linux c++ 日志类

#include <iostream>
#include <fstream>
#include <ctime>
#include <string>

class Logger {
public:
    enum LogLevel { DEBUG, INFO, WARNING, ERROR, CRITICAL };

    Logger(const std::string& filename) : logFile(filename, std::ios::app) {
        if (!logFile.is_open()) {
            throw std::runtime_error("Unable to open log file");
        }
    }

    ~Logger() {
        if (logFile.is_open()) {
            logFile.close();
        }
    }

    void log(LogLevel level, const std::string& message) {
        std::time_t now = std::time(nullptr);
        std::string levelStr;
        switch (level) {
            case DEBUG:   levelStr = "DEBUG";   break;
            case INFO:    levelStr = "INFO";    break;
            case WARNING: levelStr = "WARNING"; break;
            case ERROR:   levelStr = "ERROR";   break;
            case CRITICAL: levelStr = "CRITICAL"; break;
        }
        logFile << "[" << std::ctime(&now) << "] " << levelStr << ": " << message << std::endl;
    }

private:
    std::ofstream logFile;
};

int main() {
    try {
        Logger logger("app.log");
        logger.log(Logger::INFO, "Application started.");
        // ... 其他代码 ...
        logger.log(Logger::ERROR, "An error occurred!");
    } catch (const std::exception& e) {
        std::cerr << "Logging failed: " << e.what() << std::endl;
    }
    return 0;
}