如何用Golang开发简单的日历应用_Golang 日历应用开发实践

func printCalendar(year int, month time.Month) {
    first := time.Date(year, month, 1, 0, 0, 0, 0, time.Local)
    weekday := int(first.Weekday())
    daysInMonth := first.AddDate(0, 1, -1).Day()

    fmt.Println("Su Mo Tu We Th Fr Sa")
    for i := 0; i < weekday; i++ {
        fmt.Print("   ")
    }
    for day := 1; day <= daysInMonth; day++ {
        fmt.Printf("%2d ", day)
        if (day + weekday) % 7 == 0 {
            fmt.Println()
        }
    }
    if (daysInMonth+weekday)%7 != 0 {
        fmt.Println()
    }
}

func main() {
    now := time.Now()
    year, month := now.Year(), now.Month()

    if len(os.Args) == 3 {
        var err error
        year, err = strconv.Atoi(os.Args[1])
        if err != nil {
            log.Fatal("无效的年份")
        }
        m, err := strconv.Atoi(os.Args[2])
        if err != nil || m < 1 || m > 12 {
            log.Fatal("无效的月份")
        }
        month = time.Month(m)
    }

    printCalendar(year, month)
}

http.HandleFunc("/calendar", func(w http.ResponseWriter, r *http.Request) {
    yearStr := r.URL.Query().Get("year")
    monthStr := r.URL.Query().Get("month")

    year, _ := strconv.Atoi(yearStr)
    month, _ := strconv.Atoi(monthStr)

    if year == 0 {
        year = time.Now().Year()
    }
    if month == 0 {
        month = int(time.Now().Month())
    }

    w.Header().Set("Content-Type", "text/plain")
    var oldStdout = os.Stdout
    os.Stdout = w // 注意：此处仅为演示逻辑，实际应缓冲输出
    printCalendar(year, time.Month(month))
})

var events = map[string][]string{
    "2025-04-01": {"清明节"},
    "2025-04-30": {"项目截止"},
}