java - 使用 jxl 修改现有的 excel

Question

我无法使用 jxl 编辑现有的 excel 工作表。它总是创造一个新的。任何人都可以帮我解决它。请给出一个小示例代码。

Answer 1

jxl 旨在提高读取效率（因为这是 API 的主要用途）。为了提高性能，与输出信息相关的数据（例如，所有格式信息，如字体）在读取电子表格时不会被解释，因为在询问原始数据值时这是多余的。

但是，如果我们需要修改此电子表格，则需要各种写入接口的句柄，可以使用 copy 方法获得。

Workbook workbook = Workbook.getWorkbook(new File("myfile.xls"));
WritableWorkbook copy = Workbook.createWorkbook(new File("temp.xls"), workbook);

这会复制已读入的信息，并执行附加处理以解释编写电子表格所需的字段。这种读取优化策略的缺点是我们在内存中保存了两个电子表格，而不仅仅是一个，因此内存需求增加了一倍。

但在这之后，你可以为所欲为。喜欢：

WritableSheet sheet2 = copy.getSheet(1); 
WritableCell cell = sheet2.getWritableCell(1, 2); 

if (cell.getType() == CellType.LABEL) 
{ 
  Label l = (Label) cell; 
  l.setString("modified cell"); 
}
copy.write(); 
copy.close();
workbook.close();

注意：这是直接取自Andy Khan 的教程页面。

Answer 2

我知道这是一个很老的问题，但如果有人会遇到同样的问题，那么为了保留正确的格式（字体类型、颜色等），您应该在将单元格格式转换为标签之前保存单元格格式，然后强制单元格到以前的格式。代码：

CellFormat cfm = cell.getCellFormat();
Label l = (Label) cell; 
l.setString("modified cell");
cell.setCellFormat(cfm);

Answer 3

//there is god example of it, you can copy in ur project and check it out, to 
//understand how  it works

Workbook wk = Workbook.getWorkbook(new File("ex.xls"));
// 
WritableWorkbook wkr = Workbook.createWorkbook(new File("modifed.xls"), wk);
/* second line makes copy of wk excel file object /creates a readable spreadsheet.
both are now similar and i can Modify exiting wkr spreadsheets */



 //next 2 line retrieve sheet number 0  and cell (1,1)


 WritableSheet getsht = wkr.getSheet(0);
 WritableCell getcl = getsht.getWritableCell(1, 1);


 //making own font 

WritableFont ft = new WritableFont(WritableFont.ARIAL, 20 , WritableFont.BOLD, true , UnderlineStyle.SINGLE); 
//making Format, which uses font
WritableCellFormat   form   =   new WritableCellFormat( ft);

Number nb = ( Number ) getcl ;          
nb.setCellFormat( form );    


wkr.write();
wkr.close();

Answer 4

我个人使用此代码附加 xls 文件，如果不存在则创建一个。
使用 jxl 2.6：

    public class Excel {

        private String fileName = "excel_file.xls";
        private String sheetName = "sheet1";
        private WritableWorkbook writableWorkbook;
        private int rowCount;
        private Workbook wb;

// assigns checks if file exists or not, both cases we assign it to a WritableWorkbook // object so that we can write to it.
        private void assignWorkBook() throws IOException, BiffException {
    //        File f = new File(System.getProperty("user.dir") +"\\"+fileName);
            File inp = new File(fileName);
            try{
                wb = Workbook.getWorkbook(inp);
                writableWorkbook = Workbook.createWorkbook(inp, wb);
            } catch (FileNotFoundException e){
                writableWorkbook = Workbook.createWorkbook(inp); //Create a new one
            }
        }

        public int getRowCount() {
            return rowCount;
        }

// this function writes a vector to an excel file, checks if there is already a sheet 
// with that name or not, and uses it. then we have to close the Workbook object before 
// we could write to the file, and then we save the file.
// That is, the file is always saved after writing to it.

        public void writeRow(Vector<String> playerVector) throws WriteException, IOException, BiffException {
            assignWorkBook();
            WritableSheet excelSheet;
            if(writableWorkbook.getNumberOfSheets() == 0) {
                excelSheet = writableWorkbook.createSheet(sheetName, 0);
            }
            else {
                excelSheet = writableWorkbook.getSheet(sheetName);
            }
            rowCount = excelSheet.getRows();
            int colCount = 0;
            for(String playerStat:playerVector) {
                Label label = new Label(colCount++, rowCount, playerStat);
                excelSheet.addCell(label);
            }
            if(wb != null) {
                wb.close();
            }
            writableWorkbook.write();
            writableWorkbook.close(); //everytime save it.
        }
    }