java修改图片大小

 1 import java.awt.Image;
 2 import java.awt.image.BufferedImage;
 3 import java.io.BufferedInputStream;
 4 import java.io.BufferedOutputStream;
 5 import java.io.FileInputStream;
 6 import java.io.FileOutputStream;
 7 
 8 import javax.imageio.ImageIO;
 9 
10 
11 
12 public class ChangeSize {
13     
14     
15     public static void main(String[] args) throws Exception {
16         //读取图片
17         BufferedInputStream in = new BufferedInputStream(new FileInputStream("E:/test.png"));
18         //字节流转图片对象
19         Image bi =ImageIO.read(in);
20         //获取图像的高度，宽度
21         int height=bi.getHeight(null);
22         int width =bi.getWidth(null);
23         //构建图片流
24         BufferedImage tag = new BufferedImage(width / 2, height / 2, BufferedImage.TYPE_INT_RGB);
25         //绘制改变尺寸后的图
26         tag.getGraphics().drawImage(bi, 0, 0,width / 2, height / 2, null);  
27         //输出流
28         BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream("E:/copy.png"));
29         //JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
30         //encoder.encode(tag);
31         ImageIO.write(tag, "PNG",out);
32         in.close();
33         out.close();
//转字节流
//ByteArrayOutputStream out = new ByteArrayOutputStream();

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

//InputStream is = new ByteArrayInputStream(out.toByteArray());

34         }
35 }