java 壓縮圖片到指定大小以內實例

package com.first.serv;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;

import javax.imageio.ImageIO;
import javax.imageio.stream.FileImageOutputStream;

public class PicTest {
    public static void main(String[] args) throws IOException {
        long timeStart = System.currentTimeMillis();
        String imgLocalUrl = "E:\\tp\\abc.jpg";
        
        byte[] imgBytes = getByteByPic(imgLocalUrl);
        byte[] resultImg = compressUnderSize(imgBytes,800 * 1024);
        byte2image(resultImg,"E:\\tp\\timga.jpg");
        long timeEnd = System.currentTimeMillis();
        System.out.println("耗時："+ (timeEnd - timeStart));
    }
    
    public static byte[] getByteByPic(String imageUrl) throws IOException{
         File imageFile = new File(imageUrl);
         InputStream inStream = new FileInputStream(imageFile);
         BufferedInputStream bis = new BufferedInputStream(inStream);
         BufferedImage bm = ImageIO.read(bis);
         ByteArrayOutputStream bos = new ByteArrayOutputStream();
         String type = imageUrl.substring(imageUrl.length() - 3);
         ImageIO.write(bm, type, bos);
         bos.flush();
         byte[] data = bos.toByteArray();
         return data;
    }
    /**
     * 將圖片壓縮到指定大小以內
     * 
     * @param srcImgData 源圖片數據
     * @param maxSize 目的圖片大小
     * @return 壓縮后的圖片數據
     */
    public static byte[] compressUnderSize(byte[] srcImgData, long maxSize) {
        double scale = 0.9;
        byte[] imgData = Arrays.copyOf(srcImgData, srcImgData.length);
 
        if (imgData.length > maxSize) {
            do {
                try {
                    imgData = compress(imgData, scale);
 
                } catch (IOException e) {
                    throw new IllegalStateException("壓縮圖片過程中出錯，請及時聯系管理員！", e);
                }
 
            } while (imgData.length > maxSize);
        }
 
        return imgData;
    }
 
    /**
     * 按照 寬高 比例壓縮
     * 
     * @param imgIs 待壓縮圖片輸入流
     * @param scale 壓縮刻度
     * @param out 輸出
     * @return 壓縮后圖片數據
     * @throws IOException 壓縮圖片過程中出錯
     */
    public static byte[] compress(byte[] srcImgData, double scale) throws IOException {
        BufferedImage bi = ImageIO.read(new ByteArrayInputStream(srcImgData));
        int width = (int) (bi.getWidth() * scale); // 源圖寬度
        int height = (int) (bi.getHeight() * scale); // 源圖高度
 
        Image image = bi.getScaledInstance(width, height, Image.SCALE_SMOOTH);
        BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
 
        Graphics g = tag.getGraphics();
        g.setColor(Color.RED);
        g.drawImage(image, 0, 0, null); // 繪制處理后的圖
        g.dispose();
 
        ByteArrayOutputStream bOut = new ByteArrayOutputStream();
        ImageIO.write(tag, "JPEG", bOut);
 
        return bOut.toByteArray();
    }

    //byte數組到圖片
    public static void byte2image(byte[] data,String path){
      if(data.length<3||path.equals("")) return;
      try{
      FileImageOutputStream imageOutput = new FileImageOutputStream(new File(path));
      imageOutput.write(data, 0, data.length);
      imageOutput.close();
      System.out.println("Make Picture success,Please find image in " + path);
      } catch(Exception ex) {
        System.out.println("Exception: " + ex);
        ex.printStackTrace();
      }
    }
    
}