NPOI 导出表格无法自动计算解决

1，设置sheet.ForceFormulaRecalculation = true;

2，

如果你的浏览器对文件进行读写保护时也无法计算出结果，更改浏览器或者打开时启动编辑就行。

附上标准的NPOI操作程序

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   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
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   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
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package org.apache.poi.ss.examples;

import org.apache.poi.xssf.usermodel.*;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import java.util.Map;
import java.util.HashMap;
import java.io.FileOutputStream;

/**
 * Simple Loan Calculator. Demonstrates advance usage of cell formulas and named ranges.
 *
 * Usage:
 *   LoanCalculator -xls|xlsx
 *
 * @author Yegor Kozlov
 */
public class LoanCalculator {

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

        if(args.length > 0 && args[0].equals("-xls")) wb = new HSSFWorkbook();
        else wb = new XSSFWorkbook();

        Map<String, CellStyle> styles = createStyles(wb);
        Sheet sheet = wb.createSheet("Loan Calculator");
        sheet.setPrintGridlines(false);
        sheet.setDisplayGridlines(false);

        PrintSetup printSetup = sheet.getPrintSetup();
        printSetup.setLandscape(true);
        sheet.setFitToPage(true);
        sheet.setHorizontallyCenter(true);

        sheet.setColumnWidth(0, 3*256);
        sheet.setColumnWidth(1, 3*256);
        sheet.setColumnWidth(2, 11*256);
        sheet.setColumnWidth(3, 14*256);
        sheet.setColumnWidth(4, 14*256);
        sheet.setColumnWidth(5, 14*256);
        sheet.setColumnWidth(6, 14*256);

        createNames(wb);

        Row titleRow = sheet.createRow(0);
        titleRow.setHeightInPoints(35);
        for (int i = 1; i <= 7; i++) {
            titleRow.createCell(i).setCellStyle(styles.get("title"));
        }
        Cell titleCell = titleRow.getCell(2);
        titleCell.setCellValue("Simple Loan Calculator");
        sheet.addMergedRegion(CellRangeAddress.valueOf("$C$1:$H$1"));

        Row row = sheet.createRow(2);
        Cell cell = row.createCell(4);
        cell.setCellValue("Enter values");
        cell.setCellStyle(styles.get("item_right"));

        row = sheet.createRow(3);
        cell = row.createCell(2);
        cell.setCellValue("Loan amount");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellStyle(styles.get("input_$"));
        cell.setAsActiveCell();

        row = sheet.createRow(4);
        cell = row.createCell(2);
        cell.setCellValue("Annual interest rate");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellStyle(styles.get("input_%"));

        row = sheet.createRow(5);
        cell = row.createCell(2);
        cell.setCellValue("Loan period in years");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellStyle(styles.get("input_i"));

        row = sheet.createRow(6);
        cell = row.createCell(2);
        cell.setCellValue("Start date of loan");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellStyle(styles.get("input_d"));

        row = sheet.createRow(8);
        cell = row.createCell(2);
        cell.setCellValue("Monthly payment");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellFormula("IF(Values_Entered,Monthly_Payment,"")");
        cell.setCellStyle(styles.get("formula_$"));

        row = sheet.createRow(9);
        cell = row.createCell(2);
        cell.setCellValue("Number of payments");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellFormula("IF(Values_Entered,Loan_Years*12,"")");
        cell.setCellStyle(styles.get("formula_i"));

        row = sheet.createRow(10);
        cell = row.createCell(2);
        cell.setCellValue("Total interest");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellFormula("IF(Values_Entered,Total_Cost-Loan_Amount,"")");
        cell.setCellStyle(styles.get("formula_$"));

        row = sheet.createRow(11);
        cell = row.createCell(2);
        cell.setCellValue("Total cost of loan");
        cell.setCellStyle(styles.get("item_left"));
        cell = row.createCell(4);
        cell.setCellFormula("IF(Values_Entered,Monthly_Payment*Number_of_Payments,"")");
        cell.setCellStyle(styles.get("formula_$"));


        // Write the output to a file
        String file = "loan-calculator.xls";
        if(wb instanceof XSSFWorkbook) file += "x";
        FileOutputStream out = new FileOutputStream(file);
        wb.write(out);
        out.close();
    }

    /**
     * cell styles used for formatting calendar sheets
     */
    private static Map<String, CellStyle> createStyles(Workbook wb){
        Map<String, CellStyle> styles = new HashMap<>();

        CellStyle style;
        Font titleFont = wb.createFont();
        titleFont.setFontHeightInPoints((short)14);
        titleFont.setFontName("Trebuchet MS");
        style = wb.createCellStyle();
        style.setFont(titleFont);
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        styles.put("title", style);

        Font itemFont = wb.createFont();
        itemFont.setFontHeightInPoints((short)9);
        itemFont.setFontName("Trebuchet MS");
        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.LEFT);
        style.setFont(itemFont);
        styles.put("item_left", style);

        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.RIGHT);
        style.setFont(itemFont);
        styles.put("item_right", style);

        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.RIGHT);
        style.setFont(itemFont);
        style.setBorderRight(BorderStyle.DOTTED);
        style.setRightBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderLeft(BorderStyle.DOTTED);
        style.setLeftBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderTop(BorderStyle.DOTTED);
        style.setTopBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setDataFormat(wb.createDataFormat().getFormat("_($* #,##0.00_);_($* (#,##0.00);_($* "-"??_);_(@_)"));
        styles.put("input_$", style);

        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.RIGHT);
        style.setFont(itemFont);
        style.setBorderRight(BorderStyle.DOTTED);
        style.setRightBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderLeft(BorderStyle.DOTTED);
        style.setLeftBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderTop(BorderStyle.DOTTED);
        style.setTopBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setDataFormat(wb.createDataFormat().getFormat("0.000%"));
        styles.put("input_%", style);

        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.RIGHT);
        style.setFont(itemFont);
        style.setBorderRight(BorderStyle.DOTTED);
        style.setRightBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderLeft(BorderStyle.DOTTED);
        style.setLeftBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderTop(BorderStyle.DOTTED);
        style.setTopBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setDataFormat(wb.createDataFormat().getFormat("0"));
        styles.put("input_i", style);

        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.CENTER);
        style.setFont(itemFont);
        style.setDataFormat(wb.createDataFormat().getFormat("m/d/yy"));
        styles.put("input_d", style);

        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.RIGHT);
        style.setFont(itemFont);
        style.setBorderRight(BorderStyle.DOTTED);
        style.setRightBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderLeft(BorderStyle.DOTTED);
        style.setLeftBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderTop(BorderStyle.DOTTED);
        style.setTopBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setDataFormat(wb.createDataFormat().getFormat("$##,##0.00"));
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
        style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        styles.put("formula_$", style);

        style = wb.createCellStyle();
        style.setAlignment(HorizontalAlignment.RIGHT);
        style.setFont(itemFont);
        style.setBorderRight(BorderStyle.DOTTED);
        style.setRightBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderLeft(BorderStyle.DOTTED);
        style.setLeftBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setBorderTop(BorderStyle.DOTTED);
        style.setTopBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setDataFormat(wb.createDataFormat().getFormat("0"));
        style.setBorderBottom(BorderStyle.DOTTED);
        style.setBottomBorderColor(IndexedColors.GREY_40_PERCENT.getIndex());
        style.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.getIndex());
        style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        styles.put("formula_i", style);

        return styles;
    }

    //define named ranges for the inputs and formulas
    public static void createNames(Workbook wb){
        Name name;

        name = wb.createName();
        name.setNameName("Interest_Rate");
        name.setRefersToFormula("'Loan Calculator'!$E$5");

        name = wb.createName();
        name.setNameName("Loan_Amount");
        name.setRefersToFormula("'Loan Calculator'!$E$4");

        name = wb.createName();
        name.setNameName("Loan_Start");
        name.setRefersToFormula("'Loan Calculator'!$E$7");

        name = wb.createName();
        name.setNameName("Loan_Years");
        name.setRefersToFormula("'Loan Calculator'!$E$6");

        name = wb.createName();
        name.setNameName("Number_of_Payments");
        name.setRefersToFormula("'Loan Calculator'!$E$10");

        name = wb.createName();
        name.setNameName("Monthly_Payment");
        name.setRefersToFormula("-PMT(Interest_Rate/12,Number_of_Payments,Loan_Amount)");

        name = wb.createName();
        name.setNameName("Total_Cost");
        name.setRefersToFormula("'Loan Calculator'!$E$12");

        name = wb.createName();
        name.setNameName("Total_Interest");
        name.setRefersToFormula("'Loan Calculator'!$E$11");

        name = wb.createName();
        name.setNameName("Values_Entered");
        name.setRefersToFormula("IF(Loan_Amount*Interest_Rate*Loan_Years*Loan_Start>0,1,0)");
    }
}