Shulou(Shulou.com)06/01 Report--

In this article, the editor introduces in detail "how Java generates ID through handwritten distributed snowflake SnowFlake". The content is detailed, the steps are clear, and the details are handled properly. I hope this "Java how to generate ID through handwritten distributed snowflake SnowFlake" article can help you solve your doubts.

SnowFlake algorithm

The result of id generated by SnowFlake algorithm is an integer of 64bit size, which has the following structure:

It is divided into four paragraphs:

The first paragraph: 1 bit is unused, always fixed to 0.

(because the highest bit in binary is the sign bit, 1 represents a negative number and 0 represents a positive number. The generated id is usually a positive integer, so the highest bit is fixed to 0)

Second paragraph: 41 bits are millisecond time (41 bits can be used for 69 years)

The third paragraph: 10-bit workerId (10-bit length supports deployment of up to 1024 nodes)

(the 10 bits here are divided into two parts, the first part 5 bits represent the data center ID (0-31), the second part 5 bits represent the machine ID (0-31))

Paragraph 4: 12-bit count within milliseconds (12-bit counting sequence numbers support 4096 ID sequence numbers per node per millisecond)

Code implementation:

Import java.util.HashSet;import java.util.concurrent.atomic.AtomicLong;public class SnowFlake {/ / time 41-bit private static long lastTime = System.currentTimeMillis (); / / data center ID 5-bit (default 0-31) private long datacenterId = 0; private long datacenterIdShift = 5; / / computer room machine ID 5-bit (default 0-31) private long workerId = 0; private long workerIdShift = 5 / / 12-digit random number (default 0,4095) private AtomicLong random = new AtomicLong (); private long randomShift = 12; / / maximum random number private long maxRandom = (long) Math.pow (2, randomShift); public SnowFlake () {} public SnowFlake (long workerIdShift, long datacenterIdShift) {if (workerIdShift)

22) {throw new IllegalArgumentException ("parameter mismatch");} this.workerIdShift = workerIdShift; this.datacenterIdShift = datacenterIdShift; this.randomShift = 22-datacenterIdShift-workerIdShift; this.maxRandom = (long) Math.pow (2, randomShift);} / / get ID private long getId () {return lastTime of snowflake

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.