问题

以下是你的代码的中文翻译部分：

我目前正在尝试编写一个可以更好地组织你的工作时间的程序。因此，我使用Apache POI来创建一个Excel文件。我已经相对进展较多，但在某一点上无法继续前进。我的问题是，你每天输入工时，程序将其写入相应的Excel文件。但是，如果我想输入下一天，程序会覆盖Excel文件并删除前一天的内容。
所以我的问题是我不知道如何在下面的行中写入数据。
我已经尝试过FileInputStream，但因为我每个月都创建一个新文件，所以它并没有真正起作用。

这是我用于创建和写入Excel文件的代码。

public void speichern(ActionEvent event) throws Exception {

    LocalDate localDate = date.getValue();
    datum = String.valueOf(localDate);

    do {
        if(btnNextMon.isArmed()){
            monClick++;
            System.out.println(monClick);
        }
        if (btnSave.isArmed()){
            saveClick++;
        }

        try {
            XSSFWorkbook workbook = new XSSFWorkbook();
            XSSFSheet sheet = workbook.createSheet("Stundenabrechnung");
            sheet.setDefaultColumnWidth(18);

            Map<String, Object[]> data = new TreeMap<>();
            data.put("1", new Object[]{"DATUM:", " INS. ABG. STUNDEN:", " ABGR. STUNDEN:", " BESCHREIBUNG:"});
            data.put("2", new Object[]{datum, ergbnis + "0", LHabg.getText(), taBes.getText()});

            Set<String> keyset = data.keySet();
            int rownum = 0;
            for (String key : keyset) {
                XSSFRow row = sheet.createRow(rownum++);
                Object[] objArr = data.get(key);
                int cellnum = 0;
                for (Object obj : objArr) {
                    XSSFCell cell = row.createCell(cellnum++);
                    CellStyle cellStyle = workbook.createCellStyle();
                    cellStyle.setAlignment(HorizontalAlignment.CENTER);
                    cellStyle.setVerticalAlignment(VerticalAlignment.TOP);
                    cell.setCellStyle(cellStyle);
                    if (obj instanceof String) {
                        cell.setCellValue((String) obj);
                    } else if (obj instanceof Integer) {
                        cell.setCellValue((Integer) obj);
                    }
                }
            }
            FileOutputStream outputStream = new FileOutputStream("Stundenabrechnung" + monClick + ".xlsx");
            workbook.write(outputStream);
            workbook.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
        System.out.println("ExcelFile is created succsessfully");
    } while (btnNextMon.isPressed());
}

希望这对你有所帮助！

英文:

I am currently trying to write a program that can better organize your working hours. So I use Apache POI to create an Excel file. I'm already relatively far, but I can't get any further at one point. My problem is that you enter your hours per day and the program writes them in the corresponding Excel file. However, if I want to enter the next day, the program overwrites the Excel file and the previous day is deleted.
So my problem is that I don't know how to write in the rows underneath.
I've already tried FileInputStream, but it didn't really work because I create a new file every month.

This is my code for creating and writing the Excel file.

public void speichern(ActionEvent event) throws Exception {
LocalDate localDate = date.getValue();
datum = String.valueOf(localDate);
do {
if(btnNextMon.isArmed()){
monClick++;
System.out.println(monClick);
}
if (btnSave.isArmed()){
saveClick++;
}
try {
XSSFWorkbook workbook = new XSSFWorkbook();
XSSFSheet sheet = workbook.createSheet(&quot;Stundenabrechnung&quot;);
sheet.setDefaultColumnWidth(18);
Map&lt;String, Object[]&gt; data = new TreeMap&lt;&gt;();
data.put(&quot;1&quot;, new Object[]{&quot;DATUM:&quot;, &quot; INS. ABG. STUNDEN:&quot;, &quot; ABGR. STUNDEN:&quot;, &quot; BESCHREIBUNG:&quot;});
data.put(&quot;2&quot;, new Object[]{datum, ergbnis + &quot;0&quot;, LHabg.getText(), taBes.getText()});
Set&lt;String&gt; keyset = data.keySet();
int rownum = 0;
for (String key : keyset) {
XSSFRow row = sheet.createRow(rownum++);
Object[] objArr = data.get(key);
int cellnum = 0;
for (Object obj : objArr) {
XSSFCell cell = row.createCell(cellnum++);
CellStyle cellStyle = workbook.createCellStyle();
cellStyle.setAlignment(HorizontalAlignment.CENTER);
cellStyle.setVerticalAlignment(VerticalAlignment.TOP);
cell.setCellStyle(cellStyle);
if (obj instanceof String) {
cell.setCellValue((String) obj);
} else if (obj instanceof Integer) {
cell.setCellValue((Integer) obj);
}
}
}
FileOutputStream outputStream = new FileOutputStream(&quot;Stundenabrechnung&quot; + monClick +&quot;.xlsx&quot;);
workbook.write(outputStream);
workbook.close();
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(&quot;ExcelFile is created succsessfully&quot;);
}while (btnNextMon.isPressed());
}

thanks for the help

答案1

得分: 1

我认为在创建新的书和电子表格之前，你应该检查文件是否已经存在。

你可以使用类似以下的代码：

编辑： 我已经更改了引发问题的那一行

try {
    boolean fileExists = new File("Stundenabrechnung" + monClick + ".xlsx").exists();
    XSSFWorkbook workbook;
    XSSFSheet sheet;
    if (fileExists) {
        workbook = new XSSFWorkbook(new FileInputStream(new File("Stundenabrechnung" + monClick + ".xlsx")));
        sheet = workbook.getSheetAt(0);

        Map<String, Object[]> data = new TreeMap<>();
        data.put("3", new Object[]{datum, ergbnis + "0", LHabg.getText(), taBes.getText()});

        Set<String> keyset = data.keySet();
        int rownum = sheet.getLastRowNum() + 1;
        for (String key : keyset) {
            XSSFRow row = sheet.createRow(rownum++);
            Object[] objArr = data.get(key);
            int cellnum = 0;
            for (Object obj : objArr) {

                XSSFCell cell = row.createCell(cellnum++);
                CellStyle cellStyle = workbook.createCellStyle();
                cellStyle.setAlignment(HorizontalAlignment.CENTER);
                cellStyle.setVerticalAlignment(VerticalAlignment.TOP);
                cell.setCellStyle(cellStyle);
                if (obj instanceof String) {
                    cell.setCellValue((String) obj);
                } else if (obj instanceof Integer) {
                    cell.setCellValue((Integer) obj);
                }
            }
        }
    } else {
        workbook = new XSSFWorkbook();
        sheet = workbook.createSheet("Stundenabrechnung");
        sheet.setDefaultColumnWidth(18);

        Map<String, Object[]> data = new TreeMap<>();
        data.put("1", new Object[]{"DATUM:", " INS. ABG. STUNDEN:", " ABGR. STUNDEN:", " BESCHREIBUNG:"});
        data.put("2", new Object[]{datum, ergbnis + "0", LHabg.getText(), taBes.getText()});

        Set<String> keyset = data.keySet();
        int rownum = 0;
        for (String key : keyset) {
            XSSFRow row = sheet.createRow(rownum++);
            Object[] objArr = data.get(key);
            int cellnum = 0;
            for (Object obj : objArr) {

                XSSFCell cell = row.createCell(cellnum++);
                CellStyle cellStyle = workbook.createCellStyle();
                cellStyle.setAlignment(HorizontalAlignment.CENTER);
                cellStyle.setVerticalAlignment(VerticalAlignment.TOP);
                cell.setCellStyle(cellStyle);
                if (obj instanceof String) {
                    cell.setCellValue((String) obj);
                } else if (obj instanceof Integer) {
                    cell.setCellValue((Integer) obj);
                }
            }
        }
    }
    FileOutputStream outputStream = new FileOutputStream("Stundenabrechnung" + monClick + ".xlsx");
    workbook.write(outputStream);
    workbook.close();

} catch (Exception e) {
    e.printStackTrace();
}

英文:

I think you should check if the file already exists before creating a new book and spreadsheet

You could use something like:

EDIT: I changed the line that was causing the problem

 try {
boolean fileExists = new File(&quot;Stundenabrechnung&quot; + monClick +&quot;.xlsx&quot;).exists();
XSSFWorkbook workbook;
XSSFSheet sheet;
if (fileExists) {
workbook = new XSSFWorkbook(new FileInputStream(new File(&quot;Stundenabrechnung&quot; + monClick +&quot;.xlsx&quot;)));
sheet = workbook.getSheetAt(0);
Map&lt;String, Object[]&gt; data = new TreeMap&lt;&gt;();
data.put(&quot;3&quot;, new Object[]{datum, ergbnis + &quot;0&quot;, LHabg.getText(), taBes.getText()});
Set&lt;String&gt; keyset = data.keySet();
int rownum = sheet.getLastRowNum() + 1;             
for (String key : keyset) {
XSSFRow row = sheet.createRow(rownum++);
Object[] objArr = data.get(key);
int cellnum = 0;
for (Object obj : objArr) {
XSSFCell cell = row.createCell(cellnum++);
CellStyle cellStyle = workbook.createCellStyle();
cellStyle.setAlignment(HorizontalAlignment.CENTER);
cellStyle.setVerticalAlignment(VerticalAlignment.TOP);
cell.setCellStyle(cellStyle);
if (obj instanceof String) {
cell.setCellValue((String) obj);
} else if (obj instanceof Integer) {
cell.setCellValue((Integer) obj);
}
}
}
} else {
workbook = new XSSFWorkbook();
sheet = workbook.createSheet(&quot;Stundenabrechnung&quot;);
sheet.setDefaultColumnWidth(18);
Map&lt;String, Object[]&gt; data = new TreeMap&lt;&gt;();
data.put(&quot;1&quot;, new Object[]{&quot;DATUM:&quot;, &quot; INS. ABG. STUNDEN:&quot;, &quot; ABGR. STUNDEN:&quot;, &quot; BESCHREIBUNG:&quot;});
data.put(&quot;2&quot;, new Object[]{datum, ergbnis + &quot;0&quot;, LHabg.getText(), taBes.getText()});
Set&lt;String&gt; keyset = data.keySet();
int rownum = 0;
for (String key : keyset) {
XSSFRow row = sheet.createRow(rownum++);
Object[] objArr = data.get(key);
int cellnum = 0;
for (Object obj : objArr) {
XSSFCell cell = row.createCell(cellnum++);
CellStyle cellStyle = workbook.createCellStyle();
cellStyle.setAlignment(HorizontalAlignment.CENTER);
cellStyle.setVerticalAlignment(VerticalAlignment.TOP);
cell.setCellStyle(cellStyle);
if (obj instanceof String) {
cell.setCellValue((String) obj);
} else if (obj instanceof Integer) {
cell.setCellValue((Integer) obj);
}
}
}
}
FileOutputStream outputStream = new FileOutputStream(&quot;Stundenabrechnung&quot; + monClick +&quot;.xlsx&quot;);
workbook.write(outputStream);
workbook.close();
} catch (Exception e) {
e.printStackTrace();
}

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Apache POI / 一键在Excel中插入新行

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