golang 使用time包获取时间戳与日期格式化操作

const (
 January Month = 1 + iota
 February
 March
 April
 May
 June
 July
 August
 September
 October
 November
 December
)

const (
 Sunday Weekday = iota
 Monday
 Tuesday
 Wednesday
 Thursday
 Friday
 Saturday
)

const (
 Nanosecond Duration = 1
 Microsecond   = 1000 * Nanosecond
 Millisecond   = 1000 * Microsecond
 Second    = 1000 * Millisecond
 Minute    = 60 * Second
 Hour     = 60 * Minute
)

fmt.Println(time.Now()) 
// 输出: 2019-04-30 14:41:59.661602 +0800 CST m=+0.000225294

fmt.Println(time.Now().String()) 
// 输出: 2019-04-30 14:41:59.661826 +0800 CST m=+0.000448434

// 获取当前unix时间戳（秒）
fmt.Println(time.Now().Unix()) // 输出: 1556615702

// 获取当前unix时间戳（毫秒）
fmt.Println(time.Now().UnixNano() / 1e6) // 输出: 1556615702009

// 获取当前unix时间戳（纳秒）
fmt.Println(time.Now().UnixNano()) // 输出: 1556615702009257000

x := "2018-12-27 18:44:55"
p, _ := time.Parse("2006-01-02 15:04:05", x)
fmt.Println( p.Unix() ) // 输出: 1545936295

t = time.Now()
fmt.Println(t.Format("2006-01-02"))   // 输出: 2019-04-30
fmt.Println(t.Format("2006-01-02 15:04:05")) // 输出: 2019-04-30 14:43:26
fmt.Println(t.Format("2006-01-02 00:00:00")) // 输出: 2019-04-30 00:00:00
fmt.Println(t.Format("2006/01/02 15:04")) // 输出: 2019-04-30 14:43
fmt.Println(t.Format("2006/Jan/02 15:04")) // 输出: 2019/Apr/30 17:28

// 指定时间
t2 := time.Date(2019, time.November, 28, 11, 35, 46, 0, time.UTC) 
// 返回 Time 类型

fmt.Printf("=>日期格式: %s\n", t2.Format("06/01/02 15:04:05")) 
// 输出: =>日期格式: 19/11/28 11:35:46

// Date()返回三个参数: 年月日
year1, month1, day1 := time.Now().Date()

fmt.Printf("year: %v, type: %T \n", year1, year1) 
// 输出: year: 2019, type: int 

fmt.Printf("month: %v, type: %T \n", month1, month1) 
// 输出: month: April, type: time.Month 

fmt.Printf("day: %v, type: %T \n", day1, day1) 
// 输出: day: 30, type: int 

// String returns the time formatted using the format string
// "2006-01-02 15:04:05.999999999 -0700 MST"
func (t Time) String() string {
 return t.Format("2006-01-02 15:04:05.999999999 -0700 MST")
}

func nowTime() string {
 return time.Now().Format("2006-01-02 15:04:05")
}