init

2025-10-16 11:53:45 +09:00
commit c204bbf106
9 changed files with 724 additions and 0 deletions
@@ -0,0 +1,70 @@
+package com.eactive.ext.kjb.ums;
+
+import java.math.BigInteger;
+import java.nio.ByteBuffer;
+import java.util.UUID;
+
+public class UUIDBase62Util {
+    private static final String BASE62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+
+    public static String uuidStringToBase62(String uuidStr) {
+        UUID uuid = UUID.fromString(uuidStr);
+        ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
+        bb.putLong(uuid.getMostSignificantBits());
+        bb.putLong(uuid.getLeastSignificantBits());
+        BigInteger bigInt = new BigInteger(1, bb.array());
+        return toBase62(bigInt);
+    }
+
+    public static String base62ToUuidString(String base62Str) {
+        BigInteger bigInt = fromBase62(base62Str);
+        byte[] bytes = toByteArray(bigInt, 16);
+        ByteBuffer bb = ByteBuffer.wrap(bytes);
+        long msb = bb.getLong();
+        long lsb = bb.getLong();
+        return new UUID(msb, lsb).toString();
+    }
+
+    private static String toBase62(BigInteger value) {
+        StringBuilder sb = new StringBuilder();
+        while (value.compareTo(BigInteger.ZERO) > 0) {
+            BigInteger[] divRem = value.divideAndRemainder(BigInteger.valueOf(62));
+            sb.append(BASE62.charAt(divRem[1].intValue()));
+            value = divRem[0];
+        }
+        // pad to 22 chars for consistent length
+        while (sb.length() < 22) sb.append('0');
+        return sb.reverse().toString();
+    }
+
+    private static BigInteger fromBase62(String base62) {
+        BigInteger result = BigInteger.ZERO;
+        for (char c : base62.toCharArray()) {
+            int digit = BASE62.indexOf(c);
+            if (digit == -1) throw new IllegalArgumentException("Invalid Base62 character: " + c);
+            result = result.multiply(BigInteger.valueOf(62)).add(BigInteger.valueOf(digit));
+        }
+        return result;
+    }
+
+    private static byte[] toByteArray(BigInteger bigInt, int size) {
+        byte[] src = bigInt.toByteArray();
+        byte[] dst = new byte[size];
+        int srcPos = Math.max(0, src.length - size);
+        int dstPos = Math.max(0, size - src.length);
+        int length = Math.min(size, src.length);
+        System.arraycopy(src, srcPos, dst, dstPos, length);
+        return dst;
+    }
+
+    public static void main(String[] args) {
+        String uuid = UUID.randomUUID().toString();
+        String base62 = uuidStringToBase62(uuid);
+        String decoded = base62ToUuidString(base62);
+
+        System.out.println("UUID  : " + uuid);
+        System.out.println("Base62: " + base62 + " (" + base62.length() + ")");
+        System.out.println("Decoded: " + decoded);
+        System.out.println("Same? " + uuid.equals(decoded));
+    }
+}