java - HSSFWorkbook 对象不保留通过不同方法添加到其中的工作表

Question

`   class A {
    private HSSFWorkbook workbook;

    public A() {
        workbook = new HSSFWorkbook();
    }

    public void method1() {
        workbook.createSheet("Sheet1");
        System.out.println(" No of sheets: " + workbook.getNumberOfSheets());
        method2();
    }

    public void method2() {
        System.out.println(" No of sheets: " + workbook.getNumberOfSheets());
    }
}

在上面的代码中，我在构造函数中创建工作簿对象...并在方法1中创建“Sheet1”及其打印工作表数量:1在方法1中但在方法2中工作表数量:0...为什么同一个工作簿对象在不同的​​方法中表现不同。请有人帮助我...

Answer 1

我前段时间还创建了一个 Class MyWorkbook ，我可以在其中添加新的 Sheet ，我缩短了以下代码以仅显示添加首先和所有其他 Sheet

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

public class MyWorkbook {

    private final HSSFWorkbook workbook;

    public MyWorkbook() {
        this.workbook = new HSSFWorkbook();
    }

    public void createNewSheet() {
        workbook.createSheet("Sheet1");
        printNumberOfSheets(workbook);
        // here i add the second sheet
        createAnotherSheet();
    }

    public void createAnotherSheet() {
        workbook.createSheet();
        printNumberOfSheets(workbook);
    }

    private void printNumberOfSheets(final HSSFWorkbook workbook) {
        System.out.println("This workbook contains of " + (workbook.getNumberOfSheets() > 1 ? + workbook.getNumberOfSheets() + " Sheets" : workbook.getNumberOfSheets() + " Sheet"));
    } 

    public HSSFWorkbook getWorkbook() {
        return workbook;
    }


    public static void main(String[] args) {
        MyWorkbook mw = new MyWorkbook();
        mw.createNewSheet();

        // workbook contains only 1 sheet
        mw.printNumberOfSheets(mw.getWorkbook());

        // here i add the 3rd sheet
        mw.createAnotherSheet();

        // now our workbook contains of 3 sheets
        mw.printNumberOfSheets(mw.getWorkbook());
    }
}

帕特里克