一、什么是NanoId
nanoid库和uuid库一样都可以生成唯一识别码 ，但是nanoid相比uuid要更轻量级。
二、怎么使用
引入jar包或使用工具类
<dependency> <groupId>com.aventrix.jnanoid</groupId> <artifactId>jnanoid</artifactId> <version>2.0.0</version> </dependency>
工具类
import java.security.SecureRandom; import java.util.Random; public final class NanoIdUtils { public static final SecureRandom DEFAULT_NUMBER_GENERATOR = new SecureRandom(); public static final char[] DEFAULT_ALPHABET = "_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray(); public static final int DEFAULT_SIZE = 21; private NanoIdUtils() { } public static String randomNanoId() { return randomNanoId(DEFAULT_NUMBER_GENERATOR, DEFAULT_ALPHABET, 21); } public static String randomNanoId(Random random, char[] alphabet, int size) { if (random == null) { throw new IllegalArgumentException("random cannot be null."); } else if (alphabet == null) { throw new IllegalArgumentException("alphabet cannot be null."); } else if (alphabet.length != 0 && alphabet.length < 256) { if (size <= 0) { throw new IllegalArgumentException("size must be greater than zero."); } else { int mask = (2 << (int)Math.floor(Math.log((double)(alphabet.length - 1)) / Math.log(2.0D))) - 1; int step = (int)Math.ceil(1.6D * (double)mask * (double)size / (double)alphabet.length); StringBuilder idBuilder = new StringBuilder(); while(true) { byte[] bytes = new byte[step]; random.nextBytes(bytes); for(int i = 0; i < step; ++i) { int alphabetIndex = bytes[i] & mask; if (alphabetIndex < alphabet.length) { idBuilder.append(alphabet[alphabetIndex]); if (idBuilder.length() == size) { return idBuilder.toString(); } } } } } } else { throw new IllegalArgumentException("alphabet must contain between 1 and 255 symbols."); } } }
三、初体验
public static void main(String[] args) { for (int i = 0; i < 10; i++) { System.out.println(NanoIdUtils.randomNanoId()); System.out.println(UUID.randomUUID()); } }
DHxVDk6OlUpJv4DMsJBQm f6a4834d-494d-411f-98c6-aae886d104ec OITlZuemCDn9CRR0ZruMB 0990b182-127a-44f7-9660-5bf9e8fb232f GNNdtQaXVCRYgfxPbr1TF 8de0a3f9-5db1-43a9-806f-be95084586d2 BXpOVuLkOGdiu6bwxV34i c9dbfdab-11a0-454c-b700-55f3556c5335 KB8kXivS0urYqnx_Hs1vp 36775a12-bed3-47f4-b9d9-eecb156079fa nuTskLmIof63GExt9sduR b448109f-bad9-473c-a1c5-f3a65f80a698 pJRdALwVBlrVMSuKwEX_z e252312e-3806-4581-b3b4-842cccf83298 LuH50GGpZGqQz4ny2F7wT 01b846b0-753b-4fcf-97bd-c19bd2368570 qBndTEU1n2KBslPqORc67 a2f828cc-b5cf-4639-b2fe-e674ae0db4b5 vbNaVYd6rqUfbEWpcxrKM 321cc407-e72f-434f-89ce-06c6eec3ff88
四、相比优势
空间小、更安全、可以自动以子母表
