Thumbnailator圖片處理，壓縮、旋轉、水印、剪切等

第一步：修改pom.xml文件，添加依賴

<dependency>
    <groupId>net.coobird</groupId>
    <artifactId>thumbnailator</artifactId>
    <version>0.4.11</version>
</dependency>

第二步：工具類展示（廢話不多，直接乾貨）
此工具類只做簡單示範，具體使用請結合業務實現

public class ImgYsUtil {

    //測試原圖
    private static File fromPic = new File("F:\\869074038846502_20200610140742_0A_0_0_res.jpg");

    //水印
    private static File waterPic = new File("F:\\20150327232807070.jpg");

    /**
     * 壓縮圖片
     * @throws Exception
     */
    public static void reduceImage() throws Exception{
        File toPic = new File("F:\\20150327232556186_test.jpg");
        Thumbnails.of(fromPic).scale(1f).outputQuality(0.25f).toFile(toPic);
    }

    /**
     * 修改圖片大小:遵循原圖高寬比例
     * @throws Exception
     */
    public static void modifyImageSize(int width,int height) throws Exception{
        File toPic = new File("F:\\20150327232556186_"+ width + "x" +height + ".jpg");
        Thumbnails.of(fromPic).size(width,height).toFile(toPic);
    }

    /**
     * 修改圖片大小:不遵循原圖高寬比例
     * @throws Exception
     */
    public static void modifyImageSizeKeepAspect(int width,int height) throws Exception{
        File toPic = new File("F:\\20150327232556186_keep_"+ width + "x" +height + ".jpg");
        Thumbnails.of(fromPic).size(width,height).keepAspectRatio(false).toFile(toPic);
    }


    /**
     * 按照指定比例進行縮小和放大
     * @throws Exception
     */
    public static void modifyImageSizeByScale(Double scale) throws Exception{
        File toPic = new File("F:\\20150327232556186_scale"+ scale + ".jpg");
        Thumbnails.of(fromPic).scale(scale).toFile(toPic);
    }

    /**
     * 旋轉圖片
     * @param direction 角度 正數正向轉，負數逆向轉
     * @throws Exception
     */
    public static void modifyImageDirection(int width,int height,double direction) throws Exception{
        File toPic = new File("F:\\20150327232556186_direction"+ direction + ".jpg");
        Thumbnails.of(fromPic).size(width,height).rotate(direction).toFile(toPic);
    }

    /**
     * 圖片加水印
     * @throws Exception
     */
    public static void modifyImageAddSignet(int width,int height) throws Exception{
        File toPic = new File("F:\\20150327232556186_Signet.jpg");
        Thumbnails.of(fromPic)
                .size(width,height)
                .watermark(Positions.TOP_LEFT, ImageIO.read(waterPic),0.5f)
                .outputQuality(1f)
                .toFile(toPic);
    }

    /**
     * 圖片裁剪
     * @throws Exception
     */
    public static void catImage(int width,int height) throws Exception{
        File toPic = new File("F:\\20150327232556186_cat.jpg");
        Thumbnails.of(fromPic)
                .sourceRegion(Positions.CENTER,width,height)
                .size(width,height)
                .outputQuality(1f)
                .toFile(toPic);
        /** 也可以自定義定位0，0表示左上角開始
        Thumbnails.of(fromPic)
                .sourceRegion(0,0,width,height)
                .size(width,height)
                .outputQuality(1f)
                .toFile(toPic);
        */
    }

    /**
     * 轉換圖片格式
     * @throws Exception
     */
    public static void modifyImageFormat() throws Exception{
        File toPic = new File("F:\\20150327232556186_Format.png");
        Thumbnails.of(fromPic)
                .scale(1f)
                .outputFormat("png")
                .outputQuality(1f)
                .toFile(toPic);
    }

    /**
     * 輸出成文件流OutputStream
     * @throws Exception
     */
    public static void modifyImageStream() throws Exception{
        File toPic = new File("F:\\20150327232556186_stream.png");
        OutputStream os=new FileOutputStream(toPic);
        Thumbnails.of(fromPic).scale(1f).toOutputStream(os);
    }


    public static void main(String[] args) throws Exception {
       reduceImage(); //壓縮圖片

        modifyImageSize(200,200); //修改圖片大小:遵循原圖高寬比例

        modifyImageSizeByScale(0.5); //按比例放大縮小
        modifyImageSizeByScale(2.0); //按比例放大縮小

        modifyImageSizeKeepAspect(200,200); //修改圖片大小:不遵循原圖高寬比例

        modifyImageDirection(200,200,90); //旋轉圖片

        modifyImageAddSignet(1024,200); //圖片加水印

        catImage(200,200); //圖片裁剪

        modifyImageFormat(); //轉換圖片格式

        modifyImageStream();
    }
}

效果