Mybatis的executor

前提：一级缓存与二级缓存，可见：https://www.cnblogs.com/yanze/p/10175017.html

简介：

Executor与SqlSession绑定在一起，每一个SqlSession都拥有一个新的Executor对象，Executor可以认为是SqlSession的核心。

Executor类图如下:

Mybatis的executor

Executor

顶层接口，定义基本操作

public interface Executor {

  ResultHandler NO_RESULT_HANDLER = null;
  // 更新
  int update(MappedStatement ms, Object parameter) throws SQLException;
  // 查询，先查缓存，再查数据库
  <E> List<E> query(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, CacheKey cacheKey, BoundSql boundSql) throws SQLException;
  // 查询
  <E> List<E> query(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler) throws SQLException;

  <E> Cursor<E> queryCursor(MappedStatement ms, Object parameter, RowBounds rowBounds) throws SQLException;

  List<BatchResult> flushStatements() throws SQLException;
  // 事务提交
  void commit(boolean required) throws SQLException;
  // 事务回滚
  void rollback(boolean required) throws SQLException;
  // 创建缓存的键对象
  CacheKey createCacheKey(MappedStatement ms, Object parameterObject, RowBounds rowBounds, BoundSql boundSql);
  // 缓存中是否有这个查询的结果
  boolean isCached(MappedStatement ms, CacheKey key);
  // 清空缓存
  void clearLocalCache();

  void deferLoad(MappedStatement ms, MetaObject resultObject, String property, CacheKey key, Class<?> targetType);

  Transaction getTransaction();

  void close(boolean forceRollback);

  boolean isClosed();

  void setExecutorWrapper(Executor executor);

}

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