如何从Java中读取URL中的图像？

Question

我在我的Web应用程序中有servlet提供图像,当我访问那些带有浏览器图像的URL时,服务器是正确的.然后我有另一个调整图像大小的servlet,想法是在resize servlet中通过url访问get图像,然后调整图像大小.但由于某种原因,以下所有方法都返回null,但是当我使用浏览器访问给定的URL时,图像显示正确.

    URL imageURL = new URL(fullUrl);
    // Case 1
    RenderedImage img = ImageIO.read(imageURL);

    // Case 2
    BufferedImage img = JAI.create("url", imageURL).getAsBufferedImage();

    // Case 3
    Image img = java.awt.Toolkit.getDefaultToolkit().getDefaultToolkit().createImage(imageURL);

Answer 1

URL url = new URL("http://www.digitalphotoartistry.com/rose1.jpg");
Image image = ImageIO.read(url);  

要么

URL url = new URL("http://www.digitalphotoartistry.com/rose1.jpg");
java.awt.Image image = java.awt.Toolkit.getDefaultToolkit().createImage(url);   

更新:

此代码适用于我尝试检查您的URL.

public static void main(String[] args) throws Exception {
   URL imageURL = new URL("http://www.digitalphotoartistry.com/rose1.jpg");
    // Case 1
    RenderedImage img = ImageIO.read(imageURL);
    System.out.println(img);
}

输出:

BufferedImage@e80a59: type = 5 ColorModel: #pixelBits = 24 numComponents = 3 col
or space = java.awt.color.ICC_ColorSpace@1ff5ea7 transparency = 1 has alpha = fa
lse isAlphaPre = false ByteInterleavedRaster: width = 553 height = 737 #numDataE
lements 3 dataOff[0] = 2