如何在java中将Base64编码的字符串转换为UUID

Question

this is the encoded string

YjRmYTJhMGEtYjI0ZC00ZjU4LTg2ZDktNTNiN2I2ODM4YjY3IzU1YjFjNGUzZTRiMGQ4OTUxMGM2YWEyNw

i want to generate UUID for this

Answer 1

You can convert as below using 2 functions. apache commons codec jar has some methods to encode and decode UUID using Base64 .

Link to download apache commons codec jar: http://www.java2s.com/Code/JarDownload/apache-commons/apache-commons-codec-1.4.jar.zip

import java.nio.ByteBuffer;
import java.util.UUID;

import org.apache.commons.codec.binary.Base64;


public class Solution1 {
    public static void main(String[] args) {
        String uuid_str = "YjRmYTJhMGEtYjI0ZC00ZjU4LTg2ZDktNTNiN2I2ODM4YjY3IzU1YjFjNGUzZTRiMGQ4OTUxMGM2YWEyNw";
        String uuid_as_64 = uuidFromBase64(uuid_str);
        System.out.println("as base64: "+uuid_as_64);
        System.out.println("as uuid: "+uuidFromBase64(uuid_as_64));
    }

    private static String uuidToBase64(String str) {
        Base64 base64 = new Base64();
        UUID uuid = UUID.fromString(str);
        ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
        bb.putLong(uuid.getMostSignificantBits());
        bb.putLong(uuid.getLeastSignificantBits());
        return base64.encodeBase64URLSafeString(bb.array());
    }
    private static String uuidFromBase64(String str) {
        Base64 base64 = new Base64(); 
        byte[] bytes = base64.decodeBase64(str);
        ByteBuffer bb = ByteBuffer.wrap(bytes);
        UUID uuid = new UUID(bb.getLong(), bb.getLong());
        return uuid.toString();
    }
}

Output:

as base64: 62346661-3261-3061-2d62-3234642d3466

as uuid: eb6df8eb-aeb5-fb7d-bad7-edf4eb5fb677

For more, you can follow the tutorial:

1. http://www.baeldung.com/java-base64-encode-and-decode
2. http://www.tutorialspoint.com/java8/java8_base64.htm
3. How can I convert a UUID to base64?
4. Storing UUID as base64 String

Answer 2

The above base64 string decodes to ASCII string "b4fa2a0a-b24d-4f58-86d9-53b7b6838b67#55b1c4e3e4b0d89510c6aa27", so:

import org.apache.commons.codec.binary.Base64;
public class Solution {
    private static String uuidFromBase64(String str) {
        Base64 base64 = new Base64(); 
        byte[] bytes = base64.decodeBase64(str);
        String s = new String(bytes);
        String trimmed = s.split("#")[0];
        return trimmed;
    }
}