这取决于你想要什么样的UUID。

The standard Java UUID class generates Version 4 (random) UUIDs. (UPDATE - Version 3 (name) UUIDs can also be generated.) It can also handle other variants, though it cannot generate them. (In this case, "handle" means construct UUID instances from long, byte[] or String representations, and provide some appropriate accessors.) The Java UUID Generator (JUG) implementation purports to support "all 3 'official' types of UUID as defined by RFC-4122" ... though the RFC actually defines 4 types and mentions a 5th type.

关于UUID类型和变体的更多信息，维基百科中有一个很好的总结，RFC 4122和其他规范中有详细的信息。

看看与Java 5及更高版本捆绑在一起的UUID类。

例如:

如果你想要一个随机的UUID，你可以使用randomUUID方法。 如果您希望将UUID初始化为特定的值，可以使用UUID构造函数或fromString方法。

java.util.UUID.randomUUID（）;

在许多情况下，我们需要对象的全局UUID，特别是在事件驱动架构或事件源中，我们必须根据日期对事件进行排序，但我们不需要关于时间戳的完整信息。

在那里，我们可以使用ULID的一个实现，它是按字典顺序排序的。

格式与标准UUID不同，但仍然很简单:

example value: 01AN4Z07BY79KA1307SR9X4MV3

 01AN4Z07BY      79KA1307SR9X4MV3

|----------|    |----------------|
 Timestamp          Randomness
   48bits             80bits

在许多语言中都有实现。

例如，在Java中，有一个简单的库。

代码示例:

import de.huxhorn.sulky.ulid.ULID;

ULID ulid = new ULID();

// with current timestamp
String newId = ulid.nextULID(); 

// with selected timestamp
String newId2 = ulid.nextULID(Instant
    .parse("2021-12-01T00:00:00.00Z")
    .toEpochMilli()
); 

使用Spring，您还可以为ULID生成器创建Bean。

@Configuration
public class UUIDGeneratorConfig {

    @Bean
    public ULID ulidGenerator() {
        return new ULID();
    }
}

@Component
public class ULIDGenerator {

    private final ULID ulid;

    public ULIDGenerator(ULID ulid) {
        this.ulid = ulid;
    }

    public String generateUUID() {
        return ulid.nextULID();
    }

    public String generateUUID(Instant timestamp) {
        return ulid.nextULID(timestamp.toEpochMilli());
    }
}

其他答案都是正确的，尤其是斯蒂芬·C的这个答案。

走出Java

出于安全考虑，在Java中生成UUID值仅限于版本4(随机)。

如果你想要其他版本的uuid，一种方法是让你的Java应用程序通过调用JVM之外的方法来生成uuid:

Command-line utilityBundled with nearly every operating system. For example, uuidgen found in Mac OS X, BSD, and Linux. Database serverUse JDBC to retrieve a UUID generated on the database server.For example, the uuid-ossp extension often bundled with Postgres. That extension can generates Versions 1, 3, and 4 values and additionally a couple variations: uuid_generate_v1mc() – generates a version 1 UUID but uses a random multicast MAC address instead of the real MAC address of the computer. uuid_generate_v5(namespace uuid, name text) – generates a version 5 UUID, which works like a version 3 UUID except that SHA-1 is used as a hashing method. Web ServiceFor example, UUID Generator creates Versions 1 & 3 as well as nil values and GUID.

这取决于你想要什么样的UUID。

The standard Java UUID class generates Version 4 (random) UUIDs. (UPDATE - Version 3 (name) UUIDs can also be generated.) It can also handle other variants, though it cannot generate them. (In this case, "handle" means construct UUID instances from long, byte[] or String representations, and provide some appropriate accessors.) The Java UUID Generator (JUG) implementation purports to support "all 3 'official' types of UUID as defined by RFC-4122" ... though the RFC actually defines 4 types and mentions a 5th type.

关于UUID类型和变体的更多信息，维基百科中有一个很好的总结，RFC 4122和其他规范中有详细的信息。