如何确定和自动旋转图像？

Roger Rowland提供的元数据提取器指针解决了这个问题。我在这里发布它以备将来参考：

import java.awt.geom.AffineTransform;
import java.awt.image.AffineTransformOp;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;

import com.drew.imaging.ImageMetadataReader;
import com.drew.metadata.Metadata;
import com.drew.metadata.exif.ExifIFD0Directory;
import com.drew.metadata.jpeg.JpegDirectory;

public class Main {

    private static String inFilePath = "C:\\Users\\TapasB\\Desktop\\MHIS031522.jpg";
    private static String outFilePath = "C:\\Users\\TapasB\\Desktop\\MHIS031522-rotated.jpg";

    public static void main(String[] args) throws Exception {
        File imageFile = new File(inFilePath);
        BufferedImage originalImage = ImageIO.read(imageFile);

        Metadata metadata = ImageMetadataReader.readMetadata(imageFile);
        ExifIFD0Directory exifIFD0Directory = metadata.getDirectory(ExifIFD0Directory.class);
        JpegDirectory jpegDirectory = (JpegDirectory) metadata.getDirectory(JpegDirectory.class);

        int orientation = 1;
        try {
            orientation = exifIFD0Directory.getInt(ExifIFD0Directory.TAG_ORIENTATION);
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        int width = jpegDirectory.getImageWidth();
        int height = jpegDirectory.getImageHeight();

        AffineTransform affineTransform = new AffineTransform();

        switch (orientation) {
        case 1:
            break;
        case 2: // Flip X
            affineTransform.scale(-1.0, 1.0);
            affineTransform.translate(-width, 0);
            break;
        case 3: // PI rotation
            affineTransform.translate(width, height);
            affineTransform.rotate(Math.PI);
            break;
        case 4: // Flip Y
            affineTransform.scale(1.0, -1.0);
            affineTransform.translate(0, -height);
            break;
        case 5: // - PI/2 and Flip X
            affineTransform.rotate(-Math.PI / 2);
            affineTransform.scale(-1.0, 1.0);
            break;
        case 6: // -PI/2 and -width
            affineTransform.translate(height, 0);
            affineTransform.rotate(Math.PI / 2);
            break;
        case 7: // PI/2 and Flip
            affineTransform.scale(-1.0, 1.0);
            affineTransform.translate(-height, 0);
            affineTransform.translate(0, width);
            affineTransform.rotate(3 * Math.PI / 2);
            break;
        case 8: // PI / 2
            affineTransform.translate(0, width);
            affineTransform.rotate(3 * Math.PI / 2);
            break;
        default:
            break;
        }       

        AffineTransformOp affineTransformOp = new AffineTransformOp(affineTransform, AffineTransformOp.TYPE_BILINEAR);  
        BufferedImage destinationImage = new BufferedImage(originalImage.getHeight(), originalImage.getWidth(), originalImage.getType());
        destinationImage = affineTransformOp.filter(originalImage, destinationImage);
        ImageIO.write(destinationImage, "jpg", new File(outFilePath));
    }
}

我在使一些开关案例正常工作时遇到了一些问题。即使没有旋转要完成，AffineTransform也会创建一个图像中带有黑色空间的新图像，并会切掉一些尺寸。借用这里接受的答案，我使用元数据提取器类来确定方向应该是什么。然后我使用Imgscalr库进行缩放和旋转。

下面可以看到对我有用的完整解决方案。感谢Tapas Bose的原始解决方案。我希望这对任何人有所帮助！

BufferedImage originalImage = Utils.prepareBufferedImage(fileUpload.getFile_data(), fileUpload.getFile_type());
                    BufferedImage scaledImg = Scalr.resize(originalImage, 200);

                    // ---- Begin orientation handling ----
                    Metadata metadata = ImageMetadataReader.readMetadata(fileUpload.getFile_data());
                    ExifIFD0Directory exifIFD0Directory = metadata.getFirstDirectoryOfType(ExifIFD0Directory.class);

                    int orientation = Integer.parseInt(id);
                    try {
                        orientation = exifIFD0Directory.getInt(ExifIFD0Directory.TAG_ORIENTATION);
                    } catch (Exception ex) {
                        logger.debug("No EXIF information found for image: " + fileUpload.getFile_name());
                    }

                    switch (orientation) {
                    case 1:
                        break;
                    case 2: // Flip X
                        scaledImg = Scalr.rotate(scaledImg, Rotation.FLIP_HORZ);
                        break;
                    case 3: // PI rotation
                        scaledImg = Scalr.rotate(scaledImg, Rotation.CW_180);
                        break;
                    case 4: // Flip Y
                        scaledImg = Scalr.rotate(scaledImg, Rotation.FLIP_VERT);
                        break;
                    case 5: // - PI/2 and Flip X
                        scaledImg = Scalr.rotate(scaledImg, Rotation.CW_90);
                        scaledImg = Scalr.rotate(scaledImg, Rotation.FLIP_HORZ);
                        break;
                    case 6: // -PI/2 and -width
                        scaledImg = Scalr.rotate(scaledImg, Rotation.CW_90);
                        break;
                    case 7: // PI/2 and Flip
                        scaledImg = Scalr.rotate(scaledImg, Rotation.CW_90);
                        scaledImg = Scalr.rotate(scaledImg, Rotation.FLIP_VERT);
                        break;
                    case 8: // PI / 2
                        scaledImg = Scalr.rotate(scaledImg, Rotation.CW_270);
                        break;
                    default:
                        break;
                    }       
                    // ---- End orientation handling ----

                    if(fileUpload.getFile_type().toLowerCase().contains("jpeg")){
                        ImageIO.write(scaledImg, "jpeg", fileUpload.getFile_data());
                        user.setProfile_picture_ext("jpg");
                    }
                    else{
                        Sanselan.writeImage(scaledImg, fileUpload.getFile_data(), ImageFormat.IMAGE_FORMAT_PNG, null);
                        user.setProfile_picture_ext("png");
                    }