Java 获取图片的大小、宽、高

参考：https://www.cnblogs.com/hongten/archive/2012/11/26/hongten_java_ImageReader_BufferedImage.html

 import java.awt.image.BufferedImage;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;

 import javax.imageio.ImageIO;

 public class Picture {
     public static void main(String[] args) throws FileNotFoundException, IOException {
         File picture = new File("E:/PrintScreen/StarSky.jpg");
         BufferedImage sourceImg = ImageIO.read(new FileInputStream(picture));

         System.out.println(String.format("Size: %.1f KB", picture.length()/1024.0));
         System.out.println("Width: " + sourceImg.getWidth());
         System.out.println("Height: " + sourceImg.getHeight());
     }
 }

这个没看懂！

 import java.io.File;
 import java.io.IOException;
 import java.util.Iterator;

 import javax.imageio.ImageIO;
 import javax.imageio.ImageReader;
 import javax.imageio.stream.ImageInputStream;

 public class Picture {
     public static void main(String[] args) {
         String srcPath = "E:/PrintScreen/1.jpg";

         File file = new File(srcPath);
         try {
             Iterator<ImageReader> readers = ImageIO.getImageReadersByFormatName("jpg");
             ImageReader reader = (ImageReader) readers.next();
             ImageInputStream iis = ImageIO.createImageInputStream(file);
             reader.setInput(iis, true);
             System.out.println("width: " + reader.getWidth(0));
             System.out.println("height: " + reader.getHeight(0));
         } catch (IOException e) {
             e.printStackTrace();
         }
     }
 }

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注意：图片是预先存放在Java Project下的Package中

 import java.awt.Image;
 import java.awt.image.BufferedImage;
 import java.io.IOException;
 import java.net.URL;

 import javax.imageio.ImageIO;

 public class GetImageSize {
     public static void main(String[] args) throws IOException {
         BufferedImage bi = null;

         try {
             URL u = GetImageSize.class.getClassLoader().getResource("images/background.png");
             bi = ImageIO.read(u);
         } catch (IOException e) {
             e.printStackTrace();
         }
         Image img = bi;

         System.out.println(img.getWidth(null));
         System.out.println(img.getHeight(null));
     }
 }