Mybatis执行Executor（一）

在DefaultSqlSession中我们可以看到一系列的增删改查操作的其实都是在调用Executor的接口，Mybatis对外统一提供了一个操作接口类Executor，提供的接口方法有update、query、flushStatements、commit、rollback等接口函数，源码如下：

/**
 * @author Clinton Begin
 */
public interface Executor {

  ResultHandler NO_RESULT_HANDLER = null;

  /* 更新操作**/
  int update(MappedStatement ms, Object parameter) throws SQLException;

  /* 查询操作*/
  <E> List<E> query(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, CacheKey cacheKey, BoundSql boundSql) throws SQLException;

  <E> List<E> query(MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler) throws SQLException;

  /* 更新statement操作*/
  List<BatchResult> flushStatements() throws SQLException;
  /*提交操作*/
  void commit(boolean required) throws SQLException;
  /*事务回滚操作*/
  void rollback(boolean required) throws SQLException;
  /*缓存key操作*/
  CacheKey createCacheKey(MappedStatement ms, Object parameterObject, RowBounds rowBounds, BoundSql boundSql);
  /*是否开启缓存*/
  boolean isCached(MappedStatement ms, CacheKey key);
  /*清除本地缓存操作*/
  void clearLocalCache();
  /*推迟加载操作*/
  void deferLoad(MappedStatement ms, MetaObject resultObject, String property, CacheKey key, Class<?> targetType);
  /*获取事务*/
  Transaction getTransaction();

  /*关闭连接*/
  void close(boolean forceRollback);

  boolean isClosed();

  void setExecutorWrapper(Executor executor);

}

Executor接口只是简单 的定义了一些基本的操作接口，具体实现类有抽象类BaseExecutor、实现类CachingExecutor、实现类BatchExecutor、实现类ReuseExecutor和实现类SimpleExecutor，这些实现类的具体操作我们在接下来的博客中会一步一步进行分析，如下图所示：