java编程简单获取图片像素的方法

package cn.net.comsys.sso;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.*;
public class Test {
public static void main(String args[]) {
File file = new File("a.bmp");
BufferedImage bi = null;
try {
bi = ImageIO.read(file);
} catch (Exception e) {
e.printStackTrace();
}
int width = bi.getWidth(); // 像素
int height = bi.getHeight(); // 像素
System.out.println("width=" + width + ",height=" + height + ".");
}
}