Java 9.0 | ClassLoader :: getResourceAsStream：NullPointerException [英] Java 9.0 | ClassLoader::getResourceAsStream: NullPointerException

问题描述

下面的这段代码，我从 / resource 文件夹中的文件夹中获取文件，在Java 8中对我来说很好用：

This piece of code down below, where I take my file from folder which is inside the "/resource" folder, works fine for me in Java 8:

//e.g fileName = "folder0/file1.extension2"

ClassLoader classLoader = ResourceLoader.class.getClassLoader();
InputStream in = classLoader.getResourceAsStream(fileName);
Scanner scanner = new Scanner(in, "UTF-8");

在Java 9中没有， classLoader.getResourceAsStream（fileName）返回null：

In Java 9 it does not, classLoader.getResourceAsStream(fileName) returns null:

java.lang.NullPointerException: source

但是，如果我直接使用 / resource 文件夹中的文件，这样可以正常工作：

However, if I use files straight from "/resource" folder, this works fine:

fileName = "file0.extension1"; // It works!

我的问题很明显，说实话，有两个：

My question is quite obvious, to be honest, there are two of them:

1. 发生了什么事？


2. 如何修复？

这是我的项目结构：

*。jar 输出结构：

*.jar:
- javaFolder1
    -javaFolder1.1
        -ResourceLoader.class
        -jclass1.1.2.class
        -jclass1.1.3.class
    -javaFolder1.2
- javaFolder2
    - ..
- ..

- unreachableResourceFolderImTryingToAccess1
    -resource1.1.ext
    -resource1.2.ext
- unreachableResourceFolderImTryingToAccess2
    - ..
- unreachableResourceFolderImTryingToAccess3
    - ..
-resource0.1.ext
-resource0.2.ext
- ..

- somedll1.dll
- somedll2.dll
- ..

推荐答案

e module_info.java文件，你必须打开文件，例如，包名，你在其中的文件是资源，如果那个包在另一个名为resources_module的内部，代码将是：

In the module_info.java file, you have to open the files, for example, the package name, in which you have the files is "resources" and, if that package is inside another called "resources_module" the code will be:

exports resources_module;
opens resources;
opens resources.(the name of another folder inside the package);

现在你可以访问该文件夹了。

And now you can access to that folder.

如何从另一个类访问资源

1. 在resources_module包中创建一个空类



2. 从另一个类（包括其他模块）获取 InputStream ，你必须调用之前创建的类（像这样的空类：

1. Inside the package "resources_module" create a empty class

2. From another class (including other modules), to get an InputStream you have to call the class you created before (the empty class) like this:

（你的空类）.class.getResourceAsStream（path）;

这篇关于Java 9.0 | ClassLoader :: getResourceAsStream：NullPointerException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！