使用Apache.POI读写Excel的Java内存问题

我正在尝试读取Excel文件...进行一些更改...保存到新文件。

我已经创建了带有按钮的小表格。

• 它将加载Excel文件并将所有数据加载到我创建的类的Array列表中。
• 它将遍历数组列表并更改对象中的几个属性。
• 它将数据保存到新的Excel文件中。
• 最后，它将清除“阵列”列表并显示完成消息框。

现在的问题是内存问题。
加载表单后，我可以在Windows任务管理器中看到... javaw正在使用约23MB。
在读写excel期间...内存拍摄高达170MB。
清除阵列列表后...。内存没有清除，并保持在150MB左右。

下面的代码附加到事件单击按钮。

MouseListener mouseListener = new MouseAdapter() {
        public void mouseReleased(MouseEvent mouseEvent) {
            if (SwingUtilities.isLeftMouseButton(mouseEvent)) {
                ArrayList<Address> addresses = ExcelFunctions.getExcelData(fn);
                for (Address address : addresses){
                    address.setZestimate(Integer.toString(rnd.nextInt(45000)));
                    address.setRedfinestimate(Integer.toString(rnd.nextInt(45000)));
                }
                ExcelFunctions.saveToExcel(ofn,addresses);
                addresses.clear();
                JOptionPane.showMessageDialog(null, "Done");
            }
        }
    };

该类中Reading / Excel文件的代码。

public class ExcelFunctions {
public static ArrayList<Address> getExcelData(String fn)
{
    ArrayList<Address> output = new ArrayList<Address>();
    try
    {
        FileInputStream file = new FileInputStream(new File(fn));

        //Create Workbook instance holding reference to .xlsx file
        XSSFWorkbook workbook = new XSSFWorkbook(file);

        //Get first/desired sheet from the workbook
        XSSFSheet sheet = workbook.getSheetAt(0);
        System.out.println(sheet.getSheetName());
        //Iterate through each rows one by one
        Iterator<Row> rowIterator = sheet.iterator();
        while (rowIterator.hasNext())
        {
            Row row = rowIterator.next();
            int r = row.getRowNum();
            int fc= row.getFirstCellNum();
            int lc = row.getLastCellNum();
            String msg = "Row:"+ r +"FColumn:"+ fc + "LColumn"+lc;
            System.out.println(msg);
            if (row.getRowNum() > 0) {
                Address add = new Address();
                Cell c0 = row.getCell(0);
                Cell c1 = row.getCell(1);
                Cell c2 = row.getCell(2);
                Cell c3 = row.getCell(3);
                Cell c4 = row.getCell(4);
                Cell c5 = row.getCell(5);
                if (c0 != null){c0.setCellType(Cell.CELL_TYPE_STRING);add.setState(c0.toString());}
                if (c1 != null){c1.setCellType(Cell.CELL_TYPE_STRING);add.setCity(c1.toString());}
                if (c2 != null){c2.setCellType(Cell.CELL_TYPE_STRING);add.setZipcode(c2.toString());}
                if (c3 != null){c3.setCellType(Cell.CELL_TYPE_STRING);add.setAddress(c3.getStringCellValue());}
                if (c4 != null){c4.setCellType(Cell.CELL_TYPE_STRING);add.setZestimate(c4.getStringCellValue());}
                if (c5 != null){c5.setCellType(Cell.CELL_TYPE_STRING);add.setRedfinestimate(c5.getStringCellValue());}
                output.add(add);
                c0=null;c1=null;c2=null;c3=null;c4=null;c5=null;
            }
        }
        workbook.close();
        file.close();
    }
    catch (Exception e)
    {
        System.out.println(e.getMessage());
    }
    return output;
}

public static void saveToExcel(String ofn, ArrayList<Address> addresses) {
    XSSFWorkbook workbook = new XSSFWorkbook();
    XSSFSheet sheet = workbook.createSheet("Addresses");

    Row header = sheet.createRow(0);
    header.createCell(0).setCellValue("State");
    header.createCell(1).setCellValue("City");
    header.createCell(2).setCellValue("Zip");
    header.createCell(3).setCellValue("Address");
    header.createCell(4).setCellValue("Zestimates");
    header.createCell(5).setCellValue("Redfin Estimate");

    int row = 1;

    for (Address address : addresses){
        Row dataRow = sheet.createRow(row);
        dataRow.createCell(0).setCellValue(address.getState());
        dataRow.createCell(1).setCellValue(address.getCity());
        dataRow.createCell(2).setCellValue(address.getZipcode());
        dataRow.createCell(3).setCellValue(address.getAddress());
        dataRow.createCell(4).setCellValue(address.getZestimate());
        dataRow.createCell(5).setCellValue(address.getRedfinestimate());
        row++;
    }


    try {
        FileOutputStream out =  new FileOutputStream(new File(ofn));
        workbook.write(out);
        out.close();
        workbook.close();
        System.out.println("Excel with foumula cells written successfully");

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}}

我无法弄清楚问题出在哪里。我也关闭工作簿/输入流/输出流并清除Arraylist。