在Spring Boot框架下的web评论系统,实体有评论、子评论、用户和回复,实现检索、分页和排序功能。实体类已经完成
时间: 2023-06-18 22:08:30 浏览: 113
好的,那接下来可以考虑实现具体的功能了。首先,我们需要在Spring Boot中配置JPA,以便操作数据库。
1. 配置JPA
在`application.properties`文件中添加以下配置:
```
spring.datasource.url=jdbc:mysql://localhost:3306/comment_system?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=update
```
其中,`spring.datasource.url`是数据库连接地址,`spring.datasource.username`和`spring.datasource.password`是数据库用户名和密码。`spring.jpa.show-sql`配置为true时,可以在控制台输出执行的SQL语句,便于调试。`spring.jpa.hibernate.ddl-auto`配置为update时,可以自动创建表结构。
2. 定义实体类
根据需求,我们需要定义`Comment`、`SubComment`、`User`和`Reply`四个实体类。可以使用JPA提供的注解来定义实体类的属性和关系。例如:
```
@Entity
public class Comment {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String content;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id")
private User user;
@OneToMany(mappedBy = "comment", cascade = CascadeType.ALL, orphanRemoval = true)
private List<SubComment> subComments = new ArrayList<>();
// getters and setters
}
@Entity
public class SubComment {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String content;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "comment_id")
private Comment comment;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id")
private User user;
@OneToMany(mappedBy = "subComment", cascade = CascadeType.ALL, orphanRemoval = true)
private List<Reply> replies = new ArrayList<>();
// getters and setters
}
@Entity
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String name;
// getters and setters
}
@Entity
public class Reply {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String content;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "sub_comment_id")
private SubComment subComment;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id")
private User user;
// getters and setters
}
```
3. 编写Repository
在Spring Boot中,可以使用JpaRepository来完成常见的数据库操作。例如:
```
@Repository
public interface CommentRepository extends JpaRepository<Comment, Long> {
List<Comment> findByContentContaining(String keyword, Pageable pageable);
}
```
这里定义了一个`CommentRepository`接口,继承自`JpaRepository<Comment, Long>`,其中`Comment`是实体类,`Long`是主键类型。`findByContentContaining`方法可以根据关键词检索评论内容,同时支持分页和排序。
4. 编写Service
Service层通常用于业务逻辑的处理,可以在这里完成Repository的调用以及其他复杂业务的处理。例如:
```
@Service
public class CommentService {
@Autowired
private CommentRepository commentRepository;
public List<Comment> searchComments(String keyword, Integer pageNum, Integer pageSize, String sortField, String sortOrder) {
Sort sort = Sort.by(Sort.Direction.fromString(sortOrder), sortField);
PageRequest pageRequest = PageRequest.of(pageNum, pageSize, sort);
return commentRepository.findByContentContaining(keyword, pageRequest);
}
}
```
这里定义了一个`CommentService`类,注入了`CommentRepository`。`searchComments`方法接收关键词、页码、每页数量、排序字段和排序方式,返回符合条件的评论列表。
5. 编写Controller
Controller层通常用于接收HTTP请求,并将请求转发给Service层处理。例如:
```
@RestController
@RequestMapping("/comments")
public class CommentController {
@Autowired
private CommentService commentService;
@GetMapping
public List<Comment> searchComments(@RequestParam String keyword,
@RequestParam(required = false, defaultValue = "0") Integer pageNum,
@RequestParam(required = false, defaultValue = "10") Integer pageSize,
@RequestParam(required = false, defaultValue = "id") String sortField,
@RequestParam(required = false, defaultValue = "ASC") String sortOrder) {
return commentService.searchComments(keyword, pageNum, pageSize, sortField, sortOrder);
}
}
```
这里定义了一个`CommentController`类,映射了`/comments`路径,并注入了`CommentService`。`searchComments`方法接收请求参数,并调用Service层处理,返回符合条件的评论列表。
至此,一个简单的web评论系统就完成了。可以使用Postman等工具测试接口,检查是否符合预期。