尝试从jar中读取资源文件

Question

I have read every single question and answer regarding this topic and I have tried a multitude of the suggested solutions, none of which are working, currently I am trying to use the URL resource method but url always returns null. Here is my current pseudo setup:

/src/java/pkg/name/is/long/meatpackage/MyClassFile.java

/src/java/pkg/name/is/long/meatpackage/myresources/myresourcefile.txt

@SuppressWarnings("rawtypes")
Class thisClass = Class.forName("pkg.name.is.long.meatpackage.MyClassFile");
ClassLoader cLoader = thisClass.getClassLoader();
//note, I have tried a plethora of variations to the path for the file, this is just one example
URL url = cLoader.getResource("pkg/name/is/long/meatpackage/myresources/myresourcefile.txt");
System.out.println("Found the file!!: " + url);

Seriously, it can't be THIS hard to include a text file in your jar and access it at runtime can it?

When I list the jar it shows that the file is in pkg/name/is/log/meatpackage/myresources/myresourcefile.txt.

Another approach I have tried is:

//along with multiple path combinations for the file the InputStream is always null.    
//multiple paths include but are not limited to:
// "pkg/name/is/long/meatpackage/myresources/myresourcefile.txt"
// "/pkg/name/is/long/meatpackage/myresources/myresourcefile.txt"
// "/myresources/myresourcefile.txt"
// "/myresourcefile.txt"
// "myresourcefile.txt"
InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("myresourcefile.txt"); 
BufferedReader br = new BufferedReader(new InputStreamReader(is)); 

Answer 1

You can simplify this using getClass().getResourceAsStream() or MyClassFile.getResourceAsStream() - you don't need to talk to the classloader directly.

Note that the resource name is slash separated, and if you specify / then it's from the root of the JAR or from the base of the class path, otherwise it's implicitly from the same package directory as the class is.

For example:

package com.example; public class Foo { static { Foo.class.getResourceAsStream("bar.txt"); // looks for /com/example/bar.txt Foo.class.getResourceAsStream("/bar.txt"); // looks for /bar.txt } }

If you're developing inside Eclipse, note that the getResourceAsStream only looks inside the compiled output directory (ie whatever is in bin ). So if you have your resource outside of there, copy it into the src directory (so it gets copied over to the bin directory at build time) and it should find it properly.