• 日期: 2027-07-05
  • 标签: 常规
<p>#include &lt;stdio.h&gt;
#include &lt;stdlib.h&gt;
#include &lt;string.h&gt;
#include &lt;unistd.h&gt;
#include &lt;sys/socket.h&gt;
#include &lt;sys/select.h&gt;
#include &lt;arpa/inet.h&gt;
#include &lt;sqlite3.h&gt;
#include &lt;netinet/in.h&gt;</p>
<p>#define MAX_BUFFER_SIZE 1024</p>
<p>typedef struct {
int uid;
char device_name[20];
char device_state[20];
char value[20];
char mode[20];
} Status;</p>
<p>typedef struct {
int sockfd;
struct sockaddr_in client_addr;
socklen_t client_addr_len;
sqlite3 *db;
} ServerContext;</p>
<p>void handleClientRequest(ServerContext *context) {
char buffer[MAX_BUFFER_SIZE];
int userid;</p>
<pre><code>// 接收客户端发送的userid
ssize_t recvSize = recv(context-&gt;sockfd, &amp;userid, sizeof(int), 0);

if (recvSize == -1) {
    perror('userid接受失败\nrecv');
    return;
} else if (recvSize == 0) {
    perror('客户端已关闭连接');
    return;
} else if (recvSize != sizeof(int)) {
    perror('接收到的字节数不正确');
    return;
}
userid = ntohl(userid); // 将网络字节序转换为主机字节序
printf('客户端已连接\n');
printf('userid:%d\n', 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 = NULL;
int rc = sqlite3_prepare_v2(context-&gt;db, sql, -1, &amp;stmt, NULL);
if (rc != SQLITE_OK) {
    fprintf(stderr, '无法执行的语句: %s\n', sqlite3_errmsg(context-&gt;db));
    return;
}

Status status;
memset(&amp;status, 0, sizeof(Status)); // 清空status结构体
while (sqlite3_step(stmt) == SQLITE_ROW) {
    status.uid = sqlite3_column_int(stmt, 1);

    const unsigned char *device_name = sqlite3_column_text(stmt, 2);
    if (device_name != NULL) {
        strncpy(status.device_name, device_name, sizeof(status.device_name)-1);
        status.device_name[sizeof(status.device_name)-1] = '\0';
    }

    const unsigned char *device_state = sqlite3_column_text(stmt, 3);
    if (device_state != NULL) {
        strncpy(status.device_state, device_state, sizeof(status.device_state)-1);
        status.device_state[sizeof(status.device_state)-1] = '\0';
    }

    const unsigned char *value = sqlite3_column_text(stmt, 4);
    if (value != NULL) {
        strncpy(status.value, value, sizeof(status.value)-1);
        status.value[sizeof(status.value)-1] = '\0';
    }

    const unsigned char *mode = sqlite3_column_text(stmt, 5);
    if (mode != NULL) {
        strncpy(status.mode, mode, sizeof(status.mode)-1);
        status.mode[sizeof(status.mode)-1] = '\0';
    }
}
sqlite3_finalize(stmt); // 释放查询结果集

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 &lt; 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 &lt; 40 || humidity &gt; 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-&gt;sockfd, suggestion, strlen(suggestion), 0);
if (sendSize == -1) {
    perror('发送失败\nsend');
    return;
}
else{
printf('发送成功!');
}
printf('%s\n', suggestion);
</code></pre>
<p>}</p>
<p>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;
}</p>
<pre><code>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 *)&amp;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', &amp;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(&amp;readfds);
    FD_SET(sockfd, &amp;readfds);

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

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

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

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

return 0;
</code></pre>
<p>}</p>
<p>#include <QWidget>
#include <QTcpSocket>
#include <QDebug>
#include <QByteArray>
#include <QTcpSocket></p>
<p>namespace Ui {
class Procession;
}</p>
<p>class Procession : public QWidget
{
Q_OBJECT</p>
<p>public:
explicit Procession(int userid,QWidget *parent = nullptr);
~Procession();
void processionWidget();</p>
<p>private slots:
//void on_pushButton_clicked();
void connected();
void disconnected();
void readyRead();
void displayError(QAbstractSocket::SocketError error);</p>
<pre><code>void on_connectBtn_clicked();
</code></pre>
<p>private:
Ui::Procession <em>ui;
int userid;
QTcpSocket</em> m_socket;
};</p>
<p>#endif // PROCESSION_H</p>
<p>客户端IP=127.0.0.1 Port=12345</p>
<p>root@WIN-K3C9KG85CB8:/home/SmartHome/Server# valgrind --leak-check=full ./main.exec
==3155== Memcheck, a memory error detector
==3155== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==3155== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==3155== Command: ./main.exec
==3155==
正在连接中...
建议发送成功！客户端已连接
userid:123
空调温度正常</p>
<p>客户端运行结果
正在连接中...
连接成功
解析服务器返回的数据失败
连接失败：远程主机关闭
连接失败</p>
<p>ifconfig运行结果
root@WIN-K3C9KG85CB8:/home/SmartHome/Server# ifconfig
eth0: flags=4163&lt;UP,BROADCAST,RUNNING,MULTICAST&gt;  mtu 1500
inet 172.21.91.176  netmask 255.255.240.0  broadcast 172.21.95.255
inet6 fe80::215:5dff:fedd:6558  prefixlen 64  scopeid 0x20<link>
ether 00:15:5d:dd:65:58  txqueuelen 1000  (Ethernet)
RX packets 11543  bytes 15485605 (15.4 MB)
RX errors 0  dropped 0  overruns 0  frame 0
TX packets 2910  bytes 319768 (319.7 KB)
TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0</p>
<p>lo: flags=73&lt;UP,LOOPBACK,RUNNING&gt;  mtu 65536
inet 127.0.0.1  netmask 255.0.0.0
inet6 ::1  prefixlen 128  scopeid 0x10<host>
loop  txqueuelen 1000  (Local Loopback)
RX packets 511  bytes 31391 (31.3 KB)
RX errors 0  dropped 0  overruns 0  frame 0
TX packets 511  bytes 31391 (31.3 KB)
TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0</p>
<p>如何解决</p>
<p>客户端地址已设置成172.21.91.176</p>
<p>服务器运行结果
root@WIN-K3C9KG85CB8:/home/SmartHome/Server# valgrind --leak-check=full ./main.exec
==3194== Memcheck, a memory error detector
==3194== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==3194== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==3194== Command: ./main.exec
==3194==
正在连接中...
建议发送成功！客户端已连接
userid:123
空调温度正常</p>
<p>第二次点击客户端按键时服务器运行结果
客户端已连接
userid:123
空调温度正常
第三次点击客户端按键服务器运行结果
客户端已连接
userid:123
空调温度正常</p>
<p>客户端运行结果一直是下面这样
正在连接中...
连接成功
解析服务器返回的数据失败
连接失败：远程主机关闭
连接失败</p>
<p>客户端解析服务器发来的消息的代码
void Procession::readyRead()
{
QByteArray data = m_socket-&gt;readAll();
if (data.isEmpty()) {
ui-&gt;message-&gt;append('读取的数据为空');
return;
}
// 解析服务器返回的数据
QDataStream in(&amp;data, QIODevice::ReadOnly);
QString suggestion;
in &gt;&gt; suggestion; // 使用重载的 &gt;&gt; 运算符来读取数据
if (in.status() != QDataStream::Ok) {
ui-&gt;message-&gt;append('解析服务器返回的数据失败');
return;
}
ui-&gt;message-&gt;append(suggestion);
m_socket-&gt;close();
}</p>
<p>客户端运行结果
正在连接中...
连接成功
连接失败</p>
<p>有什么问题，该如何解决</p>
<p>客户端代码更改为：
#include 'procession.h'
#include 'ui_procession.h'
#include <QAbstractSocket>
#include <QDebug></p>
<p>Procession::Procession(int userid,QWidget *parent) :
QWidget(parent),
ui(new Ui::Procession),
userid(userid)
{
ui-&gt;setupUi(this);
processionWidget();
m_socket = new QTcpSocket(this);
//connect(ui-&gt;connectBtn, &amp;QPushButton::clicked, this, &amp;Procession::on_connectBtn_clicked);
connect(m_socket, &amp;QTcpSocket::readyRead, this, &amp;Procession::readyRead);
connect(m_socket, &amp;QTcpSocket::connected, this, &amp;Procession::connected);
connect(m_socket, &amp;QTcpSocket::disconnected,this,&amp;Procession::disconnected);
connect(m_socket, QOverload<a href="QAbstractSocket::SocketError">QAbstractSocket::SocketError</a>::of(&amp;QTcpSocket::error), this, &amp;Procession::displayError);
}</p>
<p>Procession::~Procession()
{
delete ui;
// 在程序结束前关闭套接字
m_socket-&gt;close();
}</p>
<p>void Procession::processionWidget()
{
setWindowTitle('服务器通信');
setAutoFillBackground(true);
QPalette palette=this-&gt;palette();
QPixmap pixmap(':/user/image/image/net.jpg');
palette.setBrush(QPalette::Window, QBrush(pixmap));
setPalette(palette);
setFixedSize(600,400);
}</p>
<p>void Procession::connected()
{
ui-&gt;message-&gt;append('连接成功');
QByteArray block;
QDataStream out(&amp;block, QIODevice::WriteOnly);
out &lt;&lt; static_cast<quint32>(this-&gt;userid);
qDebug()&lt;&lt;static_cast<quint32>(this-&gt;userid);
if (m_socket-&gt;write(block) == -1) {
ui-&gt;message-&gt;append('发送userid失败');
m_socket-&gt;close();
}
}</p>
<p>void Procession::disconnected()
{
ui-&gt;message-&gt;append('连接失败');
m_socket-&gt;close();
}</p>
<p>void Procession::readyRead()
{
QByteArray data = m_socket-&gt;readAll();
if (data.isEmpty()) {
ui-&gt;message-&gt;append('读取的数据为空');
return;
}
else{
ui-&gt;message-&gt;append('可以读取到服务器的数据');
}
// 解析服务器返回的数据
QDataStream in(&amp;data, QIODevice::ReadOnly);
QString suggestion;
in &gt;&gt; suggestion; // 使用重载的 &gt;&gt; 运算符来读取数据
ui-&gt;message-&gt;append(suggestion);
if (in.status() != QDataStream::Ok) {
ui-&gt;message-&gt;append('解析服务器返回的数据失败');
return;
}
ui-&gt;message-&gt;append(suggestion);
m_socket-&gt;close();
}</p>
<p>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-&gt;message-&gt;append('连接失败：' + errorMessage);
}</p>
<p>void Procession::on_connectBtn_clicked()
{
if (m_socket-&gt;state() == QAbstractSocket::ConnectedState) {
m_socket-&gt;disconnectFromHost(); // 先关闭套接字
}</p>
<pre><code>ui-&gt;message-&gt;append('已经连接上服务器');
QString ip = ui-&gt;IP-&gt;text();
QString port = ui-&gt;port-&gt;text();

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

ui-&gt;message-&gt;clear();
ui-&gt;message-&gt;append('正在连接中...');
m_socket-&gt;connectToHost(ip, static_cast&lt;quint16&gt;(ui-&gt;port-&gt;text().toInt()));
</code></pre>
<p>}</p>
<p>客户端运行结果
正在连接中...
连接成功
可以读取到服务器的数据</p>
<p>解析服务器返回的数据失败
连接失败：远程主机关闭
连接失败</p>
<p>如何解决
内容：在客户端代码中，解析服务器返回的数据时，使用了QDataStream的读取操作符&gt;&gt;。但是在服务器端代码中，发送的数据是一个字符串，而不是QDataStream格式的数据。因此，在客户端代码中，应该使用QString类型的变量来接收服务器发送的数据，而不是QDataStream类型的变量。</p>
<p>修改客户端代码的readyRead()函数如下：</p>
<p>void Procession::readyRead()
{
QByteArray data = m_socket-&gt;readAll();
if (data.isEmpty()) {
ui-&gt;message-&gt;append('读取的数据为空');
return;
}
else{
ui-&gt;message-&gt;append('可以读取到服务器的数据');
}
// 解析服务器返回的数据
QString suggestion = QString::fromUtf8(data);
ui-&gt;message-&gt;append(suggestion);
m_socket-&gt;close();
}</p>
<p>这样修改后，客户端就能正确解析服务器返回的数据了。</p>
C++ 智能家居系统：基于套接字和 SQLite 的设备状态监测与建议生成

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

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