JAVA高级面试进阶训练营视频教程

admin

 

 

<dependency>
<groupId>com.drewnoakes</groupId>
<artifactId>metadata-extractor</artifactId>
<version>2.11.0</version>
</dependency>

 

 

import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;

import com.drew.imaging.jpeg.JpegMetadataReader;
import com.drew.imaging.jpeg.JpegProcessingException;
import com.drew.metadata.Directory;
import com.drew.metadata.Metadata;
import com.drew.metadata.MetadataException;
import com.drew.metadata.exif.ExifDirectoryBase;

public class Demo {
    

    // 处理ios图片旋转的问题
    public static void getPictureByName(String filePath,String name){

        try {
            //name为前端请求图片名，如 a.jpg
            BufferedImage src = getPicture(filePath+name);
            BufferedImage bi = null;

            //图片存在
            if(src != null){
                //获取图片旋转角度
                int angel = getRotateAngleForPhoto(filePath+name);
                //图片被翻转，调整图片
                if(angel != 0){
                    int src_width = src.getWidth(null);
                    int src_height = src.getHeight(null);
                    Rectangle rect_des = CalcRotatedSize(new Rectangle(new Dimension(src_width, src_height)), angel);

                    bi = new BufferedImage(rect_des.width, rect_des.height,BufferedImage.TYPE_INT_RGB);
                    Graphics2D g2 = bi.createGraphics();

                    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);
                    
                    int index = name.lastIndexOf(".");
                    String formate = name.substring(index+1);
                    ImageIO.write(bi, formate, new File(filePath+name));
                }
            }else{
                //图片不存在
                System.out.println("图片不存在");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    /**
     * 读取指定图片
     */
    public static BufferedImage getPicture(String path) {
        BufferedImage bi = null;
        try{
            File file = new File(path);
            if(!file.exists()){
                return null;
            }
            bi = ImageIO.read(file);
        } catch (Exception e){
            e.printStackTrace();
        }
        return bi;
    }


    /**
     * 图片翻转时，计算图片翻转到正常显示需旋转角度
     */
    public static int getRotateAngleForPhoto(String fileName){

        File file = new File(fileName);

        int angel = 0;
        Metadata metadata;

        try{
            metadata = JpegMetadataReader.readMetadata(file);
            Directory directory = metadata.getFirstDirectoryOfType(ExifDirectoryBase.class);
            if(directory != null && directory.containsTag(ExifDirectoryBase.TAG_ORIENTATION)){
                // Exif信息中方向　　
                int orientation = directory.getInt(ExifDirectoryBase.TAG_ORIENTATION);
                // 原图片的方向信息
                if(6 == orientation ){
                    //6旋转90
                    angel = 90;
                }else if( 3 == orientation){
                    //3旋转180
                    angel = 180;
                }else if( 8 == orientation){
                    //8旋转90
                    angel = 270;
                }
            }
        } catch(JpegProcessingException e){
            e.printStackTrace();
        } catch(MetadataException e){
            e.printStackTrace();
        } catch(Exception e){
            e.printStackTrace();
        }
        System.out.println("图片旋转角度：" + angel);
        return angel;
    }


    /**
     * 计算旋转参数
     */
    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 / 9%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 Exception {
         String filePath ="d:/" ;
         String filename = "333.jpg";
         //处理ios图片旋转的问题
         getPictureByName(filePath,filename);
    }
}