JSONParser getResourceAsStream

Question

Hi! I am working in a project and I need a resource in it. I am trying to get it using this code:

InputStream is = JSONParser.class.getResourceAsStream("a.json");
String jsonTxt = IOUtils.toString( is );

The file a.json is located in the main file of the project.

The exact problem is:

Exception in thread "main" java.lang.NullPointerException
at java.io.Reader.(Reader.java:61)
at java.io.InputStreamReader.(InputStreamReader.java:55)
at org.apache.commons.io.IOUtils.copy(IOUtils.java:1049)
at org.apache.commons.io.IOUtils.toString(IOUtils.java:359)
at com.playence.parser.JSon.main(JSon.java:28)

Debugging, I saw that variable 'is' is null, and I guess that is why NullPointException, bugt I don't know how to solve it.

Any help?

Thans in advance.

Answer 1

You have the exception because a.json can't be found by your Class.getResourceAsStream() in which case this returns null instead of the stream.

Your a.json file should be in the same package as the JSONParser class the way you have it now. Is that one of your classes or is a utils from an external library?

If it is a library, maybe you can retrieve the stream from a class that is in the same package as a.json and then pass it as parameter:

InputStream is = YourClassBesidesTheFile.class.getResourceAsStream("a.json");
String jsonTxt = IOUtils.toString( is );

or maybe use a full path for the file, something like "/some/package/etc/etc/a.json":

InputStream is = JSONParser.class.getResourceAsStream("/some/package/etc/etc/a.json");
String jsonTxt = IOUtils.toString( is );

To solve the issue, your file must be found by the Class.getResourceAsStream() method although the real issue is in fact retrieving the file content as a stream, no matter how you do that.

Answer 2

Finally I found my problem and I solved it.
It was related with my Eclipse configuration:

Project - propperties - Source

There I had in Myproject/src/main/resources Exclude **.

So the files in that directory wasn't in classes. I solved it just putting Exclude (None).

Now everything is ok. Thank you anyway!