Latex公式表达式导出word文档

Latex公式导出，需将Latex公式表达式转换成MathML(数学标记语言) ，然后再将MathML(数学标记语言)转换成OMML(Word公式)，然后使用POI导出。

步骤如下所示：

1. 导入依赖

    de.rototor.snuggletex
    snuggletex-core
    1.3.0



    org.apache.poi
    poi
    4.1.2



    org.apache.poi
    ooxml-schemas
    1.4



    org.apache.poi
    poi-ooxml
    4.1.2


    commons-io
    commons-io
    2.11.0

2. 将Latex公式转换成MathML(数学标记语言)

public void addLatex(String latex, XWPFParagraph paragraph) throws Exception {
    paragraph.setAlignment(ParagraphAlignment.LEFT);
    paragraph.setFontAlignment(ParagraphAlignment.LEFT.getValue());
    SnuggleEngine engine = new uk.ac.ed.ph.snuggletex.SnuggleEngine();
    SnuggleSession session = engine.createSession();
    SnuggleInput input = new uk.ac.ed.ph.snuggletex.SnuggleInput(latex);
    session.parseInput(input);
    String mathML = session.buildXMLString();
    CTOMath ctOMath = getOMML(mathML);
    CTP ctp = paragraph.getCTP();
    CTOMath ctoMath = ctp.addNewOMath();
    ctoMath.set(ctOMath);
}

3. 将MathML(数学标记语言)转换成OMML(Word公式)

在windows的Office安装目录里面找到MML2OMML.XSL文件

将文件放入项目resources里

private CTOMath getOMML(String mathML) throws Exception {
    InputStream in = this.getClass().getClassLoader().getResourceAsStream("MML2OMML.XSL");
    TransformerFactory tFactory = TransformerFactory.newInstance();
    StreamSource stylesource = new StreamSource(in);
    Transformer transformer = tFactory.newTransformer(stylesource);
    StringReader stringreader = new StringReader(mathML);
    StreamSource source = new StreamSource(stringreader);
    StringWriter stringwriter = new StringWriter();
    StreamResult result = new StreamResult(stringwriter);
    transformer.transform(source, result);
    String ooML = stringwriter.toString();
    stringwriter.close();
    CTOMathPara ctOMathPara = CTOMathPara.Factory.parse(ooML);
    CTOMath ctOMath = ctOMathPara.getOMathArray(0);
    //for making this to work with Office 2007 Word also, special font settings are necessary
    XmlCursor xmlcursor = ctOMath.newCursor();
    while (xmlcursor.hasNextToken()) {
        XmlCursor.TokenType tokentype = xmlcursor.toNextToken();
        if (tokentype.isStart()) {
            if (xmlcursor.getObject() instanceof CTR) {
                CTR cTR = (CTR) xmlcursor.getObject();
                cTR.addNewRPr2().addNewRFonts().setAscii("Cambria Math");
                cTR.getRPr2().getRFonts().setHAnsi("Cambria Math"); // up to apache poi 4.1.2
                //cTR.getRPr2().getRFontsArray(0).setHAnsi("Cambria Math"); // since apache poi 5.0.0
            }
        }
    }
    return ctOMath;
}

4. 发现存在无法识别的符号

发现存在无法识别的符号，因此单独处理，提前过滤识别掉，①②③④⑤等符合无法识别，即latex表达式是 \textcircled

public class LatexUtils {
    public static String latexFilter(String latex){
        if(!latex.contains("textcircled")){
            return latex;
        }
        return TextCircledEnum.replaceTextCircled(latex);
    }

    private enum TextCircledEnum{
        Zero("\\\\textcircled\\{0\\}","⓪"),
        One("\\\\textcircled\\{1\\}","①"),
        Two("\\\\textcircled\\{2\\}","②"),
        Three("\\\\textcircled\\{3\\}","③"),
        Four("\\\\textcircled\\{4\\}","④"),
        Five("\\\\textcircled\\{5\\}","⑤"),
        Six("\\\\textcircled\\{6\\}","⑥"),
        Seven("\\\\textcircled\\{7\\}","⑦"),
        Eight("\\\\textcircled\\{8\\}","⑧"),
        Nine("\\\\textcircled\\{9\\}","⑨"),
        Ten("\\\\textcircled\\{10\\}","⑩");

        TextCircledEnum(String code, String v) {
            this.code = code;
            this.v = v;
        }

        public final String code;
        public final String v;

        public static String replaceTextCircled(String latex){
            for (TextCircledEnum c : TextCircledEnum.values()) {
                latex = latex.replaceAll(c.code,c.v);
            }
            return latex;
        }
    }
}

5. 调用

这里的latex表达式必须用$$包裹，例如：$S=4\pi R^{2}$

XWPFDocument document = new XWPFDocument();
XWPFParagraph paragraph = document.createParagraph();
paragraph.setAlignment(ParagraphAlignment.LEFT);
String latex = "$S=4\pi R^{2}$";
addLatex(LatexUtils.latexFilter(latex), document.createParagraph());