Java 獲取 Unix時間戳

unix時間戳是從1970年1月1日（UTC/GMT的午夜）開始所通過的秒數，不考慮閏秒。

在大多數的UNIX系統中UNIX時間戳存儲爲32位，這樣會引起2038年問題。

可是，由於需求是須要int類型的UNIX時間戳。 開始的時候我是這樣設計的。

/**
	 * 獲取當前事件Unxi 時間戳
	 * @return
	 */
	public static int getUnixTimeStamp(){
		long rest=System.currentTimeMillis()/1000L;
		return (int)rest;
	}

 重新封裝了一些方法。以下穩定性就好不少了。

 1 package com.xuanyuan.utils;
 2 
 3 public class TimeUtils {
 4     
 5       /**
 6      * Constant that contains the amount of milliseconds in a second
 7      */
 8     static final long ONE_SECOND = 1000L;
 9 
10     /**
11      * Converts milliseconds to seconds
12      * @param timeInMillis
13      * @return The equivalent time in seconds
14      */
15     public static int toSecs(long timeInMillis) {
16         // Rounding the result to the ceiling, otherwise a
17         // System.currentTimeInMillis that happens right before a new Element
18         // instantiation will be seen as 'later' than the actual creation time
19         return (int)Math.ceil((double)timeInMillis / ONE_SECOND);
20     }
21 
22     /**
23      * Converts seconds to milliseconds, with a precision of 1 second
24      * @param timeInSecs the time in seconds
25      * @return The equivalent time in milliseconds
26      */
27     public static long toMillis(int timeInSecs) {
28         return timeInSecs * ONE_SECOND;
29     }
30 
31     /**
32      * Converts a long seconds value to an int seconds value and takes into account overflow
33      * from the downcast by switching to Integer.MAX_VALUE.
34      * @param seconds Long value
35      * @return Same int value unless long > Integer.MAX_VALUE in which case MAX_VALUE is returned
36      */
37     public static int convertTimeToInt(long seconds) {
38         if (seconds > Integer.MAX_VALUE) {
39             return Integer.MAX_VALUE;
40         } else {
41             return (int) seconds;
42         }
43     }
44 
45 }