java实现图片裁剪缩放工具类

import java.awt.Image;    import java.awt.Rectangle;    import java.awt.geom.AffineTransform;    import java.awt.image.AffineTransformOp;    import java.awt.image.BufferedImage;    import java.io.File;    import java.io.FileInputStream;    import java.io.IOException;    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 ImageHelper {        /*        * 根据尺寸图片居中裁剪        */         public static void cutCenterImage(String src,String dest,int w,int h) throws IOException{              Iterator iterator = ImageIO.getImageReadersByFormatName("jpg");              ImageReader reader = (ImageReader)iterator.next();              InputStream in=new FileInputStream(src);             ImageInputStream iis = ImageIO.createImageInputStream(in);              reader.setInput(iis, true);              ImageReadParam param = reader.getDefaultReadParam();              int imageIndex = 0;              Rectangle rect = new Rectangle((reader.getWidth(imageIndex)-w)/2, (reader.getHeight(imageIndex)-h)/2, w, h);               param.setSourceRegion(rect);              BufferedImage bi = reader.read(0,param);                ImageIO.write(bi, "jpg", new File(dest));                          }        /*        * 图片裁剪二分之一        */         public static void cutHalfImage(String src,String dest) throws IOException{              Iterator iterator = ImageIO.getImageReadersByFormatName("jpg");              ImageReader reader = (ImageReader)iterator.next();              InputStream in=new FileInputStream(src);             ImageInputStream iis = ImageIO.createImageInputStream(in);              reader.setInput(iis, true);              ImageReadParam param = reader.getDefaultReadParam();              int imageIndex = 0;              int width = reader.getWidth(imageIndex)/2;              int height = reader.getHeight(imageIndex)/2;              Rectangle rect = new Rectangle(width/2, height/2, width, height);              param.setSourceRegion(rect);              BufferedImage bi = reader.read(0,param);                ImageIO.write(bi, "jpg", new File(dest));            }        /*        * 图片裁剪通用接口        */            public static void cutImage(String src,String dest,int x,int y,int w,int h) throws IOException{                Iterator iterator = ImageIO.getImageReadersByFormatName("jpg");                ImageReader reader = (ImageReader)iterator.next();                InputStream in=new FileInputStream(src);               ImageInputStream iis = ImageIO.createImageInputStream(in);                reader.setInput(iis, true);                ImageReadParam param = reader.getDefaultReadParam();                Rectangle rect = new Rectangle(x, y, w,h);                 param.setSourceRegion(rect);                BufferedImage bi = reader.read(0,param);                  ImageIO.write(bi, "jpg", new File(dest));                       }         /*        * 图片缩放        */        public static void zoomImage(String src,String dest,int w,int h) throws Exception {            double wr=0,hr=0;            File srcFile = new File(src);            File destFile = new File(dest);            BufferedImage bufImg = ImageIO.read(srcFile);            Image Itemp = bufImg.getScaledInstance(w, h, bufImg.SCALE_SMOOTH);            wr=w*1.0/bufImg.getWidth();            hr=h*1.0 / bufImg.getHeight();            AffineTransformOp ato = new AffineTransformOp(AffineTransform.getScaleInstance(wr, hr), null);            Itemp = ato.filter(bufImg, null);            try {                ImageIO.write((BufferedImage) Itemp,dest.substring(dest.lastIndexOf(".")+1), destFile);            } catch (Exception ex) {                ex.printStackTrace();            }                    }    }