444 lines
12 KiB
Markdown
444 lines
12 KiB
Markdown
## 任务名称: 发布动态
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### 目标:
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- 掌握实体类的设计和实现
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- 了解并发控制策略，重点掌握乐观锁的实现
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### 预备知识:
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- [JPA关联关系](../guides/JPA实体类的关联关系.md)
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- [并发控制策略](../guides/并发控制策略.md)
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### 操作步骤
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#### 1. 写发布动态接口的API文档
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- [发布动态](../api%20doc/发布动态.md)
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- [根据id获取动态详情](../api%20doc/根据id获取动态详情.md)
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#### 2. 完成实体类设计
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根据接口文档，以及前端界面的设计，完成实体类设计.
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**示例代码只包括重点的部分，其他部分可以参考项目的源码。**
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**Post**
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```java
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@Comment("冒泡/动态/文章")
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@Entity
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public class Post extends BaseAuditingEntity{
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@Version
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private Long version;
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@Comment("用户ID")
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@ManyToOne(fetch = FetchType.LAZY)
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@JoinColumn(name = "user_id")
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private User user;
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@OneToMany(mappedBy = "post", cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
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private List<PostContent> contents;
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@Comment("评论数")
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@ColumnDefault("0")
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@Column(name = "comment_count", nullable = false)
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private Long commentCount = 0L;
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@Comment("收藏数")
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@ColumnDefault("0")
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@Column(name = "collection_count", nullable = false)
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private Long collectionCount = 0L;
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@Comment("点赞数")
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@ColumnDefault("0")
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@Column(name = "upvote_count", nullable = false)
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private Long upvoteCount = 0L;
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@Comment("分享数")
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@ColumnDefault("0")
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@Column(name = "share_count", nullable = false)
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private Long shareCount = 0L;
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@Comment("可见性: 0私密 10充电可见 20订阅可见 30保留 40保留 50好友可见 60关注可见 70保留 80保留 90公开")
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@ColumnDefault("50")
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@Column(name = "visibility", nullable = false)
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private Byte visibility;
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@Comment("是否置顶")
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@ColumnDefault("0")
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@Column(name = "is_top", nullable = false)
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private Boolean isTop = false;
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@Comment("是否精华")
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@ColumnDefault("0")
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@Column(name = "is_essence", nullable = false)
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private Boolean isEssence = false;
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@Comment("是否锁定")
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@ColumnDefault("0")
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@Column(name = "is_lock", nullable = false)
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private Boolean isLock = false;
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@Comment("参与的主题")
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@Column(name = "tags")
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private String tags;
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@Comment("IP地址")
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@Column(name = "ip", length = 15)
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private String ip;
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@Comment("IP城市地址")
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@Column(name = "ip_loc", length = 64)
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private String ipLoc;
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}
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```
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**PostContent**
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```java
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@Comment("冒泡/动态/文章内容")
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@Entity
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public class PostContent extends BaseAuditingEntity{
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@Comment("冒泡/动态/文章ID")
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@ManyToOne(fetch = FetchType.LAZY)
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@JoinColumn(name = "post_id", nullable = false)
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private Post post;
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@Comment("用户ID")
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@ManyToOne(fetch = FetchType.LAZY)
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@JoinColumn(name = "user_id", nullable = false)
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private User user;
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@Comment("内容")
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@Column(name = "content", nullable = false, length = 4000)
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private String content;
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@Comment("类型，1标题，2文字段落，3图片地址，4视频地址，5语音地址，6链接地址，7附件资源，8收费资源")
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@ColumnDefault("2")
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@Column(name = "type", nullable = false)
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private Byte type = 2;
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@Comment("排序，越小越靠前")
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@ColumnDefault("100")
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@Column(name = "sort", nullable = false)
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private Integer sort =100;
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}
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```
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**Tag**
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```java
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@Comment("标签")
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@Entity
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public class Tag extends BaseAuditingEntity{
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@Version
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private Long version;
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@Comment("创建者ID")
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@ManyToOne(fetch = FetchType.LAZY)
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@JoinColumn(name = "user_id", nullable = false)
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private User user;
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@Comment("标签名")
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@Column(name = "tag", nullable = false)
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private String tag;
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@Comment("引用数")
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@ColumnDefault("0")
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@Column(name = "quote_num", nullable = false)
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private Long quoteNum = 0L;
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}
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```
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#### 3. 为每个实体类创建其对应的JpaRepository接口
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**PostRepository**
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```java
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public interface PostRepository extends JpaRepository<Post, Long> {
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}
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```
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**PostContentRepository**
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```java
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public interface PostContentRepository extends JpaRepository<PostContent, Long> {
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}
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```
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**TagRepository**
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```java
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public interface TagRepository extends JpaRepository<Tag, Long> {
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@Query("SELECT t.tag FROM Tag t WHERE t.tag LIKE CONCAT('%', :key, '%') ORDER BY t.quoteNum DESC limit 20")
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List<String> findByTagContainingOrderByQuoteNumDesc(@Param("key") String key);
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Optional<Tag> findByTag(String tag);
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}
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```
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#### 4. 完成ResponseBody的DTO类的设计
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**PostDto**
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```java
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@Value
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public class PostDto implements Serializable {
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Long id;
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Long userId;
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Long commentCount;
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Long collectionCount;
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Long upvoteCount;
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Long shareCount;
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Byte visibility;
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Boolean isTop;
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Boolean isEssence;
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Boolean isLock;
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Long latestRepliedOn;
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String tags;
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Long attachmentPrice;
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String ip;
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String ipLoc;
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@JsonSerialize(using = MillisecondToSecondSerializer.class)
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Long createdOn;
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@JsonSerialize(using = MillisecondToSecondSerializer.class)
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Long modifiedOn;
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Long deletedOn;
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Byte isDel;
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UserDto user;
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List<PostContentDto> contents;
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}
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```
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**PostContentDto**
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```java
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@Value
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public class PostContentDto implements Serializable {
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Long id;
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Long postId;
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String content;
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Byte type;
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Integer sort;
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@JsonSerialize(using = MillisecondToSecondSerializer.class)
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Long createdOn;
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@JsonSerialize(using = MillisecondToSecondSerializer.class)
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Long modifiedOn;
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}
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```
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**TagDto**
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```java
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@Value
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public class TagDto implements Serializable {
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Long id;
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Long userId;
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UserDto user;
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String tag;
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Long quoteNum;
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Long createdOn;
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Long modifiedOn;
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}
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```
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#### 5. 完成RequestBody的DTO类的设计
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**PostRequest**
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```java
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@Setter
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@Getter
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public class PostRequest {
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private Long attachmentPrice;
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private Byte visibility;
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//帖子内容列表
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List<ContentInPostRequest> contents;
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// #标签列表
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List<String> tags;
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// @用户列表
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List<String> users;
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}
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```
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**ContentInPostRequest**
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```java
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@Setter
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@Getter
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public class ContentInPostRequest {
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private String content;
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private Integer sort;
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private Byte type;
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}
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```
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#### 6. 完成MapStruct的Mapper接口
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**PostMapper**
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```java
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@Mapper(unmappedTargetPolicy = ReportingPolicy.IGNORE, componentModel = MappingConstants.ComponentModel.SPRING)
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public interface PostMapper {
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Post toEntity(PostDto postDto);
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PostDto toDto(Post post);
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@BeanMapping(nullValuePropertyMappingStrategy = NullValuePropertyMappingStrategy.IGNORE)
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Post partialUpdate(PostDto postDto, @MappingTarget Post post);
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}
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```
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**PostContentMapper**
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```java
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@Mapper(unmappedTargetPolicy = ReportingPolicy.IGNORE, componentModel = MappingConstants.ComponentModel.SPRING)
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public interface PostContentMapper {
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PostContent toEntity(PostContentDto postContentDto);
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PostContentDto toDto(PostContent postContent);
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@BeanMapping(nullValuePropertyMappingStrategy = NullValuePropertyMappingStrategy.IGNORE)
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PostContent partialUpdate(PostContentDto postContentDto, @MappingTarget PostContent postContent);
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}
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```
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**TagMapper**
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```java
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@Mapper(unmappedTargetPolicy = ReportingPolicy.IGNORE, componentModel = MappingConstants.ComponentModel.SPRING)
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public interface TagMapper {
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Tag toEntity(TagDto tagDto);
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@Mapping(source = "user.id", target = "userId")
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@Mapping(source = "user", target = "user")
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TagDto toDto(Tag tag);
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@BeanMapping(nullValuePropertyMappingStrategy = NullValuePropertyMappingStrategy.IGNORE)
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Tag partialUpdate(TagDto tagDto, @MappingTarget Tag tag);
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}
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```
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#### 7. 完成PostService中发布动态的实现
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创建PostService类，实现createPost方法。
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```java
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/**
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* 处理文章发布请求
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* @param postRequest 创建文章的请求参数
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* @return 创建成功后的文章DTO
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*/
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public PostDto handlePostRequest(PostRequest postRequest){
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// 获取当前用户
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User user = authService.getCurrentUser();
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// 保存文章
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Post post = savePost(postRequest, user);
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// 处理post中的标签
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handleTags(postRequest, user);
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// 发送消息通知post中@的用户
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handleAtUser(postRequest, user);
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return postMapper.toDto(post);
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}
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private Post savePost(PostRequest postRequest, User currentUser){
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Post post = new Post();
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post.setUser(currentUser);
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// 设置附件价格，默认为0
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post.setAttachmentPrice(postRequest.getAttachmentPrice()!=null?postRequest.getAttachmentPrice():0);
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// 设置文章可见性
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post.setVisibility(postRequest.getVisibility());
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// 文章内容
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List<PostContent> contents = new ArrayList<>();
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postRequest.getContents().forEach(contentReq -> {
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PostContent content = new PostContent();
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content.setContent(contentReq.getContent()); // 设置内容
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content.setSort(contentReq.getSort()); // 设置排序
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content.setType(contentReq.getType()); // 设置类型
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content.setPost(post); // 关联文章
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content.setUser(currentUser); // 关联用户
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contents.add(content); // 添加到列表
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});
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post.setContents(contents);
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// 保存文章
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return postRepository.save(post);
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}
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private void handleTags(PostRequest postRequest, User currentUser){
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// 处理post中的标签
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postRequest.getTags().forEach((tag)->{
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Tag tagEntity = tagRepository.findByTag(tag).orElse(null);
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if(tagEntity==null){
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// 如果标签不存在，则创建新标签并关联文章
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tagEntity = new Tag();
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tagEntity.setTag(tag);
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tagEntity.setUser(currentUser);
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tagEntity.setQuoteNum(1L);
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tagRepository.save(tagEntity);
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}else{
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// 如果标签已存在，则更新引用次数
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try {
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tagEntity.setQuoteNum(tagEntity.getQuoteNum() + 1L);
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tagRepository.save(tagEntity); // Spring Data JPA 自动处理乐观锁
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} catch (OptimisticLockingFailureException e) {
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// 处理乐观锁失败的情况，如重新获取实体并重试或记录日志等
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log.error("Optimistic locking failed for tag: {}", tagEntity.getTag(), e);
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// TODO： 可添加重试逻辑
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// 简单处理为继续抛出异常，让此次发帖失败
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throw e;
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}
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}
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});
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}
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private void handleAtUser(PostRequest postRequest, User currentUser){
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postRequest.getUsers().forEach((username)->{
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User toUser = userRepository.findByUsername(username).orElseThrow(()->new ResourceNotFoundException("User","username="+username));
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// TODO: 发送消息通知toUser
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});
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}
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```
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#### 8. 完成PostController中发布动态的实现
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创建PostController类，实现createPost方法。
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```java
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@PostMapping("/post")
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public DataResult<PostDto> createPost(@RequestBody PostRequest postRequest) {
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return ResultUtil.ok(postService.createPost(postRequest));
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}
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```
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#### 9. 实现根据id获取动态功能
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在PostService类中添加getPost方法。
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```java
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/**
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* 根据文章ID获取文章详情
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* @param id 文章ID
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* @return 文章DTO
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*/
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public PostDto getPost(Long id){
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Post post = postRepository.findById(id).orElseThrow(()->new ResourceNotFoundException("Post","id="+id));
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return postMapper.toDto(post);
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}
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```
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在PostController类中添加getPost方法。
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```java
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@GetMapping("/post")
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public DataResult<PostDto> getPost(@PathParam("id") Long id) {
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return ResultUtil.ok(postService.getPost(id));
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}
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```
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#### 10. 通过前端完成发布动态
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- 运行vue前端项目
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- 在浏览器中访问http://localhost:5173
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- 登录账号
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- 完成发布动态: 上传图片、内容中支持#主题
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### 技术/工具需求:
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- [ip2region](https://github.com/lionsoul2014/ip2region) 根据ip地址获取用户所在地
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### 成功标准:
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- 通过paopao ce的vue前端完成发布动态功能
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### 扩展学习(可选):
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- [提供一些额外学习资源或挑战性任务，鼓励学有余力的学生进一步探索。]
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### 评估与反馈:
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- [说明如何提交作业、代码审查的标准、或任何反馈收集机制。]
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### 时间估算:
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- 4 Hours |