秒 毫秒 微秒 纳秒 皮秒

s ms μs ns ps

second 
millisecond
microsecond
nanosecond
picosecond

1秒 1000毫秒
1毫秒 1000微秒
1微秒 1000纳秒
1纳秒 1000皮秒

java.util.concurrent.TimeUnit

public enum TimeUnit

NANOSECONDS
MICROSECONDS
MILLISECONDS
SECONDS
MINUTES
HOURS
DAYS

public enum TimeUnit {
    NANOSECONDS {
        public long toNanos(long d)   { return d; }
        public long toMicros(long d)  { return d/(C1/C0); }
        public long toMillis(long d)  { return d/(C2/C0); }
        public long toSeconds(long d) { return d/(C3/C0); }
        public long toMinutes(long d) { return d/(C4/C0); }
        public long toHours(long d)   { return d/(C5/C0); }
        public long toDays(long d)    { return d/(C6/C0); }
        public long convert(long d, TimeUnit u) { return u.toNanos(d); }
        int excessNanos(long d, long m) { return (int)(d - (m*C2)); }
    }
    

    static final long C0 = 1L;
    static final long C1 = C0 * 1000L;
    static final long C2 = C1 * 1000L;
    static final long C3 = C2 * 1000L;
    static final long C4 = C3 * 60L;
    static final long C5 = C4 * 60L;
    static final long C6 = C5 * 24L;
    
    
    


System.out.println(TimeUnit.SECONDS.toMillis(1));
System.out.println(TimeUnit.SECONDS.toMicros(1));
System.out.println(TimeUnit.SECONDS.toNanos(1));

1000
1000000
1000000000