java classloader.getSystemResourceAsStream 返回 null
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classloader.getSystemResourceAsStream returns null
提问by Lancelot
I'm trying to load a properties file without using the actual path of the file. I've already done that on some other simple apps using:
我试图在不使用文件的实际路径的情况下加载属性文件。我已经在其他一些简单的应用程序上使用过：
InputStream inputStream = ClassLoader.getSystemResourceAsStream(PROPERTIES_FILE);
props.load(inputStream);
But this time it doesn't work. The inputStream is null for some reason. PROPERTIES_FILE is a constant defined as "app.properties". I tried to remove the .properties extension and got the same results.
但这一次不起作用。由于某种原因， inputStream 为空。PROPERTIES_FILE 是定义为“app.properties”的常量。我试图删除 .properties 扩展名并得到相同的结果。
Any ideas?
有任何想法吗？
Thanks.
谢谢。
回答by jconlin
The PROPERTIES_FILE constant should include the package as well as the properties file (e.g. "com/some/library/file.properties".
PROPERTIES_FILE 常量应该包括包以及属性文件（例如“com/some/library/file.properties”。
final static String PROPS_FILE = "/com/some/library/file.props";
//The preceding "/" is dependendant on wheterh
//you are going to be giving a relative or absolute location
InputStream is = YourCurrentClass.class.getResourceAsStream(PROPS_FILE);
回答by erickson
When getSystemResourceAsStreamreturns null, it means the resource was not found. Make sure the requested resource really is on the classpath at the specified location.
当getSystemResourceAsStream返回时null，表示没有找到资源。确保请求的资源确实位于指定位置的类路径上。
回答by Gogogo
Got the same problem.
遇到了同样的问题。
Reason: I renamed DAOpackage to dao. While exploding the artifact, directory DAOnot get overwritten.
原因：我将DAO包重命名为dao. 爆炸时artifact，目录DAO不会被覆盖。
So I got daoin project internals and DAOin filesystem :facepalm:
所以我进入dao了项目内部和DAO文件系统：facepalm：
