現(xiàn)在的Unix時(shí)間戳是：1484289773
什么是時(shí)間戳？
Unix時(shí)間戳(Unix timestamp)，或稱(chēng)Unix時(shí)間(Unix time)、POSIX時(shí)間(POSIX time)，是一種時(shí)間表示方式，定義為從格林威治時(shí)間1970年01月01日00時(shí)00分00秒起至現(xiàn)在的總秒數(shù)。Unix時(shí)間戳不僅被使用在Unix系統(tǒng)、類(lèi)Unix系統(tǒng)中，也在許多其他操作系統(tǒng)中被廣泛采用。多數(shù)Unix系統(tǒng)將時(shí)間戳以一個(gè)32位整型進(jìn)行保存，這可能會(huì)在2038年1月19日產(chǎn)生一些問(wèn)題（Y2038問(wèn)題）。
如何在不同編程語(yǔ)言中 獲取現(xiàn)在的Unix時(shí)間戳(Unix timestamp)？
| Java | time |
| JavaScript | Math.round(new Date().getTime()/1000) getTime()返回?cái)?shù)值的單位是毫秒 |
| Microsoft .NET / C# | epoch = (DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000 |
| MySQL | SELECT unix_timestamp(now()) |
| Perl | time |
| PHP | time() |
| PostgreSQL | SELECT extract(epoch FROM now()) |
| Python | 先 import time 然后 time.time() |
| Ruby | 獲取Unix時(shí)間戳：Time.now 或 Time.new 顯示Unix時(shí)間戳：Time.now.to_i |
| SQL Server | SELECT DATEDIFF(s, '1970-01-01 00:00:00', GETUTCDATE()) |
| Unix / Linux | date +%s |
| VBScript / ASP | DateDiff("s", "01/01/1970 00:00:00", Now()) |
| 其他操作系統(tǒng) (如果Perl被安裝在系統(tǒng)中) |
命令行狀態(tài)：perl -e "print time" |
如何在不同編程語(yǔ)言中 實(shí)現(xiàn)Unix時(shí)間戳(Unix timestamp) → 普通時(shí)間？
| Java | String date = new java.text.SimpleDateFormat("dd/MM/yyyy HH:mm:ss").format(new java.util.Date(Unix timestamp * 1000)) |
| JavaScript | 先 var unixTimestamp = new Date(Unix timestamp * 1000) 然后 commonTime = unixTimestamp.toLocaleString() |
| Linux | date -d @Unix timestamp |
| MySQL | from_unixtime(Unix timestamp) |
| Perl | 先 my $time = Unix timestamp 然后 my ($sec, $min, $hour, $day, $month, $year) = (localtime($time))[0,1,2,3,4,5,6] |
| PHP | date('r', Unix timestamp) |
| PostgreSQL | SELECT TIMESTAMP WITH TIME ZONE 'epoch' + Unix timestamp) * INTERVAL '1 second'; |
| Python | 先 import time 然后 time.gmtime(Unix timestamp) |
| Ruby | Time.at(Unix timestamp) |
| SQL Server | DATEADD(s, Unix timestamp, '1970-01-01 00:00:00') |
| VBScript / ASP | DateAdd("s", Unix timestamp, "01/01/1970 00:00:00") |
| 其他操作系統(tǒng) (如果Perl被安裝在系統(tǒng)中) |
命令行狀態(tài)：perl -e "print scalar(localtime(Unix timestamp))" |
如何在不同編程語(yǔ)言中 實(shí)現(xiàn)普通時(shí)間 → Unix時(shí)間戳(Unix timestamp)？
| Java | long epoch = new java.text.SimpleDateFormat("dd/MM/yyyy HH:mm:ss").parse("01/01/1970 01:00:00"); |
| JavaScript | var commonTime = new Date(Date.UTC(year, month - 1, day, hour, minute, second)) |
| MySQL | SELECT unix_timestamp(time) 時(shí)間格式: YYYY-MM-DD HH:MM:SS 或 YYMMDD 或 YYYYMMDD |
| Perl | 先 use Time::Local 然后 my $time = timelocal($sec, $min, $hour, $day, $month, $year); |
| PHP | mktime(hour, minute, second, month, day, year) |
| PostgreSQL | SELECT extract(epoch FROM date('YYYY-MM-DD HH:MM:SS')); |
| Python | 先 import time 然后 int(time.mktime(time.strptime('YYYY-MM-DD HH:MM:SS', '%Y-%m-%d %H:%M:%S'))) |
| Ruby | Time.local(year, month, day, hour, minute, second) |
| SQL Server | SELECT DATEDIFF(s, '1970-01-01 00:00:00', time) |
| Unix / Linux | date +%s -d"Jan 1, 1970 00:00:01" |
| VBScript / ASP | DateDiff("s", "01/01/1970 00:00:00", time) |
