在Java中创建一个GUID

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Chris Dutrow

问题

在Java中创建一个GUID

在Java中创建GUID的最佳方式有哪些？

Valeriu 50848

已编辑的问题 5日十月 2021 в 8:39

Boann

已编辑的问题 18日十一月 2015 в 5:55

编程

java

guid

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解决方案/答案

Anton Belev

10日十月 2016 в 9:37

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只是用一个例子来扩展Mark Byers'的答案。

import java.util.UUID;

public class RandomStringUUID {
    public static void main(String[] args) {
        UUID uuid = UUID.randomUUID();
        System.out.println("UUID=" + uuid.toString() );
    }
}

Anton Belev

编辑本段答案18日七月 2019 в 12:42

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user2044181

27日十一月 2017 в 3:48

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您可以使用这段代码来生成GUID。

 import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;

public class StrictMicroSecondTimeBasedGuid
{
    private final static Logger logger = Logger
            .getLogger(StrictMicroSecondTimeBasedGuid.class);

    private static final long MICRO_IN_MILL = 1000;
    private static final long NANO_IN_MICRO = 1000;

    private static long baseNanoTime;
    private static long baseTimeInMicro;
    private static long lastGuid;

    static
    {
        /*
         * Nanosecond time's reference is not known, therfore following logic is
         * needed to calculate time in micro without knowing refrence point of
         * nano time*
         */
        baseNanoTime = System.nanoTime();
        baseTimeInMicro = System.currentTimeMillis() * MICRO_IN_MILL;
        lastGuid = baseTimeInMicro;
    }

    public static synchronized Long newGuid()
    {
        long newGuid;

        while ((newGuid = calNewTimeInMicro()) <= lastGuid)
        {
            /** we have to check for this log, we don't want to see log. */

            logger.debug("wait of 10-microsecond is introduced to get new guid");

            try
            {
                TimeUnit.MICROSECONDS.sleep(10);
            } catch (InterruptedException e)
            {
                logger.error("Error", e);
            }
        }

        lastGuid = newGuid;
        return newGuid;
    }

    private static long calNewTimeInMicro()
    {
        return baseTimeInMicro
                + ((System.nanoTime() - baseNanoTime) / NANO_IN_MICRO);
    }
}

user2044181

编辑本段答案27日十一月 2017 в 4:17

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