用Java解析长整数

Question

I want to parse a timestamp, a Long number like 14655**56648041** . I want to create from this Long number two other Long numbers, One with the last four numbers 8041 and the second with 5664 . I can convert the number to String, use substring and then convert it again to Long, but I want to know if there is a cleaner way? I tried using % and / but didn't succeed.

Answer 1

最后4位数字是num % 1E4 ，前四个数字是(num % 1E8 - (num % 1E4)) / 1E4

Answer 2

There is. You can obtain the last four numbers by performing a modulo 10000 on the number:

long last4 = all%10000;

You can furthermore obtain the middle four digits by first dividing by 10000 and the again perform modulo:

long midl4 = (all/10000)%10000;

Or putting it all together:

long all = 1465556648041L;

long last4 = all%10000;
long midl4 = (all/10000)%10000;

System.out.println("all="+all);
System.out.println("last4="+last4);
System.out.println("midl4="+midl4);

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