SpringBoot Cache 入门

添加依赖

 <groupId>org.springframework.boot</groupId>

 <artifactId>spring-boot-starter-cache</artifactId>

</dependency>

2.  开始配置Cache



    a. 在启动类增加一个注解@EnableCaching@SpringBootApplication@MapperScan("com.tanoak.mapper")

@EnableCaching

public class BootCacheApplication {



 public static void main(String[] args) {

 SpringApplication.run(BootCacheApplication.class, args);

 }

} 

b.  pojo

@Data

    public class Teacher {//使用Lombok注解



     private Integer id;

     private String lastName;

     private String email;

    

     /\*\*

     \*性别 1男  0女

     \*/

     private Integer sex;

     private Integer sId;

    } 

c. Mappe

 @Mappe

    public interface TeacherMapper {

    

     @Select("SELECT \* FROM teacher WHERE id =#{id}")

     Teacher getTeaById(Integer id);

    

     @Update("UPDATE teacher SET lastName =#{lastName},email=#{email},sex=#{sex},s\_id=#{sId} WHERE id=#{id}")

     Integer update(Teacher teacher) ;

    

     @Delete("DELETE FROM teacher WHERE id =#{id}")

     Integer deleteById(Integer id) ;

    

     @Insert("INSERT INTO teacher(lastName,email,sex,t\_id) VALUES(#{lastName},#{email},#{sex},#{sId})")

     Integer insert(Teacher teacher) ;

    }

d. Service

 /\*\*

 \*  根据ID查询实体

 \* @param id

 \* @return

 \*/

 Teacher getEmpById(Integer id) ;

 Integer update(Teacher teacher) ;

 Integer remove(Integer id) ;

}

//实现类

@Service

public class TeacherServiceImpl implements TeacherService {

 private static final Logger logger = LoggerFactory.getLogger(TeacherServiceImpl.class);

 @Resource

 private TeacherMapper teacherMapper ;

 @Override

 @Cacheable(cacheNames = {"emp"},condition = "#id>0")

 public Teacher getEmpById(Integer id) {

 logger.info("进行查询实体 ID为"+id);

 return teacherMapper.getTeaById(id) ;

 }

 @Override

 public Integer update(Teacher teacher) {

 logger.info("修改的实体为"+teacher.toString());

 return teacherMapper.update(teacher) ;

 }

 @Override

 public Integer remove(Integer id) {

 logger.info("删除的实体 ID为"+id);

 return teacherMapper.deleteById(id) ;

 }

}

    e. Controlle@RestControllepublic class TeacherController {



 @Resource

 private TeacherService teacherService ;



 @GetMapping("/tea/{id}")

 @Cacheable(cacheNames = "tea")

 public Teacher getTea(@PathVariable("id")Integer id){

 return  teacherService.getEmpById(id) ;

 }

}

然后就开启缓存，本篇文章结束！开个玩笑，在正常的开发中，我们的CRUD需要进行缓存的环节一般是在查询，更新，删除，在一些特殊的业务场景下也会对插入进行缓存，这里不做考虑。然后我们根据需求想要解决这个问题，那么Cache对应的注解就出现了

#根据方法的请求参数对其结果进行缓存

    @Cacheable

    -----------

    #保证方法被调用，又希望结果被缓存。

    @CachePut

    ------------

    清空缓存

    @CacheEvict

了解这三个注解我们来看下如何使用吧

key  缓存的 key 支持SpEl表达式



keyGenerator  自定义Key生成策略  二选一（key or keyGenerator）



condition   符合指定条件缓存



unless 条件为true不缓存 

@Override

 @Cacheable(cacheNames = "tea",key = "#id",condition = "#id>1")

 public Teacher getTeaById(Integer id) {

 logger.info("进行查询实体 ID为"+id);

 return teacherMapper.getTeaById(id) ;

}



@GetMapping("/tea/{id}")

 public Teacher getTea(@PathVariable("id")Integer id){

 return  teacherService.getEmpById(id) ;

 }

public class MyKeyGenerator {



 @Bean("mykeyGenerator")

 public KeyGenerator keyGenerator(){

 return new KeyGenerator(){

 @Override

 public Object generate(Object target, Method method, Object ...params){

 return method.getName() +"{"+Arrays.asList(params) +"}";

 }

 };

 }

}

 @Cacheable(cacheNames = "tea",keyGenerator="mykeyGenerator")

 public Teacher getTeaById(Integer id) {

 logger.info("进行查询实体 ID为"+id);

 return teacherMapper.getTeaById(id) ;

 }





@GetMapping("/tea2/{id}")

 public Teacher getTea2(@PathVariable("id")Integer id){

 return  teacherService.getTeaById(id) ;

 }```



目前解决了查询的缓存，接下来处理更新的缓存



## @CachePut



这个注解是在方法执行完成后调用的与@Cacheable的调用顺序刚好相反