如何使用Java 9中的类加载器访问资源 [英] How to access resource using class loader in Java 9

问题描述

我在eclipse中有一个gradle项目。这是我项目的结构

I have a gradle project in eclipse. Here is the structure of my project

我有css资源 styleclass.css 在 scr / main / resources / css 中。首先我尝试使用

I have css resource styleclass.css in scr/main/resources/css. First I tried to access it using

scene.getStylesheets().add("css/styleclass.css"); 

但我收到警告资源未找到。我还尝试删除 module-info.java 文件。但结果是一样的。

But I was getting warning resource not found. I also tried it by removing module-info.java file. But result is same.

然后我尝试使用

String urlString = ComboBoxStyling.class.getClassLoader().getResource("css/styleclass.css").toExternalForm();

问题是，如果我删除 moduele-info.java 并应用了样式表。但是使用 module-info.java 我得到空指针异常。

Problem is, this line works if I remove moduele-info.java and style sheet applied. But with module-info.java I am getting null pointer exception.

我不太了解，但至少我知道类加载器在Java 9中有变化。那么我怎么能在Java 9中做同样的事情。我的 module-info.java 文件包含以下内容

I don't know much but atleast I know that class loader have changes in Java 9. So how can I do the same in Java 9. My module-info.java file contains the following

module pk.training.basit {
    exports pk.training.basit;
    requires transitive javafx.controls;
}

谢谢&问候

Basit Mahmood Ahmed

Basit Mahmood Ahmed

推荐答案

你应该把你的css放入与使用它的类相同的包，然后使用Class.getResource来访问它，使用相对的Path。

You should put your css in the same package as the class which uses it, then use Class.getResource to access it, with the relative Path.

src/main/java:
  pk.training.basit
    ComboBoxStyling.java

src/main/resources:
  pk.training.basit
    ComboBoxStyling.css

然后在源代码中：

scene.getStylesheets().add(
  ComboBoxStyling.class.getResource("ComboBoxStyling.css").toExternalForm());

我个人认为将css和类放在同一目录中更好的做法，然后configure gradle so它可以获取src / main目录中的资源。它允许具有类似于其他GUI产品（Angular）的体系结构，其将包括源的屏幕的所有资源放置在同一目录中，例如FXML文件（例如，如果有的话）。

Personnally I think it's even a better practice to put the css and the class in the same directory, then configure gradle so It can take the resources in the src/main directory. It permits to have an architecture analog to other GUI products (Angular) which places all the resources of a screen including the source in the same directory, the FXML file for example if you had one.

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