通常，不必创建太多可能超出单元格样式最大数量的单元格样式。要根据其内容格式化单元格，可以使用条件格式化。同样，为了格式化行（例如奇/偶行不同），可以使用条件格式。也用于列。
因此，通常不应该使用单元格样式来格式化每个单元格或大量单元格。相反，应该创建较少的单元格样式，然后将其用作默认单元格样式，或者在个别情况下，如果真的无法进行条件格式设置，则可以将其用作单元格样式。
在我的示例中，我为所有单元格设置了默认的单元格样式，为第一行设置了一个单行单元格样式（即使使用条件格式也可以实现）。
若要在将默认单元格样式应用于所有列后保持其正常工作，必须将其应用于具有
apachepoi新创建的单元格的所有单元格。为此，我提供了一种方法
getPreferredCellStyle(Cellcell)。
Excel本身会自动将列（或行）单元格样式应用于新填充的单元格。
但是，如果仍然有必要格式化不同的单个单元格，则应使用此CellUtil。这提供了“各种处理样式的方法，使您可以根据需要创建CellStyles。将样式更改应用于单元格时，代码将尝试查看是否已经存在满足您需求的样式。如果不存在，则它将创建一个新样式。这是为了防止创建太多样式。Excel中可以支持的样式数量有上限。”
请参阅示例中的注释。
import java.io.*;import org.apache.poi.ss.usermodel.*;import org.apache.poi.xssf.usermodel.*;import org.apache.poi.ss.util.CellUtil;import java.util.Map;import java.util.HashMap;public class CarefulCreateCellStyles { public CellStyle getPreferredCellStyle(Cell cell) { // a method to get the preferred cell style for a cell // this is either the already applied cell style // or if that not present, then the row style (default cell style for this row) // or if that not present, then the column style (default cell style for this column) CellStyle cellStyle = cell.getCellStyle(); if (cellStyle.getIndex() == 0) cellStyle = cell.getRow().getRowStyle(); if (cellStyle == null) cellStyle = cell.getSheet().getColumnStyle(cell.getColumnIndex()); if (cellStyle == null) cellStyle = cell.getCellStyle(); return cellStyle; } public CarefulCreateCellStyles() throws Exception { Workbook workbook = new XSSFWorkbook(); // at first we are creating needed fonts Font defaultFont = workbook.createFont(); defaultFont.setFontName("Arial"); defaultFont.setFontHeightInPoints((short)14); Font specialfont = workbook.createFont(); specialfont.setFontName("Courier New"); specialfont.setFontHeightInPoints((short)18); specialfont.setBold(true); // now we are creating a default cell style which will then be applied to all cells CellStyle defaultCellStyle = workbook.createCellStyle(); defaultCellStyle.setFont(defaultFont); // maybe sone rows need their own default cell style CellStyle aRowCellStyle = workbook.createCellStyle(); aRowCellStyle.cloneStyleFrom(defaultCellStyle); aRowCellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND); aRowCellStyle.setFillForegroundColor((short)3); Sheet sheet = workbook.createSheet("Sheet1"); // apply default cell style as column style to all columns org.openxmlformats.schemas.spreadsheetml.x2006.main.CTCol cTCol = ((XSSFSheet)sheet).getCTWorksheet().getColsArray(0).addNewCol(); cTCol.setMin(1); cTCol.setMax(workbook.getSpreadsheetVersion().getLastColumnIndex()); cTCol.setWidth(20 + 0.7109375); cTCol.setStyle(defaultCellStyle.getIndex()); // creating cells Row row = sheet.createRow(0); row.setRowStyle(aRowCellStyle); Cell cell = null; for (int c = 0; c < 3; c++) { cell = CellUtil.createCell(row, c, "Header " + (c+1)); // we get the preferred cell style for each cell we are creating cell.setCellStyle(getPreferredCellStyle(cell)); } System.out.println(workbook.getNumCellStyles()); // 3 = 0(default) and 2 just created row = sheet.createRow(1); cell = CellUtil.createCell(row, 0, "centered"); cell.setCellStyle(getPreferredCellStyle(cell)); CellUtil.setAlignment(cell, HorizontalAlignment.CENTER); System.out.println(workbook.getNumCellStyles()); // 4 = 0 and 3 just created cell = CellUtil.createCell(row, 1, "bordered"); cell.setCellStyle(getPreferredCellStyle(cell)); Map<String, Object> properties = new HashMap<String, Object>(); properties.put(CellUtil.BORDER_LEFT, BorderStyle.THICK); properties.put(CellUtil.BORDER_RIGHT, BorderStyle.THICK); properties.put(CellUtil.BORDER_TOP, BorderStyle.THICK); properties.put(CellUtil.BORDER_BOTTOM, BorderStyle.THICK); CellUtil.setCellStyleProperties(cell, properties); System.out.println(workbook.getNumCellStyles()); // 5 = 0 and 4 just created cell = CellUtil.createCell(row, 2, "other font"); cell.setCellStyle(getPreferredCellStyle(cell)); CellUtil.setFont(cell, specialfont); System.out.println(workbook.getNumCellStyles()); // 6 = 0 and 5 just created// until now we have always created new cell styles. but from now on CellUtil will use// already present cell styles if they matching the needed properties. row = sheet.createRow(2); cell = CellUtil.createCell(row, 0, "bordered"); cell.setCellStyle(getPreferredCellStyle(cell)); properties = new HashMap<String, Object>(); properties.put(CellUtil.BORDER_LEFT, BorderStyle.THICK); properties.put(CellUtil.BORDER_RIGHT, BorderStyle.THICK); properties.put(CellUtil.BORDER_TOP, BorderStyle.THICK); properties.put(CellUtil.BORDER_BOTTOM, BorderStyle.THICK); CellUtil.setCellStyleProperties(cell, properties); System.out.println(workbook.getNumCellStyles()); // 6 = nothing new created cell = CellUtil.createCell(row, 1, "other font"); cell.setCellStyle(getPreferredCellStyle(cell)); CellUtil.setFont(cell, specialfont); System.out.println(workbook.getNumCellStyles()); // 6 = nothing new created cell = CellUtil.createCell(row, 2, "centered"); cell.setCellStyle(getPreferredCellStyle(cell)); CellUtil.setAlignment(cell, HorizontalAlignment.CENTER); System.out.println(workbook.getNumCellStyles()); // 6 = nothing new created FileOutputStream out = new FileOutputStream("CarefulCreateCellStyles.xlsx"); workbook.write(out); out.close(); workbook.close(); } public static void main(String[] args) throws Exception { CarefulCreateCellStyles carefulCreateCellStyles = new CarefulCreateCellStyles(); }}
