Java 获取 Unix时间戳

unix时间戳是从1970年1月1日（UTC/GMT的午夜）开始所经过的秒数，不考虑闰秒。

在大多数的UNIX系统中UNIX时间戳存储为32位，这样会引发2038年问题。

但是，因为需求是需要int类型的UNIX时间戳。 开始的时候我是这样设计的。

/**
	 * 获取当前事件Unxi 时间戳
	 * @return
	 */
	public static int getUnixTimeStamp(){
		long rest=System.currentTimeMillis()/1000L;
		return (int)rest;
	}

 从新封装了一些方法。如下稳定性就好很多了。

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;
        }
    }

}