Java POI Excel 行高自适应

  在Excel处理的过程中，可能有需要用到行高自适应的时候。

  下面贴出用POI实现Excel行高自适应的代码。

  该代码可以处理一行Excel按内容自适应高度。可以处理合并单元格。

  上代码：

/**
	 * 根据行内容重新计算行高
	 * @param row
	 */
	public static void calcAndSetRowHeigt(HSSFRow sourceRow) {
		for (int cellIndex = sourceRow.getFirstCellNum(); cellIndex <= sourceRow.getPhysicalNumberOfCells(); cellIndex++) {
			//行高
			double maxHeight = sourceRow.getHeight();
			HSSFCell sourceCell = sourceRow.getCell(cellIndex);
			//单元格的内容
			String cellContent = getCellContentAsString(sourceCell);
			if(null == cellContent || "".equals(cellContent)){
				continue;
			}
			//单元格的宽高及单元格信息
			Map<String, Object> cellInfoMap = getCellInfo(sourceCell);
			Integer cellWidth = (Integer)cellInfoMap.get("width");
			Integer cellHeight = (Integer)cellInfoMap.get("height");
			if(cellHeight > maxHeight){
				maxHeight = cellHeight;
			}
			System.out.println("单元格的宽度 : " + cellWidth + "    单元格的高度 : " + maxHeight + ",    单元格的内容 : " + cellContent);
			HSSFCellStyle cellStyle = sourceCell.getCellStyle();
			HSSFFont font = cellStyle.getFont(sourceRow.getSheet().getWorkbook());
			//字体的高度
			short fontHeight = font.getFontHeight();
			
			//cell内容字符串总宽度
			double cellContentWidth = cellContent.getBytes().length * 2 * 256;
			
	        //字符串需要的行数 不做四舍五入之类的操作
	        double stringNeedsRows =(double)cellContentWidth / cellWidth;
	        //小于一行补足一行
	        if(stringNeedsRows < 1.0){
	        	stringNeedsRows = 1.0;
	        }
	        
	        //需要的高度 			(Math.floor(stringNeedsRows) - 1) * 40 为两行之间空白高度
	        double stringNeedsHeight = (double)fontHeight * stringNeedsRows;
	        //需要重设行高
	        if(stringNeedsHeight > maxHeight){
	        	maxHeight = stringNeedsHeight;
	        	//超过原行高三倍 则为5倍 实际应用中可做参数配置
	    		if(maxHeight/cellHeight > 5){
	    			maxHeight = 5 * cellHeight;
	    		}
	    		//最后取天花板防止高度不够
	    		maxHeight = Math.ceil(maxHeight);
	    		//重新设置行高 同时处理多行合并单元格的情况
	    		Boolean isPartOfRowsRegion = (Boolean)cellInfoMap.get("isPartOfRowsRegion");
	    		if(isPartOfRowsRegion){
	    			Integer firstRow = (Integer)cellInfoMap.get("firstRow");
	    			Integer lastRow = (Integer)cellInfoMap.get("lastRow");
	    			//平均每行需要增加的行高
	    			double addHeight = (maxHeight - cellHeight)/(lastRow - firstRow + 1);
	    			for (int i = firstRow; i <= lastRow; i++) {
	    				double rowsRegionHeight =sourceRow.getSheet().getRow(i).getHeight() + addHeight;
	    				sourceRow.getSheet().getRow(i).setHeight((short)rowsRegionHeight);
	    			}
	    		}else{
	    			sourceRow.setHeight((short)maxHeight);
	    		}
	        }
	        System.out.println("字体高度 : " + fontHeight + ",    字符串宽度 : " + cellContentWidth + ",    字符串需要的行数 : " + stringNeedsRows + ",   需要的高度 : " + stringNeedsHeight + ",   现在的行高 : " + maxHeight);
	        System.out.println();
		}
	}
	
	/**
	 * 解析一个单元格得到数据
	 * @param cell
	 * @return
	 */
	private static String getCellContentAsString(HSSFCell cell) {
		if(null == cell){
			return "";
		}
		String result = "";
		switch (cell.getCellType()) {
		case Cell.CELL_TYPE_NUMERIC:
			String s = String.valueOf(cell.getNumericCellValue());
			if (s != null) {
				if (s.endsWith(".0")) {
					s = s.substring(0, s.length() - 2);
				}
			}
			result = s;
			break;
		case Cell.CELL_TYPE_STRING:
			result = ToolKits.nulltoempty(String.valueOf(cell.getStringCellValue())).trim();
			break;
		case Cell.CELL_TYPE_BLANK:
			break;
		case Cell.CELL_TYPE_BOOLEAN:
			result = String.valueOf(cell.getBooleanCellValue());
			break;
		case Cell.CELL_TYPE_ERROR:
			break;
		default:
			break;
		}
		return result;
	}
	
	/**
     * 获取单元格及合并单元格的宽度
     * @param cell
     * @return
     */
    private static Map<String, Object> getCellInfo(HSSFCell cell) {
    	HSSFSheet sheet = cell.getSheet();
    	int rowIndex = cell.getRowIndex();
    	int columnIndex = cell.getColumnIndex();
    	
    	boolean isPartOfRegion = false;
    	int firstColumn = 0;
    	int lastColumn = 0;
    	int firstRow = 0;
    	int lastRow = 0;
		int sheetMergeCount = sheet.getNumMergedRegions();
		for (int i = 0; i < sheetMergeCount; i++) {
			Region ca = sheet.getMergedRegionAt(i);
			firstColumn = ca.getColumnFrom();
			lastColumn = ca.getColumnTo();
			firstRow = ca.getRowFrom();
			lastRow = ca.getRowTo();
			if (rowIndex >= firstRow && rowIndex <= lastRow) {
				if (columnIndex >= firstColumn && columnIndex <= lastColumn) {
					isPartOfRegion = true;
					break;
				}
			}
		}
		Map<String, Object> map = new HashMap<String, Object>();
		Integer width = 0;
		Integer height = 0;
		boolean isPartOfRowsRegion = false;
		if(isPartOfRegion){
			for (int i = firstColumn; i <= lastColumn; i++) {
				width += sheet.getColumnWidth(i);
			}
			for (int i = firstRow; i <= lastRow; i++) {
				height += sheet.getRow(i).getHeight();
			}
			if(lastRow > firstRow){
				isPartOfRowsRegion = true;
			}
		}else{
			width = sheet.getColumnWidth(columnIndex);
			height += cell.getRow().getHeight();
		}
		map.put("isPartOfRowsRegion", isPartOfRowsRegion);
		map.put("firstRow", firstRow);
		map.put("lastRow", lastRow);
		map.put("width", width);
		map.put("height", height);
		return map;
	}

评论

1 楼 zenghongqing 2015-01-19  

您好，请教您一个问题：
//cell内容字符串总宽度 
double cellContentWidth = cellContent.getBytes().length * 2 * 256;
这一段代码为什么要乘以256？这个算字符串的宽度必须要乘256吗？为什么不是乘一个别的数？