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java - 如何在 Apache POI 中重用字体?

转载 作者:行者123 更新时间:2023-12-02 09:25:51 28 4
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每次调用“workbook.createFont()”都会向工作簿添加新字体。有没有方便的方法来重用这些字体?

显然,我可以在程序中重用字体对象。但是当我重新打开Java程序时,我需要一种方法来取回Font对象。

虽然可以使用“workbook.getNumberOfFonts()”和“workbook.getFontAt(i)”,但使用这些方法并不是很方便。

我的解决方法:
我在创建字体的时候添加了一个CustomProperty,里面保存了字体对应的编号。

Map<String, Font> fonts = new HashMap<>();

CustomProperties customProps = workbook.getProperties().getCustomProperties();

if(customProps.contains("arial_12_b")) {
short index = customProps.getProperty("arial_12_b").getI2();
fonts.put("arial_12_b", workbook.getFontAt(index));
} else {
Font font = workbook.createFont();
font.setFontName("Arial");
font.setFontHeightInPoints((short)12);
font.setBold(true);

customProps.addProperty("arial_12_b", font.getIndex());

fonts.put("arial_12_b", font);
}

CellStyle 通过 CellUtil 类解决了同样的问题,该类检查 CellStyle 是否已存在,如果不存在则创建它。有类似 Font 的东西吗?

最诚挚的问候
AFeeee

最佳答案

可以提供一种使用 Workbook.findFont 的方法达到你所要求的目的。就像 CellUtil.setCellStyleProperties它可以使用 Map<FontProperty, Object> fontproperties设置字体属性,其中 FontProperty是所有属性的枚举 Workbook.findFont目前正在检查。目前是粗体、颜色、字体高度、字体名称、斜体、删除线、类型偏移、下划线。

示例:

 //method for getting current font from cell
private static Font getFont(Cell cell) {
Workbook wb = cell.getRow().getSheet().getWorkbook();
CellStyle style = cell.getCellStyle();
return wb.getFontAt(style.getFontIndex());
}

private enum FontProperty {
BOLD, COLOR, FONTHEIGHT, FONTNAME, ITALIC, STRIKEOUT, TYPEOFFSET, UNDERLINE
}

//method for getting font having special settings additional to given source font
private static Font getFont(Workbook wb, Font fontSrc, Map<FontProperty, Object> fontproperties) {
boolean isBold = fontSrc.getBold();
short color = fontSrc.getColor();
short fontHeight = fontSrc.getFontHeight();
String fontName = fontSrc.getFontName();
boolean isItalic = fontSrc.getItalic();
boolean isStrikeout = fontSrc.getStrikeout();
short typeOffset = fontSrc.getTypeOffset();
byte underline = fontSrc.getUnderline();

for (FontProperty property : fontproperties.keySet()) {
switch (property) {
case BOLD:
isBold = (boolean)fontproperties.get(property);
break;
case COLOR:
color = (short)fontproperties.get(property);
break;
case FONTHEIGHT:
fontHeight = (short)fontproperties.get(property);
break;
case FONTNAME:
fontName = (String)fontproperties.get(property);
break;
case ITALIC:
isItalic = (boolean)fontproperties.get(property);
break;
case STRIKEOUT:
isStrikeout = (boolean)fontproperties.get(property);
break;
case TYPEOFFSET:
typeOffset = (short)fontproperties.get(property);
break;
case UNDERLINE:
underline = (byte)fontproperties.get(property);
break;
}
}

Font font = wb.findFont(isBold, color, fontHeight, fontName, isItalic, isStrikeout, typeOffset, underline);
if (font == null) {
font = wb.createFont();
font.setBold(isBold);
font.setColor(color);
font.setFontHeight(fontHeight);
font.setFontName(fontName);
font.setItalic(isItalic);
font.setStrikeout(isStrikeout);
font.setTypeOffset(typeOffset);
font.setUnderline(underline);
}

return font;
}

在此代码中Workbook.findFont用于尝试找到已经具有所有属性的字体。仅当未找到此字体 ( if (font == null) ) 时,才会创建新字体。

使用方法:

  //set new cell D6 having special font settings
row = CellUtil.getRow(5, sheet);
cell = CellUtil.getCell(row, 3);
fontproperties = new HashMap<FontProperty, Object>();
fontproperties.put(FontProperty.BOLD, true);
fontproperties.put(FontProperty.COLOR, IndexedColors.BLUE.getIndex());
fontproperties.put(FontProperty.FONTHEIGHT, (short)(20*20));
fontproperties.put(FontProperty.FONTNAME, "Courier New");
fontproperties.put(FontProperty.STRIKEOUT, true);
fontproperties.put(FontProperty.UNDERLINE, Font.U_DOUBLE);
font = getFont(wb, getFont(cell), fontproperties);
styleproperties = new HashMap<String, Object>();
styleproperties.put(CellUtil.FONT, font.getIndex());
CellUtil.setCellStyleProperties(cell, styleproperties);
cell.setCellValue("new cell");

参见How to format Excel Cell as Date in Apache POI获取完整示例。

关于java - 如何在 Apache POI 中重用字体?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49617520/

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