}

输出结果：

[JPEG] - Compression Type = Baseline [JPEG] - Data Precision = 8 bits [JPEG] - Image Height = 1080 pixels [JPEG] - Image Width = 1440 pixels [JPEG] - Number of Components = 3 [JPEG] - Component 1 = Y component: Quantization table 0, Sampling factors 2 horiz/2 vert [JPEG] - Component 2 = Cb component: Quantization table 1, Sampling factors 1 horiz/1 vert [JPEG] - Component 3 = Cr component: Quantization table 1, Sampling factors 1 horiz/1 vert [JFIF] - Version = 1.1 [JFIF] - Resolution Units = none [JFIF] - X Resolution = 72 dots [JFIF] - Y Resolution = 72 dots [JFIF] - Thumbnail Width Pixels = 0 [JFIF] - Thumbnail Height Pixels = 0 [Exif IFD0] - Orientation = Right side, top (Rotate 90 CW) [Exif SubIFD] - Exif Image Width = 1440 pixels [Exif SubIFD] - Exif Image Height = 1080 pixels [ICC Profile] - Profile Size = 548 [ICC Profile] - CMM Type = appl [ICC Profile] - Version = 4.0.0 [ICC Profile] - Class = Display Device [ICC Profile] - Color space = RGB [ICC Profile] - Profile Connection Space = XYZ [ICC Profile] - Profile Date/Time = 2017:07:07 13:22:32 [ICC Profile] - Signature = acsp [ICC Profile] - Primary Platform = Apple Computer, Inc. [ICC Profile] - Device manufacturer = APPL [ICC Profile] - XYZ values = 0.964 1 0.825 [ICC Profile] - Tag Count = 10 [ICC Profile] - Profile Description = Display P3 [ICC Profile] - Profile Copyright = Copyright Apple Inc., 2017 [ICC Profile] - Media White Point = (0.9505, 1, 1.0891) [ICC Profile] - Red Colorant = (0.5151, 0.2412, 65536) [ICC Profile] - Green Colorant = (0.292, 0.6922, 0.0419) [ICC Profile] - Blue Colorant = (0.1571, 0.0666, 0.7841) [ICC Profile] - Red TRC = para (0x70617261): 32 bytes [ICC Profile] - Chromatic Adaptation = sf32 (0x73663332): 44 bytes [ICC Profile] - Blue TRC = para (0x70617261): 32 bytes [ICC Profile] - Green TRC = para (0x70617261): 32 bytes [Photoshop] - Caption Digest = 212 29 140 217 143 0 178 4 233 128 9 152 236 248 66 126 [Huffman] - Number of Tables = 4 Huffman tables [File Type] - Detected File Type Name = JPEG [File Type] - Detected File Type Long Name = Joint Photographic Experts Group [File Type] - Detected MIME Type = image/jpeg [File Type] - Expected File Name Extension = jpg [File] - File Name = 11.jpeg [File] - File Size = 234344 bytes [File] - File Modified Date = 星期日 十一月 07 20:05:52 +08:00 2021

其中`Orientation`标签描述的就是图像旋转的角度。

[Exif IFD0] - Orientation = Right side, top (Rotate 90 CW)

最后，可以通过`Orientation`信息计算出图像对应的旋转角度。
```java
import com.alibaba.fastjson.JSON;
import com.drew.imaging.jpeg.JpegMetadataReader;
import com.drew.metadata.Directory;
import com.drew.metadata.Metadata;
import com.drew.metadata.Tag;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
public class TransferImage {
    public static void main(String[] args) throws IOException {
        String path = "/Users/pzblog/Desktop/11.jpeg";
        int result = getImgRotateAngle(new FileInputStream(path));
        System.out.println(result);
    }
    public static int getImgRotateAngle(InputStream inputStream) {
        int rotateAngle = 0;
        try {
            Metadata metadata = JpegMetadataReader.readMetadata(inputStream);
            Iterable<Directory> directories = metadata.getDirectories();
            for (Directory directory : directories) {
                for (Tag tag : directory.getTags()) {
                    System.out.println(JSON.toJSONString(tag));
                    int tagType = tag.getTagType();
                    //照片拍摄角度信息
                    if (274 == tagType) {
                        String description = tag.getDescription();
                        //Left side, bottom (Rotate 270 CW)
                        switch (description) {
                            //顺时针旋转90度
                            case "Right side, top (Rotate 90 CW)":
                                rotateAngle = 90;
                                break;
                            case "Left side, bottom (Rotate 270 CW)":
                                rotateAngle = 270;
                                break;
                            case "Bottom, right side (Rotate 180)":
                                rotateAngle = 180;
                                break;
                            default:
                                rotateAngle = 0;
                                break;
                        }
                    }
                }
            }
            return rotateAngle;
        } catch (Exception e) {
            return 0;
        }
    }
}

输出的旋转角度结果：

90

• 接着通过旋转角度参数，对图像进行回正 ```java import javax.imageio.ImageIO; import java.awt.*; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException;

public class RotateImage {

public static BufferedImage rotate(Image src, int angel) {
    int src_width = src.getWidth(null);
    int src_height = src.getHeight(null);
    // calculate the new image size
    Rectangle rect_des = calcRotatedSize(new Rectangle(new Dimension(
            src_width, src_height)), angel);
    BufferedImage res = null;
    res = new BufferedImage(rect_des.width, rect_des.height,
            BufferedImage.TYPE_INT_RGB);
    Graphics2D g2 = res.createGraphics();
    // transform
    g2.translate((rect_des.width - src_width) / 2,
            (rect_des.height - src_height) / 2);
    g2.rotate(Math.toRadians(angel), src_width / 2, src_height / 2);
    g2.drawImage(src, null, null);
    return res;
}
public static Rectangle calcRotatedSize(Rectangle src, int angel) {
    // if angel is greater than 90 degree, we need to do some conversion
    if (angel >= 90) {
        if(angel / 90 % 2 == 1){
            int temp = src.height;
            src.height = src.width;
            src.width = temp;
        }
        angel = angel % 90;
    }
    double r = Math.sqrt(src.height * src.height + src.width * src.width) / 2;
    double len = 2 * Math.sin(Math.toRadians(angel) / 2) * r;
    double angel_alpha = (Math.PI - Math.toRadians(angel)) / 2;
    double angel_dalta_width = Math.atan((double) src.height / src.width);
    double angel_dalta_height = Math.atan((double) src.width / src.height);
    int len_dalta_width = (int) (len * Math.cos(Math.PI - angel_alpha
            - angel_dalta_width));
    int len_dalta_height = (int) (len * Math.cos(Math.PI - angel_alpha
            - angel_dalta_height));
    int des_width = src.width + len_dalta_width * 2;
    int des_height = src.height + len_dalta_height * 2;
    return new java.awt.Rectangle(new Dimension(des_width, des_height));
}
public static void main(String[] args) throws IOException {
    BufferedImage src = ImageIO.read(new File("/Users/pzblog/Desktop/11.jpeg"));
    BufferedImage des = RotateImage.rotate(src, 90);
    ImageIO.write(des, "jpg", new File("/Users/pzblog/Desktop/11-rotate.jpeg"));
}

}

- 最后给回正后的图像添加水印
```java
public static void main(String[] args) {
    String srcImgPath = "/Users/pzblog/Desktop/11-rotate.jpeg"; //原始文件地址
    String targetImgPath = "/Users/pzblog/Desktop/1-rotate-copy.jpg"; //目标文件地址
    String text = "复 印 无 效"; //水印文字内容
    Color color = Color.red; //水印文字颜色
    Font font = new Font("宋体", Font.BOLD, 60); //水印文字字体
    float alpha = 0.4f; //水印透明度
    int positionWidth = 320; //水印横向位置坐标
    int positionHeight = 450; //水印纵向位置坐标
    Integer degree = -30; //水印旋转角度
    String location = "center"; //水印的位置
    //给图片添加文字水印
    markImage(srcImgPath, targetImgPath, text, color, font, alpha, positionWidth, positionHeight, degree, location);
}

输入结果：添加水印的结果与预期一致！