缓存设计模式

缓存热点数据, 缩短调用链

旁路缓存

适用于强一致性

• 写请求 -> 更新DB, 并删除cache
• 读请求 -> 先查cache, miss后再查DB并写回

@Service
public class UserService{

    @Autowired
    private UserDAO userDAO;

    private RedisTemplate redisTemplate;

    public User getUserById(Integer id) {
        User user = redisTemplate.opForObject();
        if (user == null) {
            user = userDAO.getUserById(id);
            if (user != null) {
                redisTemplate.update();
            }
        }
    }

    public void updateUser(User user) {
        Integer id = user.getId();
        userDAO.updateUser(user);
        redisTemplate.delete(id);
    }
}