咖啡汪日志——做人脸图片上传时，用到的一个very好用的java图片压缩工具类，

package com.cccc.common.utils;

import javax.imageio.ImageIO;
import javax.imageio.stream.FileImageInputStream;
import javax.imageio.stream.FileImageOutputStream;
import java.awt.image.BufferedImage;
import java.io.*;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.ConvolveOp;
import java.awt.image.Kernel;
import java.io.File;
import java.io.IOException;
import javax.swing.ImageIcon;


/**
 * 描述：图片工具类
 *
 * @Author: Yue Zejian
 * @Date: Created in 2021/11/22 15:41
 */
public class ImageUtils {

 public static void main(String[] args) throws Exception{
        //需要压缩的图片地址     123.jpg为需要压缩的图片
        File customaryFile = new File("C://D//Document//123.jpg");
        //压缩过后输出的路径地址    456.jpg 可进行设置为任意名称
        File compressAfter = new File("C://D//Document//456.jpg");

        //长宽需要根据需要等比例调整，会直接影响到压缩后的图片大小，（600*1250 0.8f 可以把17.8M的图片压缩到 68K）
        ImageUtils.imageResize(customaryFile,compressAfter,600,1250,0.8f);
    }

    /**
     * 缩放图片(压缩图片质量，改变图片尺寸)
     * 若原图宽度小于新宽度，则宽度不变
     * @param originalFile 原图片路径地址
     * @param resizedFile 压缩后输出路径地址
     * @param maxWidth 最大宽度
     * @param maxHeight 最大高度
     * @param quality 图片质量参数 0.7f 相当于70%质量
     */
    public static void imageResize(File originalFile, File resizedFile,
                                   int maxWidth,int maxHeight, float quality) throws IOException {

        if (quality > 1) {
            throw new IllegalArgumentException(
                    "图片质量需设置在0.1-1范围");
        }

        ImageIcon ii = new ImageIcon(originalFile.getCanonicalPath());
        Image i = ii.getImage();
        Image resizedImage = null;

        int iWidth = i.getWidth(null);
        int iHeight = i.getHeight(null);

        int newWidth = maxWidth;
        if(iWidth < maxWidth){
            newWidth = iWidth;
        }


        if (iWidth >= iHeight) {
            resizedImage = i.getScaledInstance(newWidth, (newWidth * iHeight)
                    / iWidth, Image.SCALE_SMOOTH);
        }



        int newHeight = maxHeight;
        if(iHeight < maxHeight){
            newHeight = iHeight;
        }

        if(resizedImage==null && iHeight >= iWidth){
            resizedImage = i.getScaledInstance((newHeight * iWidth) / iHeight,
                    newHeight, Image.SCALE_SMOOTH);
        }

        //此代码确保加载图像中的所有像素
        Image temp = new ImageIcon(resizedImage).getImage();

        //创建缓冲图像
        BufferedImage bufferedImage = new BufferedImage(temp.getWidth(null),
                temp.getHeight(null), BufferedImage.TYPE_INT_RGB);

        //将图像复制到缓冲图像
        Graphics g = bufferedImage.createGraphics();

        //清除背景并绘制图像。
        g.setColor(Color.white);
        g.fillRect(0, 0, temp.getWidth(null), temp.getHeight(null));
        g.drawImage(temp, 0, 0, null);
        g.dispose();


        float softenFactor = 0.05f;
        float[] softenArray = { 0, softenFactor, 0, softenFactor,
                1 - (softenFactor * 4), softenFactor, 0, softenFactor, 0 };
        Kernel kernel = new Kernel(3, 3, softenArray);
        ConvolveOp cOp = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null);
        bufferedImage = cOp.filter(bufferedImage, null);

        //将jpeg写入文件

        String formatName = resizedFile.getName().substring(resizedFile.getName().lastIndexOf(".") + 1);

        ImageIO.write(bufferedImage, formatName ,resizedFile );
    }
   
 /**
     * 图片转化为byte数组
     * @param path
     * @return
     */
    public  byte[] image2byte(String path){
        byte[] data = null;
        FileImageInputStream input = null;
        try {
            input = new FileImageInputStream(new File(path));
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];
            int numBytesRead = 0;
            while ((numBytesRead = input.read(buf)) != -1) {
                output.write(buf, 0, numBytesRead);
            }
            data = output.toByteArray();
            output.close();
            input.close();
        } catch (FileNotFoundException ex1) {
            ex1.printStackTrace();
        } catch (IOException ex1) {
            ex1.printStackTrace();
        }
        return data;
    }

    /**
     * byte数组转化为图片
     * @param data
     * @param path
     */
    public  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();
        }
    }
    



}