feat: RankingKey 클래스 추가 및 Redis ZSET 키 생성 유틸리티 구현

Author: rnqhstmd

apps/commerce-api/src/main/java/com/loopers/domain/ranking/RankingKey.java

@@ -0,0 +1,32 @@
+package com.loopers.domain.ranking;
+
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+
+/**
+ * Redis ZSET 키 생성 유틸리티
+ */
+public class RankingKey {
+
+    private static final String KEY_PREFIX = "ranking:all:";
+    private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("yyyyMMdd");
+
+    private RankingKey() {
+    }
+
+    public static String daily(LocalDate date) {
+        return KEY_PREFIX + date.format(DATE_FORMATTER);
+    }
+
+    public static String today() {
+        return daily(LocalDate.now());
+    }
+
+    public static String fromDateString(String dateString) {
+        return KEY_PREFIX + dateString;
+    }
+
+    public static LocalDate parseDate(String dateString) {
+        return LocalDate.parse(dateString, DATE_FORMATTER);
+    }
+}