可以通過以下方法將InputStream轉換為File：

import java.io.*;

public class Main {
    public static void main(String[] args) {
        InputStream inputStream = null;
        FileOutputStream fileOutputStream = null;
        try {
            inputStream = new FileInputStream("input.txt");
            File file = new File("output.txt");
            fileOutputStream = new FileOutputStream(file);

            byte[] buffer = new byte[1024];
            int length;
            while ((length = inputStream.read(buffer)) != -1) {
                fileOutputStream.write(buffer, 0, length);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (inputStream != null) {
                    inputStream.close();
                }
                if (fileOutputStream != null) {
                    fileOutputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

此代碼段首先創建一個InputStream對象來讀取文件內容，然后創建一個File對象來寫入內容。通過讀取InputStream流的內容，并將其寫入到File中，實現了InputStream轉換為File的功能。