java使用Apache POI API将xlsx转换为csv

Question

我正在尝试转换。xlsx文件到。csv，正在进行转换，但数据格式不正确。请查找下面的代码，并建议对代码进行更改

在这里，我试图阅读一篇。xlsx文件并将其写入csv文件，即将xlsx转换为csv，但我没有得到。csv文件格式正确所有数据都显示在一个单独的文件中，但必须像Excel中的行一样显示

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Iterator;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class XlsxtoCSV {

    static void xlsx(File inputFile, File outputFile) {
        // For storing data into CSV files
        StringBuffer data = new StringBuffer();

        try {
            FileOutputStream fos = new FileOutputStream(outputFile);
            // Get the workbook object for XLSX file
            XSSFWorkbook wBook = new XSSFWorkbook(new FileInputStream(inputFile));
            // Get first sheet from the workbook
            XSSFSheet sheet = wBook.getSheetAt(0);
            Row row;
            Cell cell;
            // Iterate through each rows from first sheet
            Iterator<Row> rowIterator = sheet.iterator();

            while (rowIterator.hasNext()) {
                row = rowIterator.next();

                // For each row, iterate through each columns
                Iterator<Cell> cellIterator = row.cellIterator();
                while (cellIterator.hasNext()) {

                    cell = cellIterator.next();

                    switch (cell.getCellType()) {
                        case Cell.CELL_TYPE_BOOLEAN:
                            data.append(cell.getBooleanCellValue() + ",");

                            break;
                        case Cell.CELL_TYPE_NUMERIC:
                            data.append(cell.getNumericCellValue() + ",");

                            break;
                        case Cell.CELL_TYPE_STRING:
                            data.append(cell.getStringCellValue() + ",");
                            break;

                        case Cell.CELL_TYPE_BLANK:
                            data.append("" + ",");
                            break;
                        default:
                            data.append(cell + ",");

                    }
                }
            }

            fos.write(data.toString().getBytes());
            fos.close();

        } catch (Exception ioe) {
            ioe.printStackTrace();
        }
    }
    //testing the application 

    public static void main(String[] args) {
        //reading file from desktop
        File inputFile = new File("C:\\Users\\user69\\Desktop\\test.xlsx");
        //writing excel data to csv 
        File outputFile = new File("C:\\Users\\user69\\Desktop\\test1.csv");
        xlsx(inputFile, outputFile);
    }
}

Answer 1

使用Commons CSV对单元格值进行编码，这样更健壮。不幸的是，仍然需要一些额外的代码来逐行/单元格地遍历工作表，并在每个单元格上调用Commons CSV（XSSF不提供这一点），但至少要保证编写的实际单元格值是标准CSV（即，您不必担心转义字符或添加逗号）

Maven为Commons CSV添加：

<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-csv</artifactId>
            <version>1.5</version>
        </dependency>   

一旦Commons CSV可用，这就是将工作簿导出到CSV的代码。此示例写入OutputStream，但文件输出也很容易

// Convert an XSSFWorkbook to CSV and write to provided OutputStream
private void writeWorkbookAsCSVToOutputStream(XSSFWorkbook workbook, OutputStream out) {        
    CSVPrinter csvPrinter = null;       
    try {       
        csvPrinter = new CSVPrinter(new OutputStreamWriter(out), CSVFormat.DEFAULT);                

        if (workbook != null) {
            XSSFSheet sheet = workbook.getSheetAt(0); // Sheet #0 in this example
            Iterator<Row> rowIterator = sheet.rowIterator();
            while (rowIterator.hasNext()) {               
                Row row = rowIterator.next();
                Iterator<Cell> cellIterator = row.cellIterator();
                while (cellIterator.hasNext()) {
                    Cell cell = cellIterator.next();
                    csvPrinter.print(cell.getStringCellValue());
                }                   
                csvPrinter.println(); // Newline after each row
            }               
        }

    }
    catch (Exception e) {
        log.error("Failed to write CSV file to output stream", e);
    }
    finally {
        try {
            if (csvPrinter != null) {
                csvPrinter.flush(); // Flush and close CSVPrinter
                csvPrinter.close();
            }
        }
        catch (IOException ioe) {
            log.error("Error when closing CSV Printer", ioe);
        }           
    }
}   

Answer 2

这是感谢@Swapnil

data.append("\r\n"); // After the columns have been appended.

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以下内容由@Abdullah编辑（添加） 我在上面最初的回答没有那么大的影响，但阿卜杜拉的编辑显示了很大的努力，所以我把它留给那些遇到这个问题的人&；回答

public class App {

    public void convertExcelToCSV(Sheet sheet, String sheetName) {
        StringBuilder data = new StringBuilder();
        try {
            Iterator<Row> rowIterator = sheet.iterator();
            while (rowIterator.hasNext()) {
                Row row = rowIterator.next();
                Iterator<Cell> cellIterator = row.cellIterator();
                while (cellIterator.hasNext()) {
                    Cell cell = cellIterator.next();

                    CellType type = cell.getCellTypeEnum();
                    if (type == CellType.BOOLEAN) {
                        data.append(cell.getBooleanCellValue());
                    } else if (type == CellType.NUMERIC) {
                        data.append(cell.getNumericCellValue());
                    } else if (type == CellType.STRING) {
                        String cellValue = cell.getStringCellValue();
                        if(!cellValue.isEmpty()) {
                            cellValue = cellValue.replaceAll("\"", "\"\"");
                            data.append("\"").append(cellValue).append("\"");
                        }
                    } else if (type == CellType.BLANK) {
                    } else {
                        data.append(cell + "");
                    }
                    if(cell.getColumnIndex() != row.getLastCellNum()-1) {
                        data.append(",");
                    }
                }
                data.append('\n');
            }
            Files.write(Paths.get("C:\\Users\\" + sheetName + ".csv"),
                data.toString().getBytes("UTF-8"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String [] args)
    {
        App app = new App();
        String path =  "C:\\Users\\myFile.xlsx";
        try (InputStream inp = new FileInputStream(path)) {
            Workbook wb = WorkbookFactory.create(inp);

            for (int i = 0; i < wb.getNumberOfSheets(); i++) {
                System.out.println(wb.getSheetAt(i).getSheetName());
                app.convertExcelToCSV(wb.getSheetAt(i), wb.getSheetAt(i).getSheetName());
            }
        } catch (Exception ex) {
            System.out.println(ex.getMessage());
        } 
    }
}

Answer 3

public static void convertToXlsx(File inputFile, File outputFile) {
StringBuffer bf = new StringBuffer();
    FileOutputStream fos = null;
    String strGetValue = "";
    try {
        fos = new FileOutputStream(outputFile);
        XSSFWorkbook wb = new XSSFWorkbook(new FileInputStream(inputFile));
        XSSFSheet sheet = wb.getSheetAt(0);
        Row row;
        Cell cell;
        int intRowCounter = 0;
        Iterator<Row> rowIterator = sheet.iterator();
        while (rowIterator.hasNext()) {
            StringBuffer cellDData = new StringBuffer();
            row = rowIterator.next();
            int maxNumOfCells = sheet.getRow(0).getLastCellNum();
            int cellCounter = 0;
            while ((cellCounter) < maxNumOfCells) {
                if (sheet.getRow(row.getRowNum()) != null
                        && sheet.getRow(row.getRowNum()).getCell(cellCounter) != null) {
                    cell = sheet.getRow(row.getRowNum()).getCell(cellCounter);
                    switch (cell.getCellType()) {
                    case Cell.CELL_TYPE_BOOLEAN:
                        strGetValue = cell.getBooleanCellValue() + ",";
                        cellDData.append(removeSpace(strGetValue));
                        break;
                    case Cell.CELL_TYPE_NUMERIC:
                        strGetValue = new BigDecimal(cell.getNumericCellValue()).toPlainString();
                        if (DateUtil.isCellDateFormatted(cell)) {
                            strGetValue = new DataFormatter().formatCellValue(cell);
                        } else {
                            strGetValue = new BigDecimal(cell.getNumericCellValue()).toPlainString();
                        }
                        String tempStrGetValue = removeSpace(strGetValue);
                        if (tempStrGetValue.length() == 0) {
                            strGetValue = " ,";
                            cellDData.append(strGetValue);
                        } else {
                            strGetValue = strGetValue + ",";
                            cellDData.append(removeSpace(strGetValue));
                        }
                        break;
                    case Cell.CELL_TYPE_STRING:
                        strGetValue = cell.getStringCellValue();
                        String tempStrGetValue1 = removeSpace(strGetValue);
                        if (tempStrGetValue1.length() == 0) {
                            strGetValue = " ,";
                            cellDData.append(strGetValue);
                        } else {
                            strGetValue = strGetValue + ",";
                            cellDData.append(removeSpace(strGetValue));
                        }
                        break;
                    case Cell.CELL_TYPE_BLANK:
                        strGetValue = "" + ",";
                        cellDData.append(removeSpace(strGetValue));
                        break;
                    default:
                        strGetValue = cell + ",";
                        cellDData.append(removeSpace(strGetValue));
                    }
                } else {
                    strGetValue = " ,";
                    cellDData.append(strGetValue);
                }
                cellCounter++;
            }
            String temp = cellDData.toString();
            if (temp != null && temp.contains(",,,")) {
                temp = temp.replaceFirst(",,,", ", ,");
            }
            if (temp.endsWith(",")) {
                temp = temp.substring(0, temp.lastIndexOf(","));
                cellDData = null;
                bf.append(temp.trim());
            }
            bf.append("\n");
            intRowCounter++;
        }
        fos.write(bf.toString().getBytes());
        fos.close();
    } catch (Exception ex) {
        ex.printStackTrace();
    } finally {
        try {
            if (fos != null)
                fos.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}
private static String removeSpace(String strString) {
    if (strString != null && !strString.equals("")) {
        return strString.trim();
    }
    return strString;
}

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1. 代码示例句柄和单元格中的空格字符

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