add null edit

hutool-poi/src/main/java/cn/hutool/poi/excel/RowUtil.java

@@ -73,7 +73,7 @@ public class RowUtil {
 		Object cellValue;
 		boolean isAllNull = true;
 		for (int i = startCellNumInclude; i < size; i++) {
-			cellValue = CellUtil.getCellValue(row.getCell(i), cellEditor);
+			cellValue = CellUtil.getCellValue(CellUtil.getCell(row, i), cellEditor);
 			isAllNull &= StrUtil.isEmptyIfStr(cellValue);
 			cellValues.add(cellValue);
 		}

hutool-poi/src/main/java/cn/hutool/poi/excel/cell/CellUtil.java

@@ -74,10 +74,7 @@ public class CellUtil {
 	 * @return 值，类型可能为：Date、Double、Boolean、String
 	 */
 	public static Object getCellValue(Cell cell, CellEditor cellEditor) {
-		if (null == cell) {
-			return null;
-		}
-		return getCellValue(cell, cell.getCellTypeEnum(), cellEditor);
+		return getCellValue(cell, null, cellEditor);
 	}
 
 	/**
@@ -105,6 +102,9 @@ public class CellUtil {
 		if (null == cell) {
 			return null;
 		}
+		if(cell instanceof NullCell){
+			return null == cellEditor ? null : cellEditor.edit(cell, null);
+		}
 		if (null == cellType) {
 			cellType = cell.getCellTypeEnum();
 		}
@@ -235,7 +235,23 @@ public class CellUtil {
 	}
 
 	/**
-	 * 获取已有行或创建新行
+	 *获取单元格，如果单元格不存在，返回{@link NullCell}
+	 *
+	 * @param row       Excel表的行
+	 * @param cellIndex 列号
+	 * @return {@link Row}
+	 * @since 5.5.0
+	 */
+	public static Cell getCell(Row row, int cellIndex) {
+		Cell cell = row.getCell(cellIndex);
+		if (null == cell) {
+			return new NullCell(row, cellIndex);
+		}
+		return cell;
+	}
+
+	/**
+	 * 获取已有单元格或创建新单元格
 	 *
 	 * @param row       Excel表的行
 	 * @param cellIndex 列号

hutool-poi/src/main/java/cn/hutool/poi/excel/cell/NullCell.java

@@ -0,0 +1,240 @@
+package cn.hutool.poi.excel.cell;
+
+import org.apache.poi.ss.formula.FormulaParseException;
+import org.apache.poi.ss.usermodel.Cell;
+import org.apache.poi.ss.usermodel.CellStyle;
+import org.apache.poi.ss.usermodel.CellType;
+import org.apache.poi.ss.usermodel.Comment;
+import org.apache.poi.ss.usermodel.Hyperlink;
+import org.apache.poi.ss.usermodel.RichTextString;
+import org.apache.poi.ss.usermodel.Row;
+import org.apache.poi.ss.usermodel.Sheet;
+import org.apache.poi.ss.util.CellAddress;
+import org.apache.poi.ss.util.CellRangeAddress;
+
+import java.time.LocalDateTime;
+import java.util.Calendar;
+import java.util.Date;
+
+/**
+ * 当单元格不存在时使用此对象表示，得到的值都为null,此对象只用于标注单元格所在位置信息。
+ *
+ * @author looly
+ * @since 5.5.0
+ */
+public class NullCell implements Cell {
+
+	private final Row row;
+	private final int columnIndex;
+
+	/**
+	 * 构造
+	 *
+	 * @param row         行
+	 * @param columnIndex 列号，从0开始
+	 */
+	public NullCell(Row row, int columnIndex) {
+		this.row = row;
+		this.columnIndex = columnIndex;
+	}
+
+	@Override
+	public int getColumnIndex() {
+		return this.columnIndex;
+	}
+
+	@Override
+	public int getRowIndex() {
+		return getRow().getRowNum();
+	}
+
+	@Override
+	public Sheet getSheet() {
+		return getRow().getSheet();
+	}
+
+	@Override
+	public Row getRow() {
+		return this.row;
+	}
+
+	@Override
+	public void setCellType(CellType cellType) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setBlank() {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public CellType getCellType() {
+		return null;
+	}
+
+	@Override
+	public CellType getCellTypeEnum() {
+		return null;
+	}
+
+	@Override
+	public CellType getCachedFormulaResultType() {
+		return null;
+	}
+
+	@Override
+	public CellType getCachedFormulaResultTypeEnum() {
+		return null;
+	}
+
+	@Override
+	public void setCellValue(double value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setCellValue(Date value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setCellValue(LocalDateTime value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setCellValue(Calendar value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setCellValue(RichTextString value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setCellValue(String value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setCellFormula(String formula) throws FormulaParseException, IllegalStateException {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void removeFormula() throws IllegalStateException {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public String getCellFormula() {
+		return null;
+	}
+
+	@Override
+	public double getNumericCellValue() {
+		throw new UnsupportedOperationException("Cell value is null!");
+	}
+
+	@Override
+	public Date getDateCellValue() {
+		return null;
+	}
+
+	@Override
+	public LocalDateTime getLocalDateTimeCellValue() {
+		return null;
+	}
+
+	@Override
+	public RichTextString getRichStringCellValue() {
+		return null;
+	}
+
+	@Override
+	public String getStringCellValue() {
+		return null;
+	}
+
+	@Override
+	public void setCellValue(boolean value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void setCellErrorValue(byte value) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public boolean getBooleanCellValue() {
+		throw new UnsupportedOperationException("Cell value is null!");
+	}
+
+	@Override
+	public byte getErrorCellValue() {
+		throw new UnsupportedOperationException("Cell value is null!");
+	}
+
+	@Override
+	public void setCellStyle(CellStyle style) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public CellStyle getCellStyle() {
+		return null;
+	}
+
+	@Override
+	public void setAsActiveCell() {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public CellAddress getAddress() {
+		return null;
+	}
+
+	@Override
+	public void setCellComment(Comment comment) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public Comment getCellComment() {
+		return null;
+	}
+
+	@Override
+	public void removeCellComment() {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public Hyperlink getHyperlink() {
+		return null;
+	}
+
+	@Override
+	public void setHyperlink(Hyperlink link) {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public void removeHyperlink() {
+		throw new UnsupportedOperationException("Can not set any thing to null cell!");
+	}
+
+	@Override
+	public CellRangeAddress getArrayFormulaRange() {
+		return null;
+	}
+
+	@Override
+	public boolean isPartOfArrayFormulaGroup() {
+		throw new UnsupportedOperationException("Cell value is null!");
+	}
+}

hutool-poi/src/test/java/cn/hutool/poi/excel/test/ExcelReadTest.java

@@ -3,6 +3,7 @@ package cn.hutool.poi.excel.test;
 import cn.hutool.core.io.resource.ResourceUtil;
 import cn.hutool.core.lang.Console;
 import cn.hutool.core.map.MapUtil;
+import cn.hutool.core.util.ObjectUtil;
 import cn.hutool.poi.excel.ExcelReader;
 import cn.hutool.poi.excel.ExcelUtil;
 import lombok.Data;
@@ -201,4 +202,20 @@ public class ExcelReadTest {
 			Console.log(list);
 		}
 	}
+
+	@Test
+	public void nullValueEditTest(){
+		final ExcelReader reader = ExcelUtil.getReader("null_cell_test.xlsx");
+		reader.setCellEditor((cell, value)-> ObjectUtil.defaultIfNull(value, "#"));
+		final List<List<Object>> read = reader.read();
+
+		// 对于任意一个单元格有值的情况下，之前的单元格值按照null处理
+		Assert.assertEquals(1, read.get(1).size());
+		Assert.assertEquals(2, read.get(2).size());
+		Assert.assertEquals(3, read.get(3).size());
+
+		Assert.assertEquals("#", read.get(2).get(0));
+		Assert.assertEquals("#", read.get(3).get(0));
+		Assert.assertEquals("#", read.get(3).get(1));
+	}
 }