Use imgscalr for picture manipulation

  java

maven

        <dependency>
            <groupId>org.imgscalr</groupId>
            <artifactId>imgscalr-lib</artifactId>
            <version>4.2</version>
        </dependency>

resize

##缩放到指定长宽
BufferedImage newImage = Scalr.resize(img,Scalr.Method.SPEED,
targetWidth,targetHeight);
##按比例缩放为长,宽都不超过150的图片
BufferedImage thumbnail = Scalr.resize(image, 150);

rotate

BufferedImage img = ImageIO.read(new File(path));
BufferedImage toImg = Scalr.rotate(img, Scalr.Rotation.CW_90);

crop

BufferedImage img = ImageIO.read(new File(path));
BufferedImage toImg = Scalr.crop(toImg,50,50,400,500);

doc