用java如何在内存中存储文件？

import java.io.*;

public class FileStorageExample {
    public static void main(String[] args) {
        String filePath = "path/to/file.txt";
        
        // 使用字节数组存储文件
        try {
            File file = new File(filePath);
            FileInputStream fis = new FileInputStream(file);
            byte[] data = new byte[(int) file.length()];
            fis.read(data);
            fis.close();
            
            // 在内存中操作文件数据
            // ...
            
            FileOutputStream fos = new FileOutputStream(file);
            fos.write(data);
            fos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        // 使用字节缓冲流存储文件
        try {
            File file = new File(filePath);
            FileInputStream fis = new FileInputStream(file);
            BufferedInputStream bis = new BufferedInputStream(fis);
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = bis.read(buffer)) != -1) {
                baos.write(buffer, 0, bytesRead);
            }
            
            bis.close();
            
            // 在内存中操作文件数据
            // ...
            
            FileOutputStream fos = new FileOutputStream(file);
            BufferedOutputStream bos = new BufferedOutputStream(fos);
            bos.write(baos.toByteArray());
            bos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}