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动手试一试 Spring Boot默认缓存管理

news 2025/5/24 6:54:01

1.准备数据

使用之前创建的springbootdata的数据库，该数据库有两个表t_article和t_comment，这两个表预先插入几条测试数据。

2.编写数据库表对应的实体类

@Entity(name = "t_comment")
public class Comment {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Integer id;private String content;private String author;@Column(name = "a_id")private Integer aId;//补充get set toString}

3.创建CommentRepository

public interface CommentRepository extends JpaRepository<Comment,Integer>{@Transactional@Modifying@Query("UPDATE t_comment c SET c.author= ?1 WHERE  c.id = ?2")public int updateComment(String author,Integer id);}

4.创建CommentService

在该类中编写数据的查询、修改和删除操作

@Service
public class CommentService {@Autowiredprivate CommentRepository commentRepository;public Comment findById(int comment_id){Optional<Comment> optional = commentRepository.findById(comment_id);if(optional.isPresent()){return optional.get();}return null;}public Comment updateComment(Comment comment){commentRepository.updateComment(comment.getAuthor(), comment.getId());return comment;}public void deleteComment(int comment_id){commentRepository.deleteById(comment_id);}
}

5.创建CommentController

使用注入的CommentService实例对象编写对Comment评论数据的查询、修改和删除方法。

@RestController
public class CommentController {@Autowiredprivate CommentService commentService;@GetMapping("/get/{id}")public Comment findById(@PathVariable("id") int comment_id) {Comment comment = commentService.findById(comment_id);return comment;}@GetMapping("/update/{id}/{author}")public Comment updateComment(@PathVariable("id") int comment_id, @PathVariable("author") String author) {Comment comment = commentService.findById(comment_id);comment.setAuthor(author);Comment updateComment = commentService.updateComment(comment);return updateComment;}@GetMapping("/delete/{id}")public void deleteComment(@PathVariable("id") int comment_id) {commentService.deleteComment(comment_id);}
}

6.设置配置信息

spring.datasource.url=jdbc:mysql://localhost:3306/springbootdata?serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root
spring.jpa.show-sql=true

7.项目测试

项目启动成功后，在浏览器上访问http://localhost:8080/get/1，浏览器每刷新一次，控制台会新输出一条SQL语句

每执行一次查询操作，都会访问一次数据库并执行一次SQL语句。

8、启动类上添加@EnableCaching注解

开启基于注解的缓存支持

//启动类
@EnableCaching
@SpringBootApplication
public class Chapter06Application {public static void main(String[] args) {SpringApplication.run(Chapter06Application.class, args);}
}

9、使用@Cacheable注解对数据操作方法进行缓存管理

//业务层
@Cacheable(cacheNames = "comment")
public Comment findById(int comment_id){Optional<Comment> optional = commentRepository.findById(comment_id);if(optional.isPresent()){return optional.get();}return null;
}