Java Graphics - 如何使用ImageIO.write()方法创建PNG类型图像

import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;

public class Main {
  public static void main(String[] args) throws Exception {
    BufferedImage bi = new BufferedImage(100, 100, BufferedImage.TYPE_INT_ARGB);
    ImageIO.write(bi, "png", new File("test.png"));
  }
}