java - 使用 Apache POI 在 word (.docx) 中添加 latex 类型方程

Question

我正在尝试使用 Apache POI 创建自动 (.docx) MS Word 文件。 Java程序的输入包含文本、图像和LaTeX风格的方程(嵌入$$或[])。

我的问题是如何在 Word 中添加这个 LaTeX 样式方程，以便当在 MS Word 中编辑 .docx 文件时，它会将方程识别为 MS Word 样式方程(OMML 类型)

注意:我认为应该将 LaTeX 方程转换为 MathML。如果是这样，那么如何将 MathML 添加到 .docx 中？

Answer 1

Microsoft 提供了 XSLT 样式表，用于将 OMML 转换为 MathML (OMML2MML.XSL) 以及使用 XSLT 将 MathML 转换为 OMML (MML2OMML.XSL).

如果您已安装 Microsoft Office，您将在 Office 程序目录中找到这些文件。在我的系统中:

使用它，我们可以使用 XSLT 将 MathML 转换为 OMML。

示例:

import java.io.*;
import org.apache.poi.xwpf.usermodel.*;

import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTP;
import org.openxmlformats.schemas.officeDocument.x2006.math.CTOMath;
import org.openxmlformats.schemas.officeDocument.x2006.math.CTOMathPara;
import org.openxmlformats.schemas.officeDocument.x2006.math.CTR;

import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.xmlbeans.XmlCursor;

/*
needs the full ooxml-schemas-*.jar or poi-ooxml-full-5.0.0.jar as mentioned in https://poi.apache.org/faq.html#faq-N10025
*/

public class CreateWordFormulaFromMathML {

 static File stylesheet = new File("MML2OMML.XSL");
 static TransformerFactory tFactory = TransformerFactory.newInstance();
 static StreamSource stylesource = new StreamSource(stylesheet); 

 static CTOMath getOMML(String mathML) throws Exception {
  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;
 }

 public static void main(String[] args) throws Exception {

  XWPFDocument document = new XWPFDocument();

  XWPFParagraph paragraph = document.createParagraph();
  XWPFRun run = paragraph.createRun();
  run.setText("The Pythagorean theorem: ");

  String mathML = 
    "<math xmlns=\"http://www.w3.org/1998/Math/MathML\">" 
   +"<mrow>"
   +"<msup><mi>a</mi><mn>2</mn></msup><mo>+</mo><msup><mi>b</mi><mn>2</mn></msup><mo>=</mo><msup><mi>c</mi><mn>2</mn></msup>"
   +"</mrow>"
   +"</math>";

  CTOMath ctOMath = getOMML(mathML);
System.out.println(ctOMath);

  CTP ctp = paragraph.getCTP();
  ctp.setOMathArray(new CTOMath[]{ctOMath});

  paragraph = document.createParagraph();
  run = paragraph.createRun();
  run.setText("The Quadratic Formula: ");

  mathML = 
    "<math xmlns=\"http://www.w3.org/1998/Math/MathML\">"
   +"<mrow>" 
   +"<mi>x</mi><mo>=</mo><mfrac><mrow><mrow><mo>-</mo><mi>b</mi></mrow><mo>±</mo><msqrt><mrow><msup><mi>b</mi><mn>2</mn></msup><mo>-</mo><mrow><mn>4</mn><mo>⁢</mo><mi>a</mi><mo>⁢</mo><mi>c</mi></mrow></mrow></msqrt></mrow><mrow><mn>2</mn><mo>⁢</mo><mi>a</mi></mrow></mfrac>"
   +"</mrow>"
   +"</math>";

  ctOMath = getOMML(mathML);
System.out.println(ctOMath);

  ctp = paragraph.getCTP();
  ctp.setOMathArray(new CTOMath[]{ctOMath});
  
  FileOutputStream out = new FileOutputStream("CreateWordFormulaFromMathML.docx");
  document.write(out);
  out.close();
  document.close();

 }
}

请注意，此代码需要完整的 ooxml-schemas-*.jar 或 poi-ooxml-full-5.0.0.jar，如 https://poi.apache.org/faq.html#faq-N10025 中所述。 .

<小时/>

当然有 Java 库可用于将 LaTeX 转换为 MathML。例如:http://www.fmath.info/java/download.jsp .

已下载:fmath-mathml-java-test-project-b1124.zip 并具有 /lib/fmath-mathml-java.jar 和 /lib/jdom-2.0.6.jar 在类路径中，以下工作:

import java.io.*;
import org.apache.poi.xwpf.usermodel.*;

import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTP;
import org.openxmlformats.schemas.officeDocument.x2006.math.CTOMath;
import org.openxmlformats.schemas.officeDocument.x2006.math.CTOMathPara;
import org.openxmlformats.schemas.officeDocument.x2006.math.CTR;

import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.stream.StreamSource;
import javax.xml.transform.stream.StreamResult;

import org.apache.xmlbeans.XmlCursor;

/*
needs the full ooxml-schemas-1.3.jar as mentioned in https://poi.apache.org/faq.html#faq-N10025
*/

public class CreateWordFormulaFromLaTeX {

 static File stylesheet = new File("MML2OMML.XSL");
 static TransformerFactory tFactory = TransformerFactory.newInstance();
 static StreamSource stylesource = new StreamSource(stylesheet); 

 static CTOMath getOMML(String mathML) throws Exception {
  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");
    }
   }
  }

  return ctOMath;
 }

 public static void main(String[] args) throws Exception {

  XWPFDocument document = new XWPFDocument();

  XWPFParagraph paragraph = document.createParagraph();
  XWPFRun run = paragraph.createRun();
  run.setText("The Pythagorean theorem: ");

  String latex = "$a^2 + b^2 = c^2$";

  String mathML = fmath.conversion.ConvertFromLatexToMathML.convertToMathML(latex);
  mathML = mathML.replaceFirst("<math ", "<math xmlns=\"http://www.w3.org/1998/Math/MathML\" ");
System.out.println(mathML);

  CTOMath ctOMath = getOMML(mathML);
System.out.println(ctOMath);

  CTP ctp = paragraph.getCTP();
  ctp.setOMathArray(new CTOMath[]{ctOMath});


  paragraph = document.createParagraph();
  run = paragraph.createRun();
  run.setText("The Quadratic Formula: ");

  latex = "$x=\\frac{-b\\pm\\sqrt{b^2-4ac}}{2a}$";

  mathML = fmath.conversion.ConvertFromLatexToMathML.convertToMathML(latex);
  mathML = mathML.replaceFirst("<math ", "<math xmlns=\"http://www.w3.org/1998/Math/MathML\" ");
  mathML = mathML.replaceAll("&plusmn;", "±");
System.out.println(mathML);

  ctOMath = getOMML(mathML);
System.out.println(ctOMath);

  ctp = paragraph.getCTP();
  ctp.setOMathArray(new CTOMath[]{ctOMath});

  document.write(new FileOutputStream("CreateWordFormulaFromLaTeX.docx"));
  document.close();

 }
}

但是每次转换都可能存在错误。因此 LaTeX -> MathML -> OMML 比仅 MathML -> OMML 更容易出错。

在这种情况下，fmath.conversion.ConvertFromLatexToMathML.convertToMathML 会生成没有 namespace 的 Math XML。但由于 XSLT 需要这个，因此必须手动添加。

并且 fmath.conversion.ConvertFromLatexToMathML.convertToMathML 使用 HTML 实体，而 MML2OMML.XSL 不知道。因此示例中的“±”必须替换为“±”。

<小时/>

也许SnuggleTeX会是更好的图书馆吗？

下载它并在类路径中添加 snuggletex-core-1.2.2.jar ，我上一个示例中的以下代码更改有效:

...
  String latex = "$a^2 + b^2 = c^2$";

  uk.ac.ed.ph.snuggletex.SnuggleEngine engine = new uk.ac.ed.ph.snuggletex.SnuggleEngine();
  uk.ac.ed.ph.snuggletex.SnuggleSession session = engine.createSession();
  uk.ac.ed.ph.snuggletex.SnuggleInput input = new uk.ac.ed.ph.snuggletex.SnuggleInput(latex);
  session.parseInput(input);
  String mathML = session.buildXMLString();
System.out.println(mathML);

/*
  String mathML = fmath.conversion.ConvertFromLatexToMathML.convertToMathML(latex);
  mathML = mathML.replaceFirst("<math ", "<math xmlns=\"http://www.w3.org/1998/Math/MathML\" ");
System.out.println(mathML);
*/

  CTOMath ctOMath = getOMML(mathML);
System.out.println(ctOMath);

...

  latex = "$x=\\frac{-b\\pm\\sqrt{b^2-4ac}}{2a}$";

  engine = new uk.ac.ed.ph.snuggletex.SnuggleEngine();
  session = engine.createSession();
  input = new uk.ac.ed.ph.snuggletex.SnuggleInput(latex);
  session.parseInput(input);
  mathML = session.buildXMLString();
System.out.println(mathML);

/*
  mathML = fmath.conversion.ConvertFromLatexToMathML.convertToMathML(latex);
  mathML = mathML.replaceFirst("<math ", "<math xmlns=\"http://www.w3.org/1998/Math/MathML\" ");
  mathML = mathML.replaceAll("&plusmn;", "±");
System.out.println(mathML);
*/

  ctOMath = getOMML(mathML);
System.out.println(ctOMath);
...

无需手动干预。至少不使用给定的 LaTeX 示例。