java截取图片部分尺寸

package util;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.Iterator;
import javax.imageio.ImageIO;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;

public class ImgCut {
 
 public void readUsingImageReader(String src, String dest, int w, int h)
   throws Exception {
  // 取得图片读入器
  Iterator readers = ImageIO.getImageReadersByFormatName("jpg");
  ImageReader reader = (ImageReader) readers.next();
  // 取得图片读入流
  InputStream source = new FileInputStream(src);
  ImageInputStream iis = ImageIO.createImageInputStream(source);
  reader.setInput(iis, true);
  // 图片参数
  ImageReadParam param = reader.getDefaultReadParam();
  // 100，200是左上起始位置，300就是取宽度为300的，就是从100开始取300宽，就是横向100~400，同理纵向200~350的区域就取高度150
  // Rectangle rect = new Rectangle(100, 200, 300, 150);//
  int hh = 0;
  if (h > 100)
  hh = (h - 100) / 3;
  Rectangle rect = new Rectangle(0, hh, 227, 100);
  param.setSourceRegion(rect);
  BufferedImage bi = reader.read(0, param);
  ImageIO.write(bi, "jpg", new File(dest));
 }
 public static void main(String[] args) throws Exception { // main方法测试用
  ImgCut t = new ImgCut();
  t.readUsingImageReader("d://2.jpg", "d://3.jpg", 227, 163);
 }
}