优化目录结构

backend/src/main/java/com/openisle/model/Post.java

@@ -0,0 +1,65 @@
+package com.openisle.model;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.hibernate.annotations.CreationTimestamp;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import com.openisle.model.Tag;
+
+
+import java.time.LocalDateTime;
+
+/**
+ * Post entity representing an article posted by a user.
+ */
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@Table(name = "posts")
+public class Post {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false)
+    private String title;
+
+    @Column(nullable = false, columnDefinition = "TEXT")
+    private String content;
+
+    @CreationTimestamp
+    @Column(nullable = false, updatable = false,
+            columnDefinition = "DATETIME(6) DEFAULT CURRENT_TIMESTAMP(6)")
+    private LocalDateTime createdAt;
+
+    @ManyToOne(optional = false, fetch = FetchType.LAZY)
+    @JoinColumn(name = "author_id")
+    private User author;
+
+    @ManyToOne(optional = false, fetch = FetchType.LAZY)
+    @JoinColumn(name = "category_id")
+    private Category category;
+
+    @ManyToMany(fetch = FetchType.LAZY)
+    @JoinTable(name = "post_tags",
+            joinColumns = @JoinColumn(name = "post_id"),
+            inverseJoinColumns = @JoinColumn(name = "tag_id"))
+    private java.util.Set<Tag> tags = new java.util.HashSet<>();
+
+    @Column(nullable = false)
+    private long views = 0;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private PostStatus status = PostStatus.PUBLISHED;
+
+    @Column
+    private LocalDateTime pinnedAt;
+
+}