mybatis源码解读之executor包语句处理功能

public class RoutingStatementHandler implements StatementHandler {

  // 根据语句类型选取出的被代理类的对象
  private final StatementHandler delegate;

  public RoutingStatementHandler(Executor executor, MappedStatement ms, Object parameter, RowBounds rowBounds, ResultHandler resultHandler, BoundSql boundSql) {
    // 根据语句类型选择被代理对象
    switch (ms.getStatementType()) {
      case STATEMENT:
        delegate = new SimpleStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql);
        break;
      case PREPARED:
        delegate = new PreparedStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql);
        break;
      case CALLABLE:
        delegate = new CallableStatementHandler(executor, ms, parameter, rowBounds, resultHandler, boundSql);
        break;
      default:
        throw new ExecutorException("Unknown statement type: " + ms.getStatementType());
    }
  }
}

public class SimpleStatementHandler extends BaseStatementHandler {

 @Override
  public void parameterize(Statement statement) {
    // N/A
  }

  }

public class PreparedStatementHandler extends BaseStatementHandler {
  @Override
  public void parameterize(Statement statement) throws SQLException {
    parameterHandler.setParameters((PreparedStatement) statement);
  }
}

public class CallableStatementHandler extends BaseStatementHandler {
 /**
   * 对语句进行参数处理
   * @param statement SQL语句
   * @throws SQLException
   */
  @Override
  public void parameterize(Statement statement) throws SQLException {
    // 输出参数的注册
    registerOutputParameters((CallableStatement) statement);
    // 输入参数的处理
    parameterHandler.setParameters((CallableStatement) statement);
  }

}