Qt 客户端与 C 服务器通信：使用 JSON 和 SQLite 数据库进行温度湿度信息交互

#ifndef PROCESSION_H #define PROCESSION_H

#include #include #include

namespace Ui { class Procession; }

class Procession : public QWidget { Q_OBJECT

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

private slots: void connectToServer(); void handleServerResponse(QNetworkReply *reply);

private: Ui::Procession *ui; int userid; QNetworkAccessManager *networkManager;

void processionWidget();
QByteArray createRequestData();

};

#endif // PROCESSION_H

#include "procession.h" #include "ui_procession.h" #include #include #include

Procession::Procession(int userid, QWidget *parent) : QWidget(parent), ui(new Ui::Procession), userid(userid) { ui->setupUi(this); processionWidget(); networkManager = new QNetworkAccessManager(this); connect(ui->connectServerBtn, &QPushButton::clicked, this, &Procession::connectToServer); connect(networkManager, &QNetworkAccessManager::finished, this, &Procession::handleServerResponse); }

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::connectToServer() { QByteArray requestData = createRequestData();

QNetworkRequest request(QUrl(ui->serverIP->text()));
request.setHeader(QNetworkRequest::ContentTypeHeader, 'application/json');

networkManager->post(request, requestData);

}

void Procession::handleServerResponse(QNetworkReply *reply) { if (reply->error() == QNetworkReply::NoError) { QByteArray responseData = reply->readAll(); ui->message->append(responseData); } else { ui->message->append('连接失败！'); }

reply->deleteLater();

}

QByteArray Procession::createRequestData() { QJsonObject json; json['userid'] = this->userid;

QJsonDocument doc(json);
return doc.toJson();

}

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sqlite3.h> #include <stdbool.h> #include <unistd.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <json-c/json.h>

#define DATABASE "database.db" #define PORT 8080

struct Status { int sid; // 状态ID int uid; // 用户ID char device_name[10]; // 设备名称 char device_state[10]; // 设备状态 char value[10]; // 值 char mode[10]; // 模式 };

void handleClientRequest(int clientSocket); // 处理客户端请求 void handleTemperatureHumidity(int clientSocket, int uid); // 处理温度湿度请求 void sendResponse(int clientSocket, const char* response); // 发送响应 char* getAdvice(int temperature, int humidity); // 获取建议

static sqlite3* db = NULL; // 静态变量存储数据库连接

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

// 打开数据库连接
int rc = sqlite3_open(DATABASE, &db);
if (rc != SQLITE_OK) {
    perror('打开数据库出错');
    exit(1);
}

// 创建套接字
serverSocket = socket(AF_INET, SOCK_STREAM, 0);
if (serverSocket < 0) {
    perror('创建套接字出错');
    exit(1);
}

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

// 将套接字绑定到指定的地址和端口
if (bind(serverSocket, (struct sockaddr*)&serverAddress, sizeof(serverAddress)) < 0) {
    perror('绑定套接字出错');
    exit(1);
}

// 监听传入连接
if (listen(serverSocket, 5) < 0) {
    perror('监听连接出错');
    exit(1);
}

printf('服务器已启动。正在监听端口 %d...

', PORT);

while (true) {
    // 接受客户端连接
    clientSocket = accept(serverSocket, (struct sockaddr*)&clientAddress, &clientAddressLength);
    if (clientSocket < 0) {
        perror('接受连接出错');
        exit(1);
    }

    printf('客户端已连接，来自 %s:%d

', inet_ntoa(clientAddress.sin_addr), ntohs(clientAddress.sin_port));

    // 处理客户端请求
    handleClientRequest(clientSocket);

    // 关闭客户端连接
    close(clientSocket);
    printf('客户端已断开连接

'); }

// 关闭服务器套接字
close(serverSocket);

// 关闭数据库连接
sqlite3_close(db);

return 0;

}

void handleClientRequest(int clientSocket) { char buffer[1024]; int bytesRead = read(clientSocket, buffer, sizeof(buffer)); if (bytesRead < 0) { perror('从套接字读取数据出错'); exit(1); }

// 解析JSON请求
struct json_object* jsonRequest = json_tokener_parse(buffer);
if (jsonRequest == NULL) {
    perror('解析JSON出错');
    exit(1);
}

// 从JSON请求中获取用户ID
struct json_object* jsonUserID;
json_object_object_get_ex(jsonRequest, 'userid', &jsonUserID);
int uid = json_object_get_int(jsonUserID);

// 处理温度湿度请求
handleTemperatureHumidity(clientSocket, uid);

// 清理资源
json_object_put(jsonRequest);

}

void handleTemperatureHumidity(int clientSocket, int uid) { char query[100]; snprintf(query, sizeof(query), 'SELECT * FROM Status WHERE uid = %d', uid);

sqlite3_stmt* stmt;
int rc = sqlite3_prepare_v2(db, query, -1, &stmt, 0);
if (rc != SQLITE_OK) {
    perror('准备SQL语句出错');
    exit(1);
}

// 获取用户的最新温度和湿度值
int temperature = 0;
int humidity = 0;

while (sqlite3_step(stmt) == SQLITE_ROW) {
    struct Status status;
    status.sid = sqlite3_column_int(stmt, 0);
    status.uid = sqlite3_column_int(stmt, 1);
    strcpy(status.device_name, (char*)sqlite3_column_text(stmt, 2));
    strcpy(status.device_state, (char*)sqlite3_column_text(stmt, 3));
    strcpy(status.value, (char*)sqlite3_column_text(stmt, 4));
    strcpy(status.mode, (char*)sqlite3_column_text(stmt, 5));

    if (strcmp(status.device_name, 'Temperature') == 0) {
        temperature = atoi(status.value);
    } else if (strcmp(status.device_name, 'Humidity') == 0) {
        humidity = atoi(status.value);
    }
}

// 根据温度和湿度值获取建议
char* advice = getAdvice(temperature, humidity);

// 将建议发送给客户端
sendResponse(clientSocket, advice);

// 清理资源
sqlite3_finalize(stmt);

}

void sendResponse(int clientSocket, const char* response) { int bytesWritten = write(clientSocket, response, strlen(response)); if (bytesWritten < 0) { perror('写入套接字出错'); exit(1); } }

char* getAdvice(int temperature, int humidity) { char* advice = (char*)malloc(100);

if (temperature < 24) {
    snprintf(advice, 100, '温度过低，请将温度调高至 26°C。');
} else if (humidity < 40 || humidity > 70) {
    snprintf(advice, 100, '湿度过高或过低，请调整湿度水平。');
} else {
    snprintf(advice, 100, '暂无建议。');
}

return advice;

}