Java 獲取 Unix時間戳

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

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

但是，因為需求是需要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;
	}

 從新封裝了一些方法。如下穩定性就好很多了。

package com.xuanyuan.utils;

public class TimeUtils {
    
      /**
     * Constant that contains the amount of milliseconds in a second
     */
    static final long ONE_SECOND = 1000L;

    /**
     * Converts milliseconds to seconds
     * @param timeInMillis
     * @return The equivalent time in seconds
     */
    public static int toSecs(long timeInMillis) {
        // Rounding the result to the ceiling, otherwise a
        // System.currentTimeInMillis that happens right before a new Element
        // instantiation will be seen as 'later' than the actual creation time
        return (int)Math.ceil((double)timeInMillis / ONE_SECOND);
    }

    /**
     * Converts seconds to milliseconds, with a precision of 1 second
     * @param timeInSecs the time in seconds
     * @return The equivalent time in milliseconds
     */
    public static long toMillis(int timeInSecs) {
        return timeInSecs * ONE_SECOND;
    }

    /**
     * Converts a long seconds value to an int seconds value and takes into account overflow
     * from the downcast by switching to Integer.MAX_VALUE.
     * @param seconds Long value
     * @return Same int value unless long > Integer.MAX_VALUE in which case MAX_VALUE is returned
     */
    public static int convertTimeToInt(long seconds) {
        if (seconds > Integer.MAX_VALUE) {
            return Integer.MAX_VALUE;
        } else {
            return (int) seconds;
        }
    }

}