search
HomeJavajavaTutorialWhat is UUID? How to generate UUID in Java

What this article brings to you is about what is UUID? The method of generating UUID in Java has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

UUID introduction:

UUID (Universally Unique Identifier) ​​globally unique identifier refers to a number generated on one machine, which is guaranteed to be unique to all machines in the same time and space. Calculations based on standards set by the Open Software Foundation (OSF) use the Ethernet card address, nanosecond time, chip ID and many possible numbers. It is a combination of the following parts: the current date and time (the first part of the UUID is related to the time, if you generate a UUID after a few seconds, the first part is different and the rest are the same), clock Sequence, a globally unique IEEE machine identification number (if there is a network card, it is obtained from the network card, if there is no network card, it is obtained in other ways). The only flaw of UUID is that the generated result string will be relatively long.

UUID function:

We usually use int as the primary key of the database, which can be easily used for auto-increment, but the data range of using int is limited. If there is a large amount of data, the value range of int may be exceeded. So we can use uuid as primary key.

The details of their advantages and disadvantages can be found online

The class java.Util.UUID in java

(It is best to generate the UUID in the java program and then put the data Insert into the database, there is no need to modify the code that generates UUID if you change the database)

jdk1.5 adds the class java.Util.UUID to facilitate the generation of UUID.

Code:

/**
 * @author hh
 * @Date 2018/9/12 */public class UUIDUtil {    
 /**
     * 获取UUID 32位
     * @return
     */
    public static String createUUID(){
        String uuid= UUID.randomUUID().toString();        
        return  uuid.replace("-","");
    }
}

Run:

What is UUID? How to generate UUID in Java

The storage type of UUID in the database

Take mySql database as an example

select replace(uuid(),'-','') from dual;

Run:

What is UUID? How to generate UUID in Java

##Related recommendations:

Generate UUID in PHP, PHP generates UUID

Mysql operation to generate UUID_MySQL

The above is the detailed content of What is UUID? How to generate UUID in Java. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How do I use Maven or Gradle for advanced Java project management, build automation, and dependency resolution?How do I use Maven or Gradle for advanced Java project management, build automation, and dependency resolution?Mar 17, 2025 pm 05:46 PM

The article discusses using Maven and Gradle for Java project management, build automation, and dependency resolution, comparing their approaches and optimization strategies.

How do I create and use custom Java libraries (JAR files) with proper versioning and dependency management?How do I create and use custom Java libraries (JAR files) with proper versioning and dependency management?Mar 17, 2025 pm 05:45 PM

The article discusses creating and using custom Java libraries (JAR files) with proper versioning and dependency management, using tools like Maven and Gradle.

How do I implement multi-level caching in Java applications using libraries like Caffeine or Guava Cache?How do I implement multi-level caching in Java applications using libraries like Caffeine or Guava Cache?Mar 17, 2025 pm 05:44 PM

The article discusses implementing multi-level caching in Java using Caffeine and Guava Cache to enhance application performance. It covers setup, integration, and performance benefits, along with configuration and eviction policy management best pra

How can I use JPA (Java Persistence API) for object-relational mapping with advanced features like caching and lazy loading?How can I use JPA (Java Persistence API) for object-relational mapping with advanced features like caching and lazy loading?Mar 17, 2025 pm 05:43 PM

The article discusses using JPA for object-relational mapping with advanced features like caching and lazy loading. It covers setup, entity mapping, and best practices for optimizing performance while highlighting potential pitfalls.[159 characters]

How does Java's classloading mechanism work, including different classloaders and their delegation models?How does Java's classloading mechanism work, including different classloaders and their delegation models?Mar 17, 2025 pm 05:35 PM

Java's classloading involves loading, linking, and initializing classes using a hierarchical system with Bootstrap, Extension, and Application classloaders. The parent delegation model ensures core classes are loaded first, affecting custom class loa

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Best Graphic Settings
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. How to Fix Audio if You Can't Hear Anyone
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
R.E.P.O. Chat Commands and How to Use Them
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor