• 日期: 2024-06-08 18:10:41
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智能家居系统数据库设计与C++/Qt网络通信实现

本文将介绍如何使用SQLite数据库和C++/Qt构建一个简单的智能家居系统，涵盖以下内容：

  1. 数据库设计：创建用户表和设备状态表。2. 服务器端实现：使用C++和SQLite实现一个简单的服务器，用于存储和检索设备状态信息。3. 客户端实现：使用Qt实现一个简单的客户端，用于连接服务器、发送用户ID并接收服务器返回的建议。

1. 数据库设计

我们使用SQLite数据库来存储用户信息和设备状态信息。以下是数据库表的创建语句：sql-- 创建用户表CREATE TABLE IF NOT EXISTS users ( uid INTEGER PRIMARY KEY AUTOINCREMENT, username varchar(10), passwd varchar(10));

-- 创建智能家居状态表CREATE TABLE IF NOT EXISTS Status ( sid INTEGER PRIMARY KEY AUTOINCREMENT, uid INTEGER, device_name varchar(10), device_state varchar(10), value varchar(10), mode varchar(10), FOREIGN KEY (uid) REFERENCES users (uid));

2. 服务器端实现 (C++)c++#include <stdio.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <sys/socket.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

recv'); return; } printf('客户端已连接 ');

// 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

', sqlite3_errmsg(context->db)); return; }

Status status;    while (sqlite3_step(stmt) == SQLITE_ROW) {        status.uid = sqlite3_column_int(stmt, 1);        strncpy(status.device_name, sqlite3_column_text(stmt, 2), sizeof(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));    }    sqlite3_finalize(stmt);

// 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

send'); return; }}

void handleClientConnection(ServerContext *context) { int clientSockfd = accept(context->sockfd, (struct sockaddr *)&context->client_addr, &context->client_addr_len); if (clientSockfd == -1) { perror('套接字接收失败 accept'); return; }

ServerContext clientContext;    clientContext.sockfd = clientSockfd;    clientContext.client_addr_len = sizeof(clientContext.client_addr);    clientContext.db = context->db;    handleClientRequest(&clientContext);

close(clientSockfd);}

int main() { printf('正在连接中... '); int sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd == -1) { perror('连接失败 socket'); 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

bind'); close(sockfd); return 1; }

if (listen(sockfd, 5) == -1) {        perror('连接失败

listen'); 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

', sqlite3_errmsg(db)); return 1; }

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

while (1) {        sleep(1);        handleClientConnection(&context);    }

sqlite3_close(db);    close(sockfd);    printf('服务器已关闭

');

return 0;}

3. 客户端实现 (Qt)cpp#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 QByteArray block; QDataStream out(&block, QIODevice::WriteOnly); out << 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 return; } 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()));}

客户端错误信息分析

客户端显示"连接失败：远程主机关闭"，说明客户端无法连接到服务器。这可能是由于以下几个原因导致的：

  1. 服务器未启动或未正确监听指定的端口：请确保服务器已经启动，并且监听了正确的端口。2. 服务器所在的IP地址不正确：请确保在客户端中输入了正确的服务器IP地址。3. 防火墙或网络设置导致连接失败：请检查防火墙设置和网络设置，确保允许客户端与服务器之间的通信。4. 客户端和服务器之间的网络连接不稳定：请确保客户端和服务器之间的网络连接稳定，并且没有网络故障。

请逐一排查以上可能的原因，并根据具体情况进行调整和修复。

智能家居系统数据库设计与C++/Qt网络通信实现

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

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