Mybatis提供了一個簡單的邏輯分頁使用類RowBounds（物理分頁當然就是我們在sql語句中指定limit和offset值），在DefaultSqlSession提供的某些查詢介面中我們可以看到RowBounds是作為引數用來進行分頁的，如下介面：

 public <E> List<E> selectList(String statement, Object parameter, RowBounds rowBounds)

public class RowBounds {

  /* 預設offset是0**/
  public static final int NO_ROW_OFFSET = 0;
  
  /* 預設Limit是int的最大值，因此它使用的是邏輯分頁**/
  public static final int NO_ROW_LIMIT = Integer.MAX_VALUE;
  public static final RowBounds DEFAULT = new RowBounds();

  private int offset;
  private int limit;

  public RowBounds() {
    this.offset = NO_ROW_OFFSET;
    this.limit = NO_ROW_LIMIT;
  }

  public RowBounds(int offset, int limit) {
    this.offset = offset;
    this.limit = limit;
  }

  public int getOffset() {
    return offset;
  }

  public int getLimit() {
    return limit;
  }

}
 

在DefaultResultSetHandler中，邏輯分頁會將所有的結果都查詢到，然後根據RowBounds中提供的offset和limit值來獲取最後的結果，DefaultResultSetHandler實現如下：

private void handleRowValuesForSimpleResultMap(ResultSetWrapper rsw, ResultMap resultMap, ResultHandler<?> resultHandler, RowBounds rowBounds, ResultMapping parentMapping)
      throws SQLException {
    DefaultResultContext<Object> resultContext = new DefaultResultContext<Object>();
	//跳過RowBounds設定的offset值
    skipRows(rsw.getResultSet(), rowBounds);
	//判斷資料是否小於limit，如果小於limit的話就不斷的迴圈取值
    while (shouldProcessMoreRows(resultContext, rowBounds) && rsw.getResultSet().next()) {
      ResultMap discriminatedResultMap = resolveDiscriminatedResultMap(rsw.getResultSet(), resultMap, null);
      Object rowValue = getRowValue(rsw, discriminatedResultMap);
      storeObject(resultHandler, resultContext, rowValue, parentMapping, rsw.getResultSet());
    }
  }
private boolean shouldProcessMoreRows(ResultContext<?> context, RowBounds rowBounds) throws SQLException {
	//判斷資料是否小於limit，小於返回true
    return !context.isStopped() && context.getResultCount() < rowBounds.getLimit();
  }
  //跳過不需要的行,應該就是rowbounds設定的limit和offset
  private void skipRows(ResultSet rs, RowBounds rowBounds) throws SQLException {
    if (rs.getType() != ResultSet.TYPE_FORWARD_ONLY) {
      if (rowBounds.getOffset() != RowBounds.NO_ROW_OFFSET) {
        rs.absolute(rowBounds.getOffset());
      }
    } else {
	  //跳過RowBounds中設定的offset條資料
      for (int i = 0; i < rowBounds.getOffset(); i++) {
        rs.next();
      }
    }
  }