如何使 ImageIO 从 InputStream 读取:Java [英] How to make ImageIO read from InputStream :Java

问题描述

我已经创建了可执行的 jar 文件(使用 Eclipse)，有一组图像 (.png) 文件将被包含在 jar 中.所以我在项目的 /images 文件夹中添加了一个包含所有图像的源文件夹.代码必须访问这些文件以使用 ImageIO.read(new File(path);

早些时候，要获取我使用的路径 ClassName.class.getResource(/image/test.png).toURI();

在执行 jar 时，它抛出错误 URI is not hierarchy

所以现在我使用 ClassName.class.getResourceAsStream(/image/test.png);

但是如何让 ImageIO 从 Inputstream 读取?我尝试按如下方式转换

InputStreamReader resourceBuff=ClassName.class.getResourceAsStream(/image/test.png);ImageIO.read((ImageInputStream) new InputStreamReader(resourceBuff));

它抛出错误InputStreamReader cannot be cast to ImageInputStream

解决方案

ImageIO.read() 以 InputStream 作为参数，所以没有强制转换的意义它到 ImageInputStream.

其次，您不能将 InputStreamReader 对象强制转换为 ImageInputStream 因为ImageInputStream和你想到的InputStreamReader没有关系.>

此外getResourceAsStream() 返回 InputStream.所以你可以直接这样做.

InputStream resourceBuff = YourClass.class.getResourceAsStream(filepath);BufferedImage bf = ImageIO.read(resourceBuff);

I have created executable jar file(using Eclipse) , there are a set of image (.png) files that is to be inculded in the jar. So I have added a source folder with all the images inside /images folder in the project . Code has to access these file to create BufferedImage using ImageIO.read(new File(path);

Earlier, To get the path I used ClassName.class.getResource(/image/test.png).toURI();

On executing jar , it throw error URI is not hierarchical

So now I am using ClassName.class.getResourceAsStream(/image/test.png);

But how to make ImageIO read from Inputstream ? I tried cast as follows

InputStreamReader resourceBuff=ClassName.class.getResourceAsStream(/image/test.png);
ImageIO.read((ImageInputStream) new InputStreamReader(resourceBuff));

It throws error InputStreamReader cannot be cast to ImageInputStream

解决方案

ImageIO.read() takes InputStream as a parameter so there is no meaning of casting it to ImageInputStream.

Secondly you can not cast an InputStreamReader object to ImageInputStream because ImageInputStream has nothing to do with InputStreamReader which you thought of.

Moreover getResourceAsStream() returns InputStream. So you can directly do it like this.

InputStream resourceBuff = YourClass.class.getResourceAsStream(filepath);
BufferedImage bf = ImageIO.read(resourceBuff);

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