创建 IdGenerator，封装 SnowflakeId、UUID 的生成。

src/main/java/xyz/zhouxy/plusone/commons/util/IdGenerator.java

@@ -0,0 +1,61 @@
+package xyz.zhouxy.plusone.commons.util;
+
+import java.util.UUID;
+
+import com.google.common.annotations.Beta;
+import com.google.common.collect.HashBasedTable;
+import com.google.common.collect.Table;
+
+@Beta
+public class IdGenerator {
+
+    // ===== UUID =====
+
+    public static UUID newUuid() {
+        return UUID.randomUUID();
+    }
+
+    public static String uuidString() {
+        return UUID.randomUUID().toString();
+    }
+
+    public static String simpleUuidString() {
+        return toSimpleString(UUID.randomUUID());
+    }
+
+    public static String toSimpleString(UUID uuid) {
+        return (digits(uuid.getMostSignificantBits() >> 32, 8) +
+                digits(uuid.getMostSignificantBits() >> 16, 4) +
+                digits(uuid.getMostSignificantBits(), 4) +
+                digits(uuid.getLeastSignificantBits() >> 48, 4) +
+                digits(uuid.getLeastSignificantBits(), 12));
+    }
+
+    // ===== SnowflakeId =====
+
+    private static final Table<Long, Long, SnowflakeIdGenerator> snowflakePool = HashBasedTable.create();
+
+    public static long nextSnowflakeId(long workerId, long datacenterId) {
+        SnowflakeIdGenerator generator = snowflakePool.get(workerId, datacenterId);
+        if (generator == null) {
+            synchronized (IdGenerator.class) {
+                generator = snowflakePool.get(workerId, datacenterId);
+                if (generator == null) {
+                    generator = new SnowflakeIdGenerator(workerId, datacenterId);
+                    snowflakePool.put(workerId, datacenterId, generator);
+                }
+            }
+        }
+        return generator.nextId();
+    }
+
+    /** Returns val represented by the specified number of hex digits. */
+    private static String digits(long val, int digits) {
+        long hi = 1L << (digits * 4);
+        return Long.toHexString(hi | (val & (hi - 1))).substring(1);
+    }
+
+    private IdGenerator() {
+        throw new IllegalStateException("Utility class");
+    }
+}