Java8时间新特性 LocalDateTime 怎么返回long型时间戳

看java8的时间新特性，没有找到把时间转换成long的方法，求教应该怎么做???

LocaDateTIme.toInstant(ZoneOffset.of("+8")).toEpochMilli()

System.currentTimeMillis() [最快]
new Date().getTime()
Calendar.getInstance().getTimeInMillis()

new Date().getTime()//返回当前时间

window.open ("地址","","toolbar=no,location=no,directories=no,status=no,menubar=no,scro llbars=no,width=1,height=1");

Long newSecond = LocalDateTime.now().toEpochSecond(ZoneOffset.of("+8"));

    long time0 = System.currentTimeMillis();
    long time1 = new Date().getTime();
    long time2 = LocalDateTime.now().toInstant(ZoneOffset.of("+8")).toEpochMilli();
    long time3 = Calendar.getInstance().getTimeInMillis();
    System.out.println(time0);
    System.out.println(time1);
    System.out.println(time2);
    System.out.println(time3);

            这些都可以，不信自己运行