SpringBoot整合Caffeine本地缓存

1.导入依赖

	com.github.ben-manes.caffeine
	caffeine
	2.9.2

2.配置caffeine缓存

@Component
public class AuthBefeorCache {

    @Autowired
    private UserMapper userMapper;

    //缓存最大数量
    private final Integer MAX_SIZE = 300000;

    //缓存有效期值30
    private final Long DURATION = 30L;

    //定义及配置Caffeine本地缓存
    private LoadingCache cache = Caffeine.newBuilder()
            //配置淘汰最大条数策略
            .maximumSize(MAX_SIZE)
            //配置有效期单位（TimeUnit.DAYS天）
            .expireAfterWrite(DURATION, TimeUnit.DAYS)
            //加载缓存，当在本地缓存中找不到的时候，通过load方法将数据加载到缓存中，并返回给需        要的地方
            .build(new CacheLoader() {
                @Override
                public User load(@NonNull String userId) throws Exception {
                    HashMap objectObjectHashMap = new HashMap<>();
                    //查询数据库
                    User user = userMapper.selectUserById(userId);
                    return user;
                }
            });

    //获取缓存数据
    public User getData(String userId) {
        return cache.get(userId);
    }

    public void putData(User user) {
        cache.put(user.getUserId,user);
    }
}

3.使用Caffeine

@Slf4j
@Service
public class UserServiceImpl implements UserService{

    @Autowired
    private UserCache userCache;

    @Autowired
    private UserMapper userMapper;
    
    //从本地缓存获取数据
    public User getUserById(String userId){
        User user = userCache.getData(userId);
        if (user == null) { 
            //1. 如果没有，再尝试查询本地缓存
            synchronized (this.getClass()) {
                user = userCache.getData(userId);
                if (user == null) {       
                    User user=authAfterCache.getData(vin);
                    return user;
                }else {
                    log.info("再尝试查询本地缓存");
                    return user;
                }
            }
        } else {
            //2. 如果本地缓存有数据则直接返回
            return user;
        }
    }

    //从数据库获取数据再插入本地缓存
    public User putUser(String userId){
        User user=userMapper.selectUserById(userId);
        userCache.getData(user);
        return user;
    }

}