ios 时间戳转换成时间

+ (NSDate*)dateWithTimeIntervalInMilliSecondSince1970:(double)timeIntervalInMilliSecond {

    NSDate*ret = nil;

    doubletimeInterval = timeIntervalInMilliSecond;

    // judge if the argument is in secconds(for former data structure).

    if(timeIntervalInMilliSecond > 140000000000) {

        timeInterval = timeIntervalInMilliSecond / 1000;

    }

    ret = [NSDatedateWithTimeIntervalSince1970:timeInterval];

     

    returnret;

}