Spring Boot 使用 Redis 做缓存

这里有两种方式

• 使用注解方式（但是小爷不喜欢）
• 直接《Spring Boot 使用 Redis》中的redisTemplate

1、创建UserService

public interface UserService {
    public User findById(int id);
    public User create(User user);
    public User update(User user);
    public void delete(int id);
}

2、创建UserServiceImpl

@Servicepublic class UserServiceImpl implements UserService {
    @Autowired
    private UserRepository userRepository;
    @Autowired
    private UserRedis userRedis;
    //this is a key for redis
    private static final String keyHead = "mysql:get:user:";
    
    @Override
    public User findById(int id) {
        User user = userRedis.get(keyHead+id);
        if (user == null) {
            user = userRepository.findOne(id);
            if (user != null) {
                userRedis.add(keyHead+id, 30L, user);
            }
        }
        return user;
    }

    @Override
    public User create(User user) {
        User newUser = userRepository.save(user);
        if (newUser != null) {
            userRedis.add(keyHead+newUser.getId(), 30L, newUser);
        }
        return newUser;
    }

    @Override
    public User update(User user) {
        if (user != null) {
            userRedis.delete(keyHead+user.getId());
            userRedis.add(keyHead+user.getId(), 30L, user);
        }
        return userRepository.save(user);
    }

    @Override
    public void delete(int id) {
        userRedis.delete(keyHead+id);
        userRepository.delete(id);
    }
}

3、创建UserController

@RestController
@RequestMapping("/users")
public class UserController {
    @Autowired
    private UserService userService;
    @RequestMapping(value = "/{id}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public Object show(@PathVariable int id) {
        User user = userService.findById(id);
        return user;
    }
}

4、结果，在30分钟内只会执行一次查询