我怎样才能获得图像的高度和宽度？ [英] How can I get height and width of an image?

问题描述

为什么code以下位返回身高：-1，这意味着高度尚不得而知。如何获取图像的高度？

  {尝试
        //创建图像的位置的URL
        网址URL =新的URL（http://bmw-2006.auto-one.co.uk/wp-content/uploads/bmw-m3-2006-3.jpg）;        //获取图像
        java.awt.Image中的图像= Toolkit.getDefaultToolkit（）的createImage（URL）。        的System.out.println（高度：+ image.getHeight（NULL））;
    }赶上（MalformedURLException的E）{
    }赶上（IOException异常五）{
    }
 

解决方案

使用 ImageIO.read（文件/ URL）来代替。这将阻止同时加载，并返回后，图像的宽度/高度将是已知的。

例如

 进口java.awt.image.BufferedImage中;
进口的javax.swing *。
进口javax.imageio.ImageIO中;
进口的java.net.URL;类SizeOfImage {    公共静态无效的主要（字串[] args）抛出异常{
        网址URL =新的URL（
            http://bmw-2006.auto-one.co.uk/+
            的wp-content /上传/宝马m3-2006-3.jpg）;
        最终的BufferedImage BI = ImageIO.read（URL）;
        最终字符串大小= bi.getWidth（）+X+ bi.getHeight（）;
        SwingUtilities.invokeLater（Runnable的新（）{
            公共无效的run（）{
                JLabel的L =新的JLabel（
                    尺寸，
                    新的ImageIcon（BI），
                    SwingConstants.RIGHT）;
                JOptionPane.showMessageDialog（NULL，L）;
            }
        }）;
    }
}
 

另外，添加一个媒体跟踪​​的图像正在由异步加载工具包和等待，直到它完全加载

Why is the following bit of code returns Height: -1 which means that the height is yet not known. How to get height of the image?

 try {
        // Create a URL for the image's location
        URL url = new URL("http://bmw-2006.auto-one.co.uk/wp-content/uploads/bmw-m3-2006-3.jpg");

        // Get the image
        java.awt.Image image = Toolkit.getDefaultToolkit().createImage(url);

        System.out.println("Height: " + image.getHeight(null));


    } catch (MalformedURLException e) {
    } catch (IOException e) {
    }

解决方案

Use ImageIO.read(File/URL) instead. It will block while loading, and the image width/height will be known after it returns.

E.G.

import java.awt.image.BufferedImage;
import javax.swing.*;
import javax.imageio.ImageIO;
import java.net.URL;

class SizeOfImage {

    public static void main(String[] args) throws Exception {
        URL url = new URL(
            "http://bmw-2006.auto-one.co.uk/" +
            "wp-content/uploads/bmw-m3-2006-3.jpg");
        final BufferedImage bi = ImageIO.read(url);
        final String size = bi.getWidth() + "x" + bi.getHeight();
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JLabel l = new JLabel( 
                    size, 
                    new ImageIcon(bi), 
                    SwingConstants.RIGHT );
                JOptionPane.showMessageDialog(null, l);
            }
        });
    }
}

Alternately, add a MediaTracker to the image being loaded asynchronously by the Toolkit and wait until it is completely loaded.

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