mybatis雪花算法工具类

Sure! Here's an example implementation of a MyBatis Snowflake algorithm utility class in Java:

import java.util.Calendar;

public class SnowflakeUtils {

    private final static long START_STAMP = 1480166465631L;
    private final static long SEQUENCE_BIT = 12;
    private final static long MACHINE_BIT = 10;
    private final static long MAX_SEQUENCE = -1L ^ (-1L << SEQUENCE_BIT);
    private final static long MACHINE_ID = getMachineId();

    private static long lastTimestamp = -1L;
    private static long sequence = 0L;

    private static synchronized long nextId() {
        long timestamp = timeGen();
        if (timestamp < lastTimestamp) {
            throw new RuntimeException("Clock moved backwards. Refusing to generate id.");
        }

        if (timestamp == lastTimestamp) {
            sequence = (sequence + 1) & MAX_SEQUENCE;
            if (sequence == 0) {
                timestamp = tilNextMillis(lastTimestamp);
            }
        } else {
            sequence = 0L;
        }

        lastTimestamp = timestamp;
        return ((timestamp - START_STAMP) << (SEQUENCE_BIT + MACHINE_BIT)) | (MACHINE_ID << SEQUENCE_BIT) | sequence;
    }

    private static long tilNextMillis(long lastTimestamp) {
        long timestamp = timeGen();
        while (timestamp <= lastTimestamp) {
            timestamp = timeGen();
        }
        return timestamp;
    }

    private static long timeGen() {
        return Calendar.getInstance().getTimeInMillis();
    }

    private static long getMachineId() {
        // Replace this with logic to get a unique machine id
        return 1L;
    }

    public static void main(String[] args) {
        for (int i = 0; i < 10; i++) {
            System.out.println("Generated ID: " + nextId());
        }
    }
}

This utility class implements the Snowflake algorithm, which is a widely-used algorithm for generating unique IDs in a distributed system. The `nextId()` method generates the IDs based on the configured machine id and the current timestamp.

Please note that the `getMachineId()` method needs to be implemented according to your specific environment to obtain a unique machine id. This can be done based on the network configuration of your machines, or you can use other methods such as reading a hardware identifier.

You can run the `main` method to test the implementation and see generated IDs.