根据尺寸裁剪照片 java

import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;
import java.io.File;

import javax.imageio.ImageIO;

public class ImageThumb {
public static BufferedImage resize(BufferedImage source, int targetW,
int targetH) {
// targetW，targetH分别表示目标长和宽
int type = source.getType();
BufferedImage target = null;
double sx = (double) targetW / source.getWidth();
double sy = (double) targetH / source.getHeight();
// 这里想实现在targetW，targetH范围内实现等比缩放。如果不需要等比缩放
// 则将下面的if else语句注释即可
if (sx > sy) {
sx = sy;
targetW = (int) (sx * source.getWidth());
} else {
sy = sx;
targetH = (int) (sy * source.getHeight());
}
if (type == BufferedImage.TYPE_CUSTOM) { // handmade
ColorModel cm = source.getColorModel();
WritableRaster raster = cm.createCompatibleWritableRaster(targetW,
targetH);
boolean alphaPremultiplied = cm.isAlphaPremultiplied();
target = new BufferedImage(cm, raster, alphaPremultiplied, null);
} else
target = new BufferedImage(targetW, targetH, type);
Graphics2D g = target.createGraphics();
// smoother than exlax:
g.setRenderingHint(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));
g.dispose();
return target;
}

public static void saveImageAsJpg(String fromFileStr, String saveToFileStr,
int width, int hight) throws Exception {
BufferedImage srcImage;
// String ex =
// fromFileStr.substring(fromFileStr.indexOf("."),fromFileStr.length());
String imgType = "JPEG";
if (fromFileStr.toLowerCase().endsWith(".png")) {
imgType = "PNG";
}
// System.out.println(ex);
File saveFile = new File(saveToFileStr);
File fromFile = new File(fromFileStr);
srcImage = ImageIO.read(fromFile);
if (width > 0 || hight > 0) {
srcImage = resize(srcImage, width, hight);
}
ImageIO.write(srcImage, imgType, saveFile);

}



/**示例*/
public static void main(String argv[]) {
try {
// 参数1(from),参数2(to),参数3(宽),参数4(高)
ImageThumb.saveImageAsJpg("D:\\images\\op.jpg", "D:\\images\\op(mini).jpg",
200, 200);
} catch (Exception e) {
e.printStackTrace();
}

}
}