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Java實現圖片壓縮【轉載】

今天無意中發現這篇文章,可以幫助實現圖片壓縮,以後有限定圖片大小的就可以自己實現了。

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;
 
 

/**  
 * 圖片工具類,完成圖片的擷取
 * 所有方法返回值均未boolean型  
 */  
public class ImageHelper {
	  /**  
     * 實現影象的等比縮放  
     * @param source  
     * @param targetW  
     * @param targetH  
     * @return  
     */  
    private static BufferedImage resize(BufferedImage source, int targetW,   
            int targetH) {   
        // targetW,targetH分別表示目標長和寬   
        int type = source.getType();   
        BufferedImage target = null;   
        double sx = (double) targetW / source.getWidth();   
        double sy = (double) targetH / source.getHeight();   
        // 這裡想實現在targetW,targetH範圍內實現等比縮放。如果不需要等比縮放   
        // 則將下面的if else語句註釋即可   
        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;   
    }   
 
    /**  
     * 實現影象的等比縮放和縮放後的擷取, 處理成功返回true, 否則返回false  
     * @param inFilePath 要擷取檔案的路徑  
     * @param outFilePath 擷取後輸出的路徑  
     * @param width 要擷取寬度  
     * @param hight 要擷取的高度  
     * @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;
    } 
 
    /**  
     * 實現影象的等比縮放和縮放後的擷取, 處理成功返回true, 否則返回false  
     * @param in 要擷取檔案流
     * @param outFilePath 擷取後輸出的路徑  
     * @param width 要擷取寬度  
     * @param hight 要擷取的高度  
     * @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) {
            // 原圖的大小
            int sw = srcImage.getWidth();
            int sh = srcImage.getHeight();
            // 如果原影象的大小小於要縮放的影象大小,直接將要縮放的影象複製過去
            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;
            }
        }
        // 縮放後的影象的寬和高
        int w = srcImage.getWidth();
        int h = srcImage.getHeight();
        // 如果縮放後的影象和要求的影象寬度一樣,就對縮放的影象的高度進行擷取
        if (w == width) {
            // 計算X軸座標
            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;
            }
        }
        // 否則如果是縮放後的影象的高度和要求的影象高度一樣,就對縮放後的影象的寬度進行擷取
        else if (h == hight) {
            // 計算X軸座標
            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;
    }
 
    /**
     * 實現影象的等比縮放和縮放後的擷取, 處理成功返回true, 否則返回false
     * @param in 圖片輸入流
     * @param saveFile 壓縮後的圖片輸出流
     * @param proportion 壓縮比
     * @throws Exception
     */
    public static boolean compress(InputStream in, File saveFile, int proportion) {
        if(null == in
                ||null == saveFile
                ||proportion < 1){// 檢查引數有效性
            //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;
        }
        // 原圖的大小
        int width = srcImage.getWidth() / proportion;
        int hight = srcImage.getHeight() / proportion;
 
        srcImage = resize(srcImage, width, hight);
 
        // 縮放後的影象的寬和高
        int w = srcImage.getWidth();
        int h = srcImage.getHeight();
        // 如果縮放後的影象和要求的影象寬度一樣,就對縮放的影象的高度進行擷取
        if (w == width) {
            // 計算X軸座標
            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;
            }
        }
        // 否則如果是縮放後的影象的高度和要求的影象高度一樣,就對縮放後的影象的寬度進行擷取
        else if (h == hight) {
            // 計算X軸座標
            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;
    }
 
    /**
     * 實現縮放後的截圖
     * @param image 縮放後的影象
     * @param subImageBounds 要擷取的子圖的範圍
     * @param subImageFile 要儲存的檔案
     * @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 截圖類的使用
        * srcImage 為BufferedImage物件
        * Rectangle    為需要截圖的長方形座標
        * saveFile 需要儲存的路徑及名稱
        * **/
        //需要截圖的長方形座標
        /*Rectangle rect =new Rectangle();
        rect.x=40;
        rect.y=40;
        rect.height=160;
        rect.width=160;
 
        InputStream in = null;
        //需要儲存的路徑及名稱
        File saveFile = new File("d:\\ioc\\files\\aaa2.jpg");
        //需要進行處理的圖片的路徑
        in = new FileInputStream(new File("d:\\ioc\\files\\aaa.jpg"));
        BufferedImage srcImage = null;
        //將輸入的資料轉為BufferedImage物件
        srcImage = ImageIO.read(in);
 
        ImageHelper img=new ImageHelper();
        img.saveSubImage(srcImage, rect, saveFile);*/
 
       /**
        * compress 圖片縮放類的使用(縮圖)
        * srcImage 為InputStream物件
        * Rectangle    為需要截圖的長方形座標
        * proportion 為壓縮比例
        * **/
        InputStream in = null;
        //縮放後需要儲存的路徑
        File saveFile = new File("d:\\ioc\\files\\aaa2.jpg");
        try {
            //原圖片的路徑
            in = new FileInputStream(new File("d:\\ioc\\files\\aaa.jpg"));
            if(compress(in, saveFile, 10)){
            	System.out.println("圖片壓縮十倍!");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            in.close();
        }
    }
}
文章來源:http://blog.csdn.net/javafay/article/details/8031620【點滴而為知】