SpringBoot2.x系列教程40--SpringBoot中默认的缓存实现方案

packagecom.yyg.boot.config;
importorg.springframework.cache.annotation.EnableCaching;
/*** @Author 一一哥Sun* @Date Created in 2020/4/14* @Description Description* EnableCaching启用缓存*/@Configuration@EnableCachingpublicclassCacheConfig {
}

packagecom.yyg.boot.domain;
importlombok.Data;
importlombok.ToString;
importjavax.persistence.*;
importjava.io.Serializable;
@Entity@Table(name="user")
@Data@ToStringpublicclassUserimplementsSerializable {
//IllegalArgumentException: DefaultSerializer requires a Serializable payload// but received an object of type [com.syc.redis.domain.User]@Id@GeneratedValue(strategy=GenerationType.AUTO)
privateLongid;
@ColumnprivateStringusername;
@ColumnprivateStringpassword;
}

packagecom.yyg.boot.repository;
importcom.yyg.boot.domain.User;
importorg.springframework.data.jpa.repository.JpaRepository;
publicinterfaceUserRepositoryextendsJpaRepository<User,Long> {
}

packagecom.yyg.boot.service;
importcom.yyg.boot.domain.User;
publicinterfaceUserService {
UserfindById(Longid);
Usersave(Useruser);
voiddeleteById(Longid);
}

packagecom.yyg.boot.service.impl;
importcom.yyg.boot.domain.User;
importcom.yyg.boot.repository.UserRepository;
importcom.yyg.boot.service.UserService;
importorg.springframework.beans.factory.annotation.Autowired;
importorg.springframework.cache.annotation.CacheEvict;
importorg.springframework.cache.annotation.CachePut;
importorg.springframework.cache.annotation.Cacheable;
importorg.springframework.stereotype.Service;
@ServicepublicclassUserServiceImplimplementsUserService {
@AutowiredprivateUserRepositoryuserRepository;
//普通的缓存+数据库查询代码实现逻辑://User user=RedisUtil.get(key);//   if(user==null){//      user=userDao.findById(id);//      //redis的key="product_item_"+id//      RedisUtil.set(key,user);//   }//   return user;/***  注解@Cacheable:查询的时候才使用该注解!*  注意:在Cacheable注解中支持EL表达式*  redis缓存的key=user_1/2/3....*  redis的缓存雪崩,缓存穿透,缓存预热,缓存更新...*  condition = "#result ne null",条件表达式,当满足某个条件的时候才进行缓存*  unless = "#result eq null":当user对象为空的时候,不进行缓存*/@Cacheable(value="user", key="#id", unless="#result eq null")
@OverridepublicUserfindById(Longid) {
returnuserRepository.findById(id).orElse(null);
    }
/*** 注解@CachePut:一般用在添加和修改方法中* 既往数据库中添加一个新的对象,于此同时也往redis缓存中添加一个对应的缓存.* 这样可以达到缓存预热的目的.*/@CachePut(value="user", key="#result.id", unless="#result eq null")
@OverridepublicUsersave(Useruser) {
returnuserRepository.save(user);
    }
/*** CacheEvict:一般用在删除方法中*/@CacheEvict(value="user", key="#id")
@OverridepublicvoiddeleteById(Longid) {
userRepository.deleteById(id);
    }
}

packagecom.yyg.boot.web;
importcom.yyg.boot.domain.User;
importcom.yyg.boot.service.UserService;
importlombok.extern.slf4j.Slf4j;
importorg.springframework.beans.factory.annotation.Autowired;
importorg.springframework.http.HttpStatus;
importorg.springframework.http.ResponseEntity;
importorg.springframework.web.bind.annotation.*;
@RestController@RequestMapping("/user")
@Slf4jpublicclassUserController {
@AutowiredprivateUserServiceuserService;
@PostMappingpublicUsersaveUser(@RequestBodyUseruser) {
returnuserService.save(user);
    }
@GetMapping("/{id}")
publicResponseEntity<User>getUserById(@PathVariable("id") Longid) {
Useruser=userService.findById(id);
log.warn("user="+user.hashCode());
HttpStatusstatus=user==null?HttpStatus.NOT_FOUND : HttpStatus.OK;
returnnewResponseEntity<>(user, status);
    }
@DeleteMapping("/{id}")
publicStringremoveUser(@PathVariable("id") Longid) {
userService.deleteById(id);
return"ok";
    }
}

packagecom.yyg.boot;
importorg.springframework.boot.SpringApplication;
importorg.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplicationpublicclassCacheApplication {
publicstaticvoidmain(String[] args) {
SpringApplication.run(CacheApplication.class, args);
    }
}