通过BufferedImage从文件路径加载图像 [英] Load image from a filepath via BufferedImage

问题描述

我的Java应用程序存在问题，特别是在从计算机中的某个位置加载图像时。
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我使用BufferedImage和InputFileStream在我的计算机中加载图像
首先，我将pic2.jpg图像放入源代码中，没关系。然而，第二，我把这个图像放到另一个地方（在这种情况下是C：\ ImageTest \ pic2.jpg），Java IDE在行显示IllegalArgumentExceptioninput == null

I have a problem with Java application, particular in loading a image from a location in my computer. Follow this post I use BufferedImage and InputFileStream to load a image in my computer First, I put the pic2.jpg image into the source code, it's fine. However, second, i put this image into another place (C:\ImageTest\pic2.jpg in this case), Java IDE show me an IllegalArgumentException "input == null" at line

return ImageIO.read(in);

。我去谷歌搜索确保，我放入代码的链接形式是正确的，所以，我不知道我在哪里做错了....

. I go to google search to make sure that, the form of link that I put into a code is correct, so, i don't know where i did wrong....

这里是代码：

public class MiddlePanel extends JPanel {
private BufferedImage img;

public MiddlePanel(int width){    


    //img = getImage("pic2.jpg");       
    img = getImage("C:\\ImageTest\\pic2.jpg");

    this.setPreferredSize(new Dimension(800,460));

}
public void paintComponent(Graphics g) {
 .....
}
private BufferedImage getImage(String filename) {
// This time, you can use an InputStream to load
try {
        // Grab the InputStream for the image.                    
        InputStream in = getClass().getResourceAsStream(filename);

    // Then read it in.
    return ImageIO.read(in);
} catch (IOException e) {
    System.out.println("The image was not loaded.");
    //System.exit(1);
}
    return null;
}

推荐答案

getResource & getResourceAsStream 不使用文件路径，而是使用相对于代码库的路径。如果代码库是 C：那么找到资源的相对路径是 /ImageTest/pic2.jpg 。

getResource & getResourceAsStream do not work with file paths, but paths relative the code base. If the code base is C: then a relative path that would locate the resource is /ImageTest/pic2.jpg.

..加载文件之间的区别 FileInputStream 和 getResourceAsStream ？

一个主要的区别是 getResource .. 将使用Jar内的资源，该资源不再是文件。因此 FileInputStream 无法用于访问此类资源。

One major difference is that the getResource.. will work with a resource inside a Jar, which is no longer a File. Therefore FileInputStream cannot be used to access such a resource.

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