如何使用 ZB713AE04A02A810D6F33DD956F42794Z POI 公式中的 excel 文本 function "NUMBERVALUE"

Question

I am using Apache POI to evaluate a formula cell that has a text function "NUMBERVALUE", then I got an exception Caused by: org.apache.poi.ss.formula.eval.NotImplementedFunctionException: _xlfn.NUMBERVALUE

有趣的是，当我尝试注册这个 function WorkbookEvaluator.registerFunction("NUMBERVALUE", new NumberRValue()); 它给了我另一个错误： java.lang.IllegalArgumentException: NUMBERVALUE is not a function 来自 Excel 分析工具包。

我还尝试通过实现 FreeRefFunction 来使用用户定义的函数，它又回到了第一个错误。

引起：org.apache.poi.ss.formula.eval.NotImplementedFunctionException: _xlfn.NUMBERVALUE

如何在 Apache POI 中实现文本 function？

Answer 1

WorkbookEvaluator.registerFunction仅适用于函数apache poi至少知道每个名称。 这是通过以下方式列出的所有功能：

java.util.Collection<String> unsupportedFuncs = org.apache.poi.ss.formula.WorkbookEvaluator.getNotSupportedFunctionNames();
System.out.println(unsupportedFuncs);

All the listed functions can be registered using WorkbookEvaluator.registerFunction either as org.apache.poi.hssf.record.formula.functions.Function , when in org.apache.poi.hssf.record.formula.atp.AnalysisToolPak or else as org.apache.poi.hssf.record.formula.functions.FreeRefFunction如果没有。

但NUMBERVALUE function 不在此列表中。 所以这只能作为用户定义的 function 添加。 请参阅apache poi文档的用户定义函数。

function 必须实现org.apache.poi.ss.formula.functions.FreeRefFunction并且必须在Workbook的 UDF 工具包中注册。

以下完整示例显示了_xlfn.NUMBERVALUE的基本实现。 使用NUMBERVALUE function中的描述完成实现。 到目前为止，它还是一个工作草案，可能需要改进以更好地实现与 Excel 自身结果的兼容性。

import java.io.FileInputStream;
import java.util.Locale;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.formula.functions.FreeRefFunction;
import org.apache.poi.ss.formula.udf.AggregatingUDFFinder;
import org.apache.poi.ss.formula.udf.DefaultUDFFinder;
import org.apache.poi.ss.formula.udf.UDFFinder;
import org.apache.poi.util.LocaleUtil;

public class EvaluateNUMBERVALUE {

 public static void main( String[] args ) throws Exception {
  Workbook workbook = WorkbookFactory.create(new FileInputStream("./ExcelWithNUMBERVALUE.xlsx"));    
  
  String[] functionNames = { "_xlfn.NUMBERVALUE" } ;
  FreeRefFunction[] functionImpls = { new NumberValue() } ;
  UDFFinder udfs = new DefaultUDFFinder( functionNames, functionImpls ) ;
  UDFFinder udfToolpack = new AggregatingUDFFinder( udfs ) ;    
  workbook.addToolPack(udfToolpack);
  
  LocaleUtil.setUserLocale(Locale.US);
  FormulaEvaluator formulaEvaluator = workbook.getCreationHelper().createFormulaEvaluator();
  
  DataFormatter dataFormatter = new DataFormatter();
  
  for (Sheet sheet: workbook) {
   for (Row row : sheet) {
    for (Cell cell : row) {
     String cellValue = dataFormatter.formatCellValue(cell, formulaEvaluator);
     System.out.println(cellValue);
    }
   }   
  }
 }
}

Class NumberValue在上面的代码中使用：

import java.lang.NumberFormatException;
import java.util.Locale;
import java.text.DecimalFormatSymbols;
import org.apache.poi.ss.formula.OperationEvaluationContext;
import org.apache.poi.ss.formula.eval.ValueEval;
import org.apache.poi.ss.formula.eval.NumberEval;
import org.apache.poi.ss.formula.eval.ErrorEval;
import org.apache.poi.ss.formula.eval.EvaluationException;
import org.apache.poi.ss.formula.eval.OperandResolver;
import org.apache.poi.ss.formula.functions.FreeRefFunction;
import org.apache.poi.util.LocaleUtil;


public final class NumberValue implements FreeRefFunction  {
 @Override
 public ValueEval evaluate( ValueEval[] args, OperationEvaluationContext ec ) {
     
  Locale locale = LocaleUtil.getUserLocale();
  DecimalFormatSymbols decimalFormatSymbols = new DecimalFormatSymbols(locale);
  
  String text = null;
  //If the Decimal_separator and Group_separator arguments are not specified, separators from the current locale are used.
  String decSep = String.valueOf(decimalFormatSymbols.getDecimalSeparator());
  String groupSep = String.valueOf(decimalFormatSymbols.getGroupingSeparator());

  Double result = Double.NaN;
  ValueEval v1 = null;
  ValueEval v2 = null;
  ValueEval v3 = null;
  
  try {
   if (args.length == 1) {  
    v1 = OperandResolver.getSingleValue( args[0], ec.getRowIndex(), ec.getColumnIndex());
    text = OperandResolver.coerceValueToString(v1);
   } else if (args.length == 2) { 
    v1 = OperandResolver.getSingleValue( args[0], ec.getRowIndex(), ec.getColumnIndex());
    v2 = OperandResolver.getSingleValue( args[1], ec.getRowIndex(), ec.getColumnIndex());
    text = OperandResolver.coerceValueToString(v1);
    decSep = OperandResolver.coerceValueToString(v2).substring(0, 1); //If multiple characters are used in the Decimal_separator or Group_separator arguments, only the first character is used.
   } else if (args.length == 3) { 
    v1 = OperandResolver.getSingleValue( args[0], ec.getRowIndex(), ec.getColumnIndex());
    v2 = OperandResolver.getSingleValue( args[1], ec.getRowIndex(), ec.getColumnIndex());
    v3 = OperandResolver.getSingleValue( args[2], ec.getRowIndex(), ec.getColumnIndex());
    text = OperandResolver.coerceValueToString(v1);
    decSep = OperandResolver.coerceValueToString(v2).substring(0, 1); //If multiple characters are used in the Decimal_separator or Group_separator arguments, only the first character is used.
    groupSep = OperandResolver.coerceValueToString(v3).substring(0, 1); //If multiple characters are used in the Decimal_separator or Group_separator arguments, only the first character is used.
   }
  } catch (EvaluationException e) {
   e.printStackTrace() ;
   return e.getErrorEval();
  }  
  
  if("".equals(text)) text = "0"; //If an empty string ("") is specified as the Text argument, the result is 0.
  text = text.replace(" ", ""); //Empty spaces in the Text argument are ignored, even in the middle of the argument. For example, " 3 000 " is returned as 3000.
  String[] parts = text.split("["+decSep+"]");
  String sigPart = "";
  String decPart = "";
  if (parts.length > 2) return ErrorEval.VALUE_INVALID; //If a decimal separator is used more than once in the Text argument, NUMBERVALUE returns the #VALUE! error value.
  if (parts.length > 1) {
   sigPart = parts[0];
   decPart = parts[1];
   if (decPart.contains(groupSep)) return ErrorEval.VALUE_INVALID; //If the group separator occurs after the decimal separator in the Text argument, NUMBERVALUE returns the #VALUE! error value.
   sigPart = sigPart.replace(groupSep, ""); //If the group separator occurs before the decimal separator in the Text argument , the group separator is ignored.
   text = sigPart + "." + decPart;
  } else if (parts.length > 0) {
   sigPart = parts[0];
   sigPart = sigPart.replace(groupSep, ""); //If the group separator occurs before the decimal separator in the Text argument , the group separator is ignored.
   text = sigPart;
  } 
  
  //If the Text argument ends in one or more percent signs (%), they are used in the calculation of the result. 
  //Multiple percent signs are additive if they are used in the Text argument just as they are if they are used in a formula. 
  //For example, =NUMBERVALUE("9%%") returns the same result (0.0009) as the formula =9%%.
  int countPercent = 0;
  while (text.endsWith("%")) {
   countPercent++;
   text = text.substring(0, text.length()-1);   
  }
    
  try {  
   result = Double.valueOf(text);
   result = result / Math.pow(100, countPercent); //If the Text argument ends in one or more percent signs (%), they are used in the calculation of the result. 
   checkValue(result);
  } catch (EvaluationException e) {
    e.printStackTrace() ;
    return e.getErrorEval();
  } catch (Exception anyex) {
    return ErrorEval.VALUE_INVALID; //If any of the arguments are not valid, NUMBERVALUE returns the #VALUE! error value.
  }
  
  return new NumberEval(result);
 
 }
 
 static final void checkValue(double result) throws EvaluationException {
  if (Double.isNaN(result) || Double.isInfinite(result)) {
   throw new EvaluationException(ErrorEval.NUM_ERROR);
  }
 }
}

前缀_xlfn. ?

Excel 使用它来标记在 Excel 2007 之后引入的功能。前缀存储为 function 名称的一部分。 If the Excel version knows that function because it is later than Excel 2007, then the GUI will not show that prefix and evaluates the function. 如果 Excel 版本不知道 function，则 GUI 将显示前缀以通知用户该不兼容。 请参阅问题：一个 _xlfn。 前缀显示在公式前面

由于存储了前缀，用户定义 function 必须注册为 function 名称，包括前缀： String[] functionNames = { "_xlfn.NUMBERVALUE" }; .

---

此代码是公开的。 它可以在任何类型的项目中免费重用。 当然，我这边没有任何保证。