Generator - java generates 18-digit unique id

Question

Each Alipay coupon has an 18-digit integer ID, and the consumption code on WeChat's coupon is 12 digits. I would like to know how this 18-digit unique ID is generated. Aren't they generally 64-bit? Or UUiD

Answer 1

http://www.wangtao.pw/admin/d... Use java to generate pure numeric unique IDs (no database involved. Customized number of digits)

Answer 2

You can read this article from Meituan, it should be helpful to you http://tech.meituan.com/MT_Le...