后端：公告√

注意数据库新建notice表

backend/src/main/java/com/example/demo/notice/NoticeStatusConverter.java

@@ -0,0 +1,30 @@
+package com.example.demo.notice;
+
+import jakarta.persistence.AttributeConverter;
+import jakarta.persistence.Converter;
+
+@Converter(autoApply = false)
+public class NoticeStatusConverter implements AttributeConverter<NoticeStatus, String> {
+    @Override
+    public String convertToDatabaseColumn(NoticeStatus attribute) {
+        if (attribute == null) return null;
+        return switch (attribute) {
+            case DRAFT -> "draft";
+            case PUBLISHED -> "published";
+            case OFFLINE -> "offline";
+        };
+    }
+
+    @Override
+    public NoticeStatus convertToEntityAttribute(String dbData) {
+        if (dbData == null) return null;
+        return switch (dbData) {
+            case "draft" -> NoticeStatus.DRAFT;
+            case "published" -> NoticeStatus.PUBLISHED;
+            case "offline" -> NoticeStatus.OFFLINE;
+            default -> NoticeStatus.PUBLISHED;
+        };
+    }
+}
+
+