java jxl 向Excel中追加数据而不覆盖原来数据的例子

时间:2021-05-01 17:55:12
向先原来就有数据的Excel写数据是不会覆盖原有的数据,只是在追加数据。
public class Excel {
    public Excel() {
    }
    public void CreateWorkbook(File file, double[] a) {
        try {
            if (!file.exists()) { //判断文件是否已存在,如果没有存在则创建新文件
                jxl.write.WritableWorkbook wwb = Workbook.createWorkbook(new
                        File("result.xls"
                        ));
                jxl.write.WritableSheet ws = wwb.createSheet("Test Sheet 1", 0);
                int i = 0;
                ws.setColumnView(0, 20); //设置列宽
                jxl.write.NumberFormat nf = new jxl.write.NumberFormat(
                        "0.0000000000000000"); //定义数值格式
                WritableCellFormat wcfN = new WritableCellFormat(nf);
                String str2 = "第" + 1 + "次试验";
                Label label = new Label(0, 0, str2);
                ws.addCell(label);
                while (i < a.length) {
                    jxl.write.Number num = new jxl.write.Number(0, i + 1,
                            a[i], wcfN);
                    ws.addCell(num);
                    i++;
                }
                //写入Exel工作表
                wwb.write();
                //关闭Excel工作薄对象
                wwb.close();
            } else {
                Workbook rwb = Workbook.getWorkbook(file);
                File tempfile = new File(System.getProperty("user.dir") +
                                         "\\tempfile.xls");
                WritableWorkbook wwb = Workbook.createWorkbook(tempfile, rwb);
                WritableSheet ws = wwb.getSheet(0);
                int num = rwb.getSheet(0).getColumns();
                int num1 = num + 1;
                ws.setColumnView(num, 20); //设置列宽
                String str2 = "第" + num1 + "次试验"; //添加列名
                Label label = new Label(num, 0, str2);
                ws.addCell(label);
                int i = 0;
                jxl.write.NumberFormat nf = new jxl.write.NumberFormat(
                        "0.000000000000000"); //定义数值格式
                WritableCellFormat wcfN = new WritableCellFormat(nf);
                while (i < a.length) {
                    jxl.write.Number number = new jxl.write.Number(num,
                            i + 1,
                            a[i], wcfN);
                    ws.addCell(number);
                    i++;
                }
                wwb.write();
                wwb.close();
                rwb.close();
                String filename = file.getPath();
                System.out.println("filename:" + filename);
                file.delete();
                tempfile.renameTo(file);
                System.out.println("tempfile:" + tempfile.getPath());
                System.out.println(tempfile.exists());
                System.out.println(file.exists());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}