数。

修改客户端代码如下：

void Procession::connected()
{
    ui->message->append('连接成功');
    // 发送userid给服务器
    int userid = this->userid;
    if (m_socket->write(reinterpret_cast<const char*>(&userid), sizeof(int)) == -1) {
        ui->message->append('发送userid失败');
        m_socket->close();
    }
}

修改完客户端代码后重新编译运行，应该可以正确发送userid给服务器。