java修改图片大小

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import javax.imageio.ImageIO;

public class ChangeSize {

public static void main(String[] args) throws Exception {
//读取图片
BufferedInputStream in = new BufferedInputStream(new FileInputStream("E:/test.png"));
//字节流转图片对象
Image bi =ImageIO.read(in);
//获取图像的高度，宽度
int height=bi.getHeight(null);
int width =bi.getWidth(null);
//构建图片流
BufferedImage tag = new BufferedImage(width / 2, height / 2, BufferedImage.TYPE_INT_RGB);
//绘制改变尺寸后的图
tag.getGraphics().drawImage(bi, 0, 0,width / 2, height / 2, null);
//输出流
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("E:/copy.png"));
//JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
//encoder.encode(tag);
ImageIO.write(tag, "PNG",out);
in.close();
out.close();
//转字节流
//ByteArrayOutputStream out = new ByteArrayOutputStream();

//ImageIO.write(tag, "PNG",out);

}
}