<configuration>
  <settings>
    <!-- 開(kāi)啟二級(jí)緩存 -->
    <setting name="cacheEnabled" value="true"/>
  </settings>
  <typeAliases>
    <!-- 定義緩存實(shí)體類 -->
    <typeAlias type="com.example.User" alias="User"/>
  </typeAliases>
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
      </dataSource>
      <!-- 配置Redis緩存 -->
      <cache type="com.example.RedisCache"/>
    </environment>
  </environments>
  <mappers>
    <!-- 定義Mapper接口 -->
    <mapper class="com.example.UserMapper"/>
  </mappers>
</configuration>

public class RedisCache implements Cache {
  private static final Logger logger = LoggerFactory.getLogger(RedisCache.class);
  private final String id;
  private final RedisTemplate<String, Object> redisTemplate;
  private static final long EXPIRE_TIME_IN_SECONDS = 60 * 60 * 24;
  public RedisCache(String id) {
    if (id == null) {
      throw new IllegalArgumentException("Cache instances require an ID");
    }
    this.id = id;
    redisTemplate = new RedisTemplate<>();
    redisTemplate.setConnectionFactory(new JedisConnectionFactory());
    redisTemplate.setKeySerializer(new StringRedisSerializer());
    redisTemplate.setValueSerializer(new JdkSerializationRedisSerializer());
    redisTemplate.afterPropertiesSet();
  }
  @Override
  public String getId() {
    return id;
  }
  @Override
  public void putObject(Object key, Object value) {
    logger.debug("Putting object in Redis cache");
    redisTemplate.opsForValue().set(key.toString(), value, EXPIRE_TIME_IN_SECONDS, TimeUnit.SECONDS);
  }
  @Override
  public Object getObject(Object key) {
    logger.debug("Getting object from Redis cache");
    return redisTemplate.opsForValue().get(key.toString());
  }
  @Override
  public Object removeObject(Object key) {
    logger.debug("Removing object from Redis cache");
    redisTemplate.delete(key.toString());
    return null;
  }
  @Override
  public void clear() {
    logger.debug("Clearing Redis cache");
    redisTemplate.execute((RedisCallback<Void>) connection -> {
      connection.flushDb();
      return null;
    });
  }
  @Override
  public int getSize() {
    logger.debug("Getting size of Redis cache");
    return redisTemplate.execute((RedisCallback<Integer>) connection -> {
      return (int) connection.dbSize();
    });
  }
  @Override
  public ReadWriteLock getReadWriteLock() {
    return null;
  }
}

public interface UserMapper {
  @Select("SELECT * FROM user WHERE id = #{id}")
  @Results({
    @Result(property = "id", column = "id"),
    @Result(property = "name", column = "name"),
    @Result(property = "age", column = "age")
  })
  // 使用二級(jí)緩存
  @Cacheable(namespace = "User", key = "#id")
  User findById(Long id);
}