java 判断图片否旋转_java获取图片朝向并旋转

在Java中，可以使用ImageIO类读取图片信息，包括图片的朝向信息。根据朝向信息，可以使用Java Graphics2D类进行旋转操作。

以下是一个示例代码，可以读取图片信息并进行旋转操作：

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;

public class ImageRotationExample {
    public static void main(String[] args) {
        try {
            // 读取图片
            File inputFile = new File("input.jpg");
            BufferedImage inputImage = ImageIO.read(inputFile);

            // 获取朝向信息，如果有朝向信息则旋转图片
            int orientation = getOrientation(inputImage);
            BufferedImage outputImage = inputImage;
            if (orientation != 1) {
                outputImage = rotateImage(inputImage, orientation);
            }

            // 保存旋转后的图片
            File outputFile = new File("output.jpg");
            ImageIO.write(outputImage, "jpg", outputFile);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    // 获取图片朝向信息
    public static int getOrientation(BufferedImage image) {
        int orientation = 1;
        try {
            Object value = image.getProperty("orientation");
            if (value != null) {
                orientation = (Integer) value;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return orientation;
    }

    // 旋转图片
    public static BufferedImage rotateImage(BufferedImage image, int orientation) {
        int width = image.getWidth();
        int height = image.getHeight();
        AffineTransform transform = new AffineTransform();

        switch (orientation) {
            case 2:
                transform = AffineTransform.getScaleInstance(-1, 1);
                transform.translate(-width, 0);
                break;
            case 3:
                transform = AffineTransform.getRotateInstance(Math.PI, width / 2, height / 2);
                break;
            case 4:
                transform = AffineTransform.getScaleInstance(1, -1);
                transform.translate(0, -height);
                break;
            case 5:
                transform = AffineTransform.getScaleInstance(-1, 1);
                transform.translate(-width, 0);
                transform.rotate(Math.toRadians(90), width / 2, height / 2);
                break;
            case 6:
                transform = AffineTransform.getRotateInstance(Math.toRadians(90), width / 2, height / 2);
                break;
            case 7:
                transform = AffineTransform.getScaleInstance(-1, 1);
                transform.translate(-width, 0);
                transform.rotate(Math.toRadians(-90), width / 2, height / 2);
                break;
            case 8:
                transform = AffineTransform.getRotateInstance(Math.toRadians(-90), width / 2, height / 2);
                break;
            default:
                break;
        }

        BufferedImage rotatedImage = new BufferedImage(width, height, image.getType());
        Graphics2D graphics = rotatedImage.createGraphics();
        graphics.drawImage(image, transform, null);
        graphics.dispose();

        return rotatedImage;
    }
}

在该示例代码中，getOrientation()方法用于获取图片的朝向信息，rotateImage()方法用于旋转图片。在rotateImage()方法中，根据不同的朝向信息，使用AffineTransform类进行旋转操作。最后，使用Graphics2D类将旋转后的图片绘制到新的BufferedImage对象中。