Java实现图片压缩【转载】

今天无意中发现这篇文章，可以帮助实现图片压缩，以后有限定图片大小的就可以自己实现了。

package com.bonc.ioc.lmp.common.util;import java.awt.Graphics2D;import java.awt.Rectangle;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 java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import javax.imageio.ImageIO;import org.junit.Test;  /**   * 图片工具类，完成图片的截取 * 所有方法返回值均未boolean型   */  public class ImageHelper {  /**       * 实现图像的等比缩放       * @param source       * @param targetW       * @param targetH       * @return       */      private 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_INTERPOLATION,                   RenderingHints.VALUE_INTERPOLATION_BICUBIC);           g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));           g.dispose();           return target;       }        /**       * 实现图像的等比缩放和缩放后的截取, 处理成功返回true, 否则返回false       * @param inFilePath 要截取文件的路径       * @param outFilePath 截取后输出的路径       * @param width 要截取宽度       * @param hight 要截取的高度       * @throws Exception       */      public static boolean compress(String inFilePath, String outFilePath,               int width, int hight) {        boolean ret = false;        File file = new File(inFilePath);        File saveFile = new File(outFilePath);        InputStream in = null;        try {            in = new FileInputStream(file);            ret = compress(in, saveFile, width, hight);        } catch (FileNotFoundException e) {            e.printStackTrace();            ret = false;        } finally{            if(null != in){                try {                    in.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }         return ret;    }      /**       * 实现图像的等比缩放和缩放后的截取, 处理成功返回true, 否则返回false       * @param in 要截取文件流     * @param outFilePath 截取后输出的路径       * @param width 要截取宽度       * @param hight 要截取的高度       * @throws Exception       */      public static boolean compress(InputStream in, File saveFile,               int width, int hight) {//     boolean ret = false;        BufferedImage srcImage = null;        try {            srcImage = ImageIO.read(in);        } catch (IOException e) {            e.printStackTrace();            return false;        }         if (width > 0 || hight > 0) {            // 原图的大小            int sw = srcImage.getWidth();            int sh = srcImage.getHeight();            // 如果原图像的大小小于要缩放的图像大小，直接将要缩放的图像复制过去            if (sw > width && sh > hight) {                srcImage = resize(srcImage, width, hight);            } else {                String fileName = saveFile.getName();                String formatName = fileName.substring(fileName                        .lastIndexOf('.') + 1);                try {                    ImageIO.write(srcImage, formatName, saveFile);                } catch (IOException e) {                    e.printStackTrace();                    return false;                }                return true;            }        }        // 缩放后的图像的宽和高        int w = srcImage.getWidth();        int h = srcImage.getHeight();        // 如果缩放后的图像和要求的图像宽度一样，就对缩放的图像的高度进行截取        if (w == width) {            // 计算X轴坐标            int x = 0;            int y = h / 2 - hight / 2;            try {                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);            } catch (IOException e) {                e.printStackTrace();                return false;            }        }        // 否则如果是缩放后的图像的高度和要求的图像高度一样，就对缩放后的图像的宽度进行截取        else if (h == hight) {            // 计算X轴坐标            int x = w / 2 - width / 2;            int y = 0;            try {                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);            } catch (IOException e) {                e.printStackTrace();                return false;                            }        }         return true;    }     /**     * 实现图像的等比缩放和缩放后的截取, 处理成功返回true, 否则返回false     * @param in 图片输入流     * @param saveFile 压缩后的图片输出流     * @param proportion 压缩比     * @throws Exception     */    public static boolean compress(InputStream in, File saveFile, int proportion) {        if(null == in                ||null == saveFile                ||proportion < 1){// 检查参数有效性            //LoggerUtil.error(ImageHelper.class, "--invalid parameter, do nothing!");            return false;        }         BufferedImage srcImage = null;        try {            srcImage = ImageIO.read(in);        } catch (IOException e) {            e.printStackTrace();            return false;        }        // 原图的大小        int width = srcImage.getWidth() / proportion;        int hight = srcImage.getHeight() / proportion;         srcImage = resize(srcImage, width, hight);         // 缩放后的图像的宽和高        int w = srcImage.getWidth();        int h = srcImage.getHeight();        // 如果缩放后的图像和要求的图像宽度一样，就对缩放的图像的高度进行截取        if (w == width) {            // 计算X轴坐标            int x = 0;            int y = h / 2 - hight / 2;            try {                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);            } catch (IOException e) {                e.printStackTrace();                return false;            }        }        // 否则如果是缩放后的图像的高度和要求的图像高度一样，就对缩放后的图像的宽度进行截取        else if (h == hight) {            // 计算X轴坐标            int x = w / 2 - width / 2;            int y = 0;            try {                saveSubImage(srcImage, new Rectangle(x, y, width, hight), saveFile);            } catch (IOException e) {                e.printStackTrace();                return false;            }        }         return true;    }     /**     * 实现缩放后的截图     * @param image 缩放后的图像     * @param subImageBounds 要截取的子图的范围     * @param subImageFile 要保存的文件     * @throws IOException      */      private static void saveSubImage(BufferedImage image,               Rectangle subImageBounds, File subImageFile) throws IOException {           if (subImageBounds.x < 0 || subImageBounds.y < 0                  || subImageBounds.width - subImageBounds.x > image.getWidth()                   || subImageBounds.height - subImageBounds.y > image.getHeight()) {               //LoggerUtil.error(ImageHelper.class, "Bad subimage bounds");               return;           }           BufferedImage subImage = image.getSubimage(subImageBounds.x,subImageBounds.y, subImageBounds.width, subImageBounds.height);           String fileName = subImageFile.getName();           String formatName = fileName.substring(fileName.lastIndexOf('.') + 1);           ImageIO.write(subImage, formatName, subImageFile);    }              @Test   public static void main(String[] args) throws Exception {        /**        * saveSubImage 截图类的使用        * srcImage 为BufferedImage对象        * Rectangle    为需要截图的长方形坐标        * saveFile 需要保存的路径及名称        * **/        //需要截图的长方形坐标        /*Rectangle rect =new Rectangle();        rect.x=40;        rect.y=40;        rect.height=160;        rect.width=160;         InputStream in = null;        //需要保存的路径及名称        File saveFile = new File("d:\\ioc\\files\\aaa2.jpg");        //需要进行处理的图片的路径        in = new FileInputStream(new File("d:\\ioc\\files\\aaa.jpg"));        BufferedImage srcImage = null;        //将输入的数据转为BufferedImage对象        srcImage = ImageIO.read(in);         ImageHelper img=new ImageHelper();        img.saveSubImage(srcImage, rect, saveFile);*/        /**        * compress 图片缩放类的使用(缩略图)        * srcImage 为InputStream对象        * Rectangle    为需要截图的长方形坐标        * proportion 为压缩比例        * **/        InputStream in = null;        //缩放后需要保存的路径        File saveFile = new File("d:\\ioc\\files\\aaa2.jpg");        try {            //原图片的路径            in = new FileInputStream(new File("d:\\ioc\\files\\aaa.jpg"));            if(compress(in, saveFile, 10)){            System.out.println("图片压缩十倍！");            }        } catch (Exception e) {            e.printStackTrace();        } finally {            in.close();        }    }}

文章来源：http://blog.csdn.net/javafay/article/details/8031620【点滴而为知】