feat(singer): 添加歌手收藏时间显示功能

- 在SingerDTO中新增collectTime字段用于显示收藏时间
- 修改SingerServiceImpl中的分页查询逻辑以填充收藏时间信息
- 修复UserCollectPlaylist实体中createTime字段的数据库映射注解
- 扩展UserSingerRepository添加findByUserIdAndSingerId方法支持收藏记录查询

music-houduan/src/main/java/com/test/musichouduan/dto/SingerDTO.java

@@ -70,6 +70,12 @@ public class SingerDTO {
      */
     private Boolean isCollected;
 
+    /**
+     * 收藏时间
+     */
+    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
+    private LocalDateTime collectTime;
+
     /**
      * 创建时间
      */

music-houduan/src/main/java/com/test/musichouduan/entity/UserCollectPlaylist.java

@@ -36,6 +36,6 @@ public class UserCollectPlaylist {
      * 收藏时间
      */
     @CreationTimestamp
-    @Column(nullable = false, updatable = false)
+    @Column(name = "collect_time", nullable = false, updatable = false)
     private LocalDateTime createTime;
 }

music-houduan/src/main/java/com/test/musichouduan/repository/UserSingerRepository.java

@@ -12,6 +12,8 @@ import org.springframework.data.repository.query.Param;
 import org.springframework.stereotype.Repository;
 import org.springframework.transaction.annotation.Transactional;
 
+import java.util.Optional;
+
 /**
  * 用户歌手关联数据访问层
  */
@@ -86,4 +88,13 @@ public interface UserSingerRepository extends JpaRepository<UserSinger, Long> {
     @Transactional
     @Query("DELETE FROM UserSinger us WHERE us.singer.id = :singerId")
     void deleteBySingerId(@Param("singerId") Long singerId);
+
+    /**
+     * 根据用户ID和歌手ID查询收藏记录
+     *
+     * @param userId 用户ID
+     * @param singerId 歌手ID
+     * @return 收藏记录
+     */
+    Optional<UserSinger> findByUserIdAndSingerId(Long userId, Long singerId);
 }

music-houduan/src/main/java/com/test/musichouduan/service/impl/SingerServiceImpl.java

@@ -385,9 +385,15 @@ public class SingerServiceImpl implements SingerService {
                 PageRequest.of(page - 1, size, Sort.by(Sort.Direction.DESC, "collectTime"))
         );
 
-        // 转换为DTO
+        // 转换为DTO，并填充收藏时间
         List<SingerDTO> singerDTOs = singerPage.getContent().stream()
-                .map(this::convertToDTO)
+                .map(singer -> {
+                    SingerDTO dto = convertToDTO(singer);
+                    // 从收藏记录中获取收藏时间
+                    userSingerRepository.findByUserIdAndSingerId(userId, singer.getId())
+                            .ifPresent(us -> dto.setCollectTime(us.getCollectTime()));
+                    return dto;
+                })
                 .collect(Collectors.toList());
 
         return new PageResult<>(