java - Java unknown source with ImageIO

Question

My program runs fine in Netbeans, but I get the following error when I run my applet in a browser:

java.lang.IllegalArgumentException: input == null!
    at javax.imageio.ImageIO.read(Unknown Source)

I opened the jar to verify that the png files are correctly placed there. I'm not certain why the following doesn't work (in a try block, of course):

BufferedImage beam = ImageIO.read(this.getClass().getResource("images/beam.png"));

I've tried other things like the following, but suspect the problem might be something else.

URL url = this.getClass().getResource("images/beam.png");
BufferedImage beam = ImageIO.read(url.openStream());

Your advice is appreciated.

score 1 · Accepted Answer

问题出在您的路径字符串中。改用这个：

BufferedImage beam = ImageIO.read(this.getClass().getResource("/images/beam.png"));

（注意/路径前）

score 0 · Accepted Answer

作为记录，如果有人由于某种原因遇到这种类型的错误，eclipse 会自动更改构建路径并阻止图像路径被打包。

要更改此设置，只需right click on the project name-> Properties-> Java Build Path->Source Tab并检查是否不排除包含图像的文件夹，如果它只是删除该规则。

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