The getResourceAsStream method returns an InputStream for the specified resource or null if it does not find the resource. The getResource method finds a resource with the specified name. It returns a URL to the resource or null if it does not find the resource. Calling java.
You should always close streams (and any other Closeable, actually), no matter how they were given to you.
The java. lang. Class. getResourceAsStream() finds a resource with a given name.It returns a InputStream object or null if no resource with this name is found.
Lifepaths.class.getClass().getResourceAsStream(...)
loads resources using system class loader, it obviously fails because it does not see your JARs
Lifepaths.class.getResourceAsStream(...)
loads resources using the same class loader that loaded Lifepaths class and it should have access to resources in your JARs
The rules are as follows:
And try:
Lifepaths.class.getResourceAsStream("/initialization/Lifepaths.txt")
instead of
Lifepaths.class.getClass().getResourceAsStream("/initialization/Lifepaths.txt")
(not sure if it makes a difference, but the former will use the correct ClassLoader/ JAR, while I'm not sure with the latter)
So there are several ways to get a resource from a jar and each has slightly different syntax where the path needs to be specified differently.
The best explanation I have seen is this article from InfoWorld. I'll summarize here, but if you want to know more you should check out the article.
Methods
ClassLoader.getResourceAsStream()
.Format: "/"-separated names; no leading "/" (all names are absolute).
Example: this.getClass().getClassLoader().getResourceAsStream("some/pkg/resource.properties");
Class.getResourceAsStream()
Format: "/"-separated names; leading "/" indicates absolute names; all other names are relative to the class's package
Example: this.getClass().getResourceAsStream("/some/pkg/resource.properties");
Updated Sep 2020: Changed article link. Original article was from Javaworld, it is now hosted on InfoWorld (and has many more ads)
Don't use absolute paths, make them relative to the 'resources' directory in your project. Quick and dirty code that displays the contents of MyTest.txt from the directory 'resources'.
@Test
public void testDefaultResource() {
// can we see default resources
BufferedInputStream result = (BufferedInputStream)
Config.class.getClassLoader().getResourceAsStream("MyTest.txt");
byte [] b = new byte[256];
int val = 0;
String txt = null;
do {
try {
val = result.read(b);
if (val > 0) {
txt += new String(b, 0, val);
}
} catch (IOException e) {
e.printStackTrace();
}
} while (val > -1);
System.out.println(txt);
}
You might want to try this to get the stream i.e first get the url and then open it as stream.
URL url = getClass().getResource("/initialization/Lifepaths.txt");
InputStream strm = url.openStream();
I once had a similar question: Reading txt file from jar fails but reading image works
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