JAVA实现根据图片生成缩略图、裁剪、压缩图片

依赖（用来复制文件，可以根据自己的来）

   <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.8.0</version>
        </dependency>

ImageScaleUtils.java

import org.apache.commons.io.FileUtils;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

/**
 * @author
 * @date 2021/10/11
 */
public class ImageScaleUtils {

    /**
     * 缩小图片
     *
     * @param srcFile 原图片
     * @param destFile 目标图片
     * @param boxWidth  缩略图最大宽度
     * @param boxHeight 缩略图最大高度
     * @throws IOException
     */
    public static void resizeFix(File srcFile, File destFile, int boxWidth,
                                 int boxHeight) throws IOException {
        BufferedImage srcImgBuff = ImageIO.read(srcFile);
        int width = srcImgBuff.getWidth();
        int height = srcImgBuff.getHeight();
        if (width <= boxWidth && height <= boxHeight) {
            FileUtils.copyFile(srcFile, destFile);
            return;
        }
        int zoomWidth;
        int zoomHeight;
        if ((float) width / height > (float) boxWidth / boxHeight) {
            zoomWidth = boxWidth;
            zoomHeight = Math.round((float) boxWidth * height / width);
        } else {
            zoomWidth = Math.round((float) boxHeight * width / height);
            zoomHeight = boxHeight;
        }
        BufferedImage imgBuff = scaleImage(srcImgBuff, width, height,
                zoomWidth, zoomHeight);
        writeFile(imgBuff, destFile);
    }

    /**
     * 裁剪并压缩
     *
     * @param srcFile 原文件
     * @param destFile 目标文件
     * @param boxWidth 缩略图最大宽度
     * @param boxHeight 缩略图最大高度
     * @param cutTop 裁剪TOP
     * @param cutLeft 裁剪LEFT
     * @param cutWidth  裁剪宽度
     * @param catHeight  裁剪高度
     * @throws IOException
     */
    public static void resizeFix(File srcFile, File destFile, int boxWidth,
                                 int boxHeight, int cutTop, int cutLeft, int cutWidth, int catHeight)
            throws IOException {
        BufferedImage srcImgBuff = ImageIO.read(srcFile);
        srcImgBuff = srcImgBuff.getSubimage(cutTop, cutLeft, cutWidth,
                catHeight);
        int width = srcImgBuff.getWidth();
        int height = srcImgBuff.getHeight();
        if (width <= boxWidth && height <= boxHeight) {
            writeFile(srcImgBuff, destFile);
            return;
        }
        int zoomWidth;
        int zoomHeight;
        if ((float) width / height > (float) boxWidth / boxHeight) {
            zoomWidth = boxWidth;
            zoomHeight = Math.round((float) boxWidth * height / width);
        } else {
            zoomWidth = Math.round((float) boxHeight * width / height);
            zoomHeight = boxHeight;
        }
        BufferedImage imgBuff = scaleImage(srcImgBuff, width, height,
                zoomWidth, zoomHeight);
        writeFile(imgBuff, destFile);
    }

    public static void writeFile(BufferedImage imgBuf, File destFile)
            throws IOException {
        File parent = destFile.getParentFile();
        if (!parent.exists()) {
            parent.mkdirs();
        }
        ImageIO.write(imgBuf, "jpeg", destFile);
    }

    private static BufferedImage scaleImage(BufferedImage srcImgBuff,
                                            int width, int height, int zoomWidth, int zoomHeight) {
        int[] colorArray = srcImgBuff.getRGB(0, 0, width, height, null, 0,
                width);
        BufferedImage outBuff = new BufferedImage(zoomWidth, zoomHeight,
                BufferedImage.TYPE_INT_RGB);
        // 宽缩小的倍数
        float wScale = (float) width / zoomWidth;
        int wScaleInt = (int) (wScale + 0.5);
        // 高缩小的倍数
        float hScale = (float) height / zoomHeight;
        int hScaleInt = (int) (hScale + 0.5);
        int area = wScaleInt * hScaleInt;
        int x0, x1, y0, y1;
        int color;
        long red, green, blue;
        int x, y, i, j;
        for (y = 0; y < zoomHeight; y++) {
            // 得到原图高的Y坐标
            y0 = (int) (y * hScale);
            y1 = y0 + hScaleInt;
            for (x = 0; x < zoomWidth; x++) {
                x0 = (int) (x * wScale);
                x1 = x0 + wScaleInt;
                red = green = blue = 0;
                for (i = x0; i < x1; i++) {
                    for (j = y0; j < y1; j++) {
                        color = colorArray[width * j + i];
                        red += getRedValue(color);
                        green += getGreenValue(color);
                        blue += getBlueValue(color);
                    }
                }
                outBuff.setRGB(x, y, comRGB((int) (red / area),
                        (int) (green / area), (int) (blue / area)));
            }
        }
        return outBuff;
    }

    private static int getRedValue(int rgbValue) {
        return (rgbValue & 0x00ff0000) >> 16;
    }

    private static int getGreenValue(int rgbValue) {
        return (rgbValue & 0x0000ff00) >> 8;
    }

    private static int getBlueValue(int rgbValue) {
        return rgbValue & 0x000000ff;
    }

    private static int comRGB(int redValue, int greenValue, int blueValue) {
        return (redValue << 16) + (greenValue << 8) + blueValue;
    }

    public static void main(String[] args) throws Exception{
        resizeFix(
                new File("C:\\Users\\Public\\Pictures\\Sample Pictures\\Chrysanthemum.jpg"), new File(
                        "C:\\Users\\Public\\Pictures\\Sample Pictures\\Chrysanthemum-1.jpg"), 310, 310);

        resizeFix(
                new File("C:\\Users\\Public\\Pictures\\Sample Pictures\\Chrysanthemum.jpg"), new File(
                        "C:\\Users\\Public\\Pictures\\Sample Pictures\\Chrysanthemum-2.jpg"), 310, 310,140,200,300,400);
    }
}