关于Unix时间戳(Unix timestamp)

悠悠 2022-05-19 09:58 335阅读 0赞

时间戳是自 1970 年 1 月 1 日（00:00:00 GMT）以来的秒数。它也被称为 Unix 时间戳（Unix Timestamp）。  
  
　　Unix时间戳(Unix timestamp)，或称Unix时间(Unix time)、POSIX时间(POSIX time)，是一种时间表示方式，定义为从格林威治时间1970年01月01日00时00分00秒起至现在的总秒数。Unix时间戳不仅被使用在Unix系统、类Unix系统中，也在许多其他操作系统中被广泛采用。

### 如何在不同编程语言中获取现在的Unix时间戳(Unix timestamp)？ ###

<table> 
 <tbody> 
  <tr> 
   <td>Java</td> 
   <td>time</td> 
  </tr> 
  <tr> 
   <td>JavaScript</td> 
   <td>Math.round(new Date().getTime()/1000)<br> getTime()返回数值的单位是毫秒</td> 
  </tr> 
  <tr> 
   <td>Microsoft .NET / C#</td> 
   <td>epoch = (DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000</td> 
  </tr> 
  <tr> 
   <td>MySQL</td> 
   <td>SELECT unix_timestamp(now())</td> 
  </tr> 
  <tr> 
   <td>Perl</td> 
   <td>time</td> 
  </tr> 
  <tr> 
   <td>PHP</td> 
   <td>time()</td> 
  </tr> 
  <tr> 
   <td>PostgreSQL</td> 
   <td>SELECT extract(epoch FROM now())</td> 
  </tr> 
  <tr> 
   <td>Python</td> 
   <td>先 import time 然后 time.time()</td> 
  </tr> 
  <tr> 
   <td>Ruby</td> 
   <td>获取Unix时间戳：Time.now 或 Time.new<br> 显示Unix时间戳：Time.now.to_i</td> 
  </tr> 
  <tr> 
   <td>SQL Server</td> 
   <td>SELECT DATEDIFF(s, '1970-01-01 00:00:00', GETUTCDATE())</td> 
  </tr> 
  <tr> 
   <td>Unix / Linux</td> 
   <td>date +%s</td> 
  </tr> 
  <tr> 
   <td>VBScript / ASP</td> 
   <td>DateDiff("s", "01/01/1970 00:00:00", Now())</td> 
  </tr> 
  <tr> 
   <td>其他操作系统<br> (如果Perl被安装在系统中)</td> 
   <td>命令行状态：perl -e "print time"</td> 
  </tr> 
 </tbody> 
</table>

### 如何在不同编程语言中实现Unix时间戳(Unix timestamp) → 普通时间？ ###

<table> 
 <tbody> 
  <tr> 
   <td>Java</td> 
   <td>String date = new java.text.SimpleDateFormat("dd/MM/yyyy HH:mm:ss").format(new java.util.Date(Unix timestamp * 1000))</td> 
  </tr> 
  <tr> 
   <td>JavaScript</td> 
   <td>先 var unixTimestamp = new Date(Unix timestamp * 1000) 然后 commonTime = unixTimestamp.toLocaleString()</td> 
  </tr> 
  <tr> 
   <td>Linux</td> 
   <td>date -d @Unix timestamp</td> 
  </tr> 
  <tr> 
   <td>MySQL</td> 
   <td>from_unixtime(Unix timestamp)</td> 
  </tr> 
  <tr> 
   <td>Perl</td> 
   <td>先 my $time = Unix timestamp 然后 my ($sec, $min, $hour, $day, $month, $year) = (localtime($time))[0,1,2,3,4,5,6]</td> 
  </tr> 
  <tr> 
   <td>PHP</td> 
   <td>date('r', Unix timestamp)</td> 
  </tr> 
  <tr> 
   <td>PostgreSQL</td> 
   <td>SELECT TIMESTAMP WITH TIME ZONE 'epoch' + Unix timestamp) * INTERVAL '1 second';</td> 
  </tr> 
  <tr> 
   <td>Python</td> 
   <td>先 import time 然后 time.gmtime(Unix timestamp)</td> 
  </tr> 
  <tr> 
   <td>Ruby</td> 
   <td>Time.at(Unix timestamp)</td> 
  </tr> 
  <tr> 
   <td>SQL Server</td> 
   <td>DATEADD(s, Unix timestamp, '1970-01-01 00:00:00')</td> 
  </tr> 
  <tr> 
   <td>VBScript / ASP</td> 
   <td>DateAdd("s", Unix timestamp, "01/01/1970 00:00:00")</td> 
  </tr> 
  <tr> 
   <td>其他操作系统<br> (如果Perl被安装在系统中)</td> 
   <td>命令行状态：perl -e "print scalar(localtime(Unix timestamp))"</td> 
  </tr> 
 </tbody> 
</table>

### 如何在不同编程语言中实现普通时间 → Unix时间戳(Unix timestamp)？ ###

<table> 
 <tbody> 
  <tr> 
   <td>Java</td> 
   <td>long epoch = new java.text.SimpleDateFormat("dd/MM/yyyy HH:mm:ss").parse("01/01/1970 01:00:00");</td> 
  </tr> 
  <tr> 
   <td>JavaScript</td> 
   <td>var commonTime = new Date(Date.UTC(year, month - 1, day, hour, minute, second))</td> 
  </tr> 
  <tr> 
   <td>MySQL</td> 
   <td>SELECT unix_timestamp(time)<br> 时间格式: YYYY-MM-DD HH:MM:SS 或 YYMMDD 或 YYYYMMDD</td> 
  </tr> 
  <tr> 
   <td>Perl</td> 
   <td>先 use Time::Local 然后 my $time = timelocal($sec, $min, $hour, $day, $month, $year);</td> 
  </tr> 
  <tr> 
   <td>PHP</td> 
   <td>mktime(hour, minute, second, day, month, year)</td> 
  </tr> 
  <tr> 
   <td>PostgreSQL</td> 
   <td>SELECT extract(epoch FROM date('YYYY-MM-DD HH:MM:SS'));</td> 
  </tr> 
  <tr> 
   <td>Python</td> 
   <td>先 import time 然后 int(time.mktime(time.strptime('YYYY-MM-DD HH:MM:SS', '%Y-%m-%d %H:%M:%S')))</td> 
  </tr> 
  <tr> 
   <td>Ruby</td> 
   <td>Time.local(year, month, day, hour, minute, second)</td> 
  </tr> 
  <tr> 
   <td>SQL Server</td> 
   <td>SELECT DATEDIFF(s, '1970-01-01 00:00:00', time)</td> 
  </tr> 
  <tr> 
   <td>Unix / Linux</td> 
   <td>date +%s -d"Jan 1, 1970 00:00:01"</td> 
  </tr> 
  <tr> 
   <td>VBScript / ASP</td> 
   <td>DateDiff("s", "01/01/1970 00:00:00", time)</td> 
  </tr> 
 </tbody> 
</table>